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1 /*
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2 * $Header: /cvshome/build/org.osgi.framework/src/org/osgi/framework/BundleContext.java,v 1.22 2007/02/21 16:49:05 hargrave Exp $
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3 *
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4 * Copyright (c) OSGi Alliance (2000, 2007). All Rights Reserved.
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5 *
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6 * Licensed under the Apache License, Version 2.0 (the "License");
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7 * you may not use this file except in compliance with the License.
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8 * You may obtain a copy of the License at
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9 *
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10 * http://www.apache.org/licenses/LICENSE-2.0
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11 *
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12 * Unless required by applicable law or agreed to in writing, software
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13 * distributed under the License is distributed on an "AS IS" BASIS,
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14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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15 * See the License for the specific language governing permissions and
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16 * limitations under the License.
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17 */
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18
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19 module org.osgi.framework.BundleContext;
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20 import org.osgi.framework.Bundle;
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21 import org.osgi.framework.BundleListener;
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22 import org.osgi.framework.ServiceListener;
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23 import org.osgi.framework.FrameworkListener;
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24 import org.osgi.framework.ServiceReference;
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25 import org.osgi.framework.ServiceRegistration;
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26 import org.osgi.framework.Filter;
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27
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28 import java.lang.all;
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29 import java.io.File;
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30 import java.io.InputStream;
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31 import java.util.Dictionary;
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32
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33 /**
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34 * A bundle's execution context within the Framework. The context is used to
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35 * grant access to other methods so that this bundle can interact with the
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36 * Framework.
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37 *
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38 * <p>
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39 * <code>BundleContext</code> methods allow a bundle to:
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40 * <ul>
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41 * <li>Subscribe to events published by the Framework.
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42 * <li>Register service objects with the Framework service registry.
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43 * <li>Retrieve <code>ServiceReferences</code> from the Framework service
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44 * registry.
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45 * <li>Get and release service objects for a referenced service.
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46 * <li>Install new bundles in the Framework.
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47 * <li>Get the list of bundles installed in the Framework.
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48 * <li>Get the {@link Bundle} object for a bundle.
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49 * <li>Create <code>File</code> objects for files in a persistent storage
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50 * area provided for the bundle by the Framework.
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51 * </ul>
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52 *
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53 * <p>
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54 * A <code>BundleContext</code> object will be created and provided to the
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55 * bundle associated with this context when it is started using the
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56 * {@link BundleActivator#start} method. The same <code>BundleContext</code>
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57 * object will be passed to the bundle associated with this context when it is
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58 * stopped using the {@link BundleActivator#stop} method. A
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59 * <code>BundleContext</code> object is generally for the private use of its
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60 * associated bundle and is not meant to be shared with other bundles in the
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61 * OSGi environment.
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62 *
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63 * <p>
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64 * The <code>Bundle</code> object associated with a <code>BundleContext</code>
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65 * object is called the <em>context bundle</em>.
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66 *
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67 * <p>
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68 * The <code>BundleContext</code> object is only valid during the execution of
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69 * its context bundle; that is, during the period from when the context bundle
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70 * is in the <code>STARTING</code>, <code>STOPPING</code>, and
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71 * <code>ACTIVE</code> bundle states. If the <code>BundleContext</code>
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72 * object is used subsequently, an <code>IllegalStateException</code> must be
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73 * thrown. The <code>BundleContext</code> object must never be reused after
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74 * its context bundle is stopped.
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75 *
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76 * <p>
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77 * The Framework is the only entity that can create <code>BundleContext</code>
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78 * objects and they are only valid within the Framework that created them.
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79 *
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80 * @ThreadSafe
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81 * @version $Revision: 1.22 $
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82 */
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83
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84 public interface BundleContext {
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85 /**
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86 * Returns the value of the specified property. If the key is not found in
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87 * the Framework properties, the system properties are then searched. The
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88 * method returns <code>null</code> if the property is not found.
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89 *
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90 * <p>
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91 * The Framework defines the following standard property keys:
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92 * </p>
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93 * <ul>
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94 * <li>{@link Constants#FRAMEWORK_VERSION} - The OSGi Framework version.
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95 * </li>
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96 * <li>{@link Constants#FRAMEWORK_VENDOR} - The Framework implementation
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97 * vendor.</li>
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98 * <li>{@link Constants#FRAMEWORK_LANGUAGE} - The language being used. See
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99 * ISO 639 for possible values.</li>
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100 * <li>{@link Constants#FRAMEWORK_OS_NAME} - The host computer operating
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101 * system.</li>
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102 * <li>{@link Constants#FRAMEWORK_OS_VERSION} - The host computer
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103 * operating system version number.</li>
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104 * <li>{@link Constants#FRAMEWORK_PROCESSOR} - The host computer processor
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105 * name.</li>
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106 * </ul>
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107 * <p>
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108 * All bundles must have permission to read these properties.
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109 *
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110 * <p>
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111 * Note: The last four standard properties are used by the
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112 * {@link Constants#BUNDLE_NATIVECODE} <code>Manifest</code> header's
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113 * matching algorithm for selecting native language code.
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114 *
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115 * @param key The name of the requested property.
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116 * @return The value of the requested property, or <code>null</code> if
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117 * the property is undefined.
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118 * @throws java.lang.SecurityException If the caller does not have the
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119 * appropriate <code>PropertyPermission</code> to read the
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120 * property, and the Java Runtime Environment supports permissions.
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121 */
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122 public String getProperty(String key);
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123
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124 /**
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125 * Returns the <code>Bundle</code> object associated with this
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126 * <code>BundleContext</code>. This bundle is called the context bundle.
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127 *
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128 * @return The <code>Bundle</code> object associated with this
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129 * <code>BundleContext</code>.
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130 * @throws java.lang.IllegalStateException If this BundleContext is no
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131 * longer valid.
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132 */
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133 public Bundle getBundle();
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134
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135 /**
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136 * Installs a bundle from the specified location string. A bundle is
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137 * obtained from <code>location</code> as interpreted by the Framework in
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138 * an implementation dependent manner.
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139 * <p>
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140 * Every installed bundle is uniquely identified by its location string,
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141 * typically in the form of a URL.
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142 *
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143 * <p>
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144 * The following steps are required to install a bundle:
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145 * <ol>
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146 * <li>If a bundle containing the same location string is already
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147 * installed, the <code>Bundle</code> object for that bundle is returned.
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148 *
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149 * <li>The bundle's content is read from the location string. If this
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150 * fails, a {@link BundleException} is thrown.
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151 *
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152 * <li>The bundle's <code>Bundle-NativeCode</code> dependencies are
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153 * resolved. If this fails, a <code>BundleException</code> is thrown.
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154 *
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155 * <li>The bundle's associated resources are allocated. The associated
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156 * resources minimally consist of a unique identifier and a persistent
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157 * storage area if the platform has file system support. If this step fails,
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158 * a <code>BundleException</code> is thrown.
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159 *
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160 * <li>If the bundle has declared an Bundle-RequiredExecutionEnvironment
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161 * header, then the listed execution environments must be verified against
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162 * the installed execution environments. If none of the listed execution
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163 * environments match an installed execution environment, a
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164 * <code>BundleException</code> must be thrown.
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165 *
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166 * <li>The bundle's state is set to <code>INSTALLED</code>.
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167 *
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168 * <li>A bundle event of type {@link BundleEvent#INSTALLED} is fired.
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169 *
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170 * <li>The <code>Bundle</code> object for the newly or previously
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171 * installed bundle is returned.
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172 * </ol>
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173 *
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174 * <b>Postconditions, no exceptions thrown </b>
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175 * <ul>
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176 * <li><code>getState()</code> in {<code>INSTALLED</code>,<code>RESOLVED</code>}.
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177 * <li>Bundle has a unique ID.
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178 * </ul>
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179 * <b>Postconditions, when an exception is thrown </b>
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180 * <ul>
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181 * <li>Bundle is not installed and no trace of the bundle exists.
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182 * </ul>
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183 *
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184 * @param location The location identifier of the bundle to install.
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185 * @return The <code>Bundle</code> object of the installed bundle.
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186 * @throws BundleException If the installation failed.
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187 * @throws java.lang.SecurityException If the caller does not have the
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188 * appropriate <code>AdminPermission[installed bundle,LIFECYCLE]</code>, and the
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189 * Java Runtime Environment supports permissions.
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190 * @throws java.lang.IllegalStateException If this BundleContext is no
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191 * longer valid.
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192 */
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193 public Bundle installBundle(String location);
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194
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195 /**
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196 * Installs a bundle from the specified <code>InputStream</code> object.
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197 *
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198 * <p>
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199 * This method performs all of the steps listed in
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200 * <code>BundleContext.installBundle(String location)</code>, except that
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201 * the bundle's content will be read from the <code>InputStream</code>
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202 * object. The location identifier string specified will be used as the
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203 * identity of the bundle.
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204 *
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205 * <p>
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206 * This method must always close the <code>InputStream</code> object, even
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207 * if an exception is thrown.
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208 *
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209 * @param location The location identifier of the bundle to install.
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210 * @param input The <code>InputStream</code> object from which this bundle
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211 * will be read.
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212 * @return The <code>Bundle</code> object of the installed bundle.
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213 * @throws BundleException If the provided stream cannot be read or the
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214 * installation failed.
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215 * @throws java.lang.SecurityException If the caller does not have the
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216 * appropriate <code>AdminPermission[installed bundle,LIFECYCLE]</code>, and the
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217 * Java Runtime Environment supports permissions.
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218 * @throws java.lang.IllegalStateException If this BundleContext is no
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219 * longer valid.
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220 * @see #installBundle(java.lang.String)
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221 */
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222 public Bundle installBundle(String location, InputStream input);
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223
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224 /**
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225 * Returns the bundle with the specified identifier.
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226 *
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227 * @param id The identifier of the bundle to retrieve.
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228 * @return A <code>Bundle</code> object or <code>null</code> if the
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229 * identifier does not match any installed bundle.
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230 */
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231 public Bundle getBundle(long id);
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232
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233 /**
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234 * Returns a list of all installed bundles.
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235 * <p>
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236 * This method returns a list of all bundles installed in the OSGi
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237 * environment at the time of the call to this method. However, since the
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238 * Framework is a very dynamic environment, bundles can be installed or
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239 * uninstalled at anytime.
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240 *
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241 * @return An array of <code>Bundle</code> objects, one object per
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242 * installed bundle.
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243 */
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244 public Bundle[] getBundles();
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245
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246 /**
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247 * Adds the specified <code>ServiceListener</code> object with the
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248 * specified <code>filter</code> to the context bundle's list of
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249 * listeners. See {@link Filter} for a description of the filter syntax.
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250 * <code>ServiceListener</code> objects are notified when a service has a
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251 * lifecycle state change.
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252 *
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253 * <p>
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254 * If the context bundle's list of listeners already contains a listener
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255 * <code>l</code> such that <code>(l==listener)</code>, then this
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256 * method replaces that listener's filter (which may be <code>null</code>)
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257 * with the specified one (which may be <code>null</code>).
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258 *
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259 * <p>
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260 * The listener is called if the filter criteria is met. To filter based
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261 * upon the class of the service, the filter should reference the
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262 * {@link Constants#OBJECTCLASS} property. If <code>filter</code> is
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263 * <code>null</code>, all services are considered to match the filter.
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264 *
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265 * <p>
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266 * When using a <code>filter</code>, it is possible that the
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267 * <code>ServiceEvent</code>s for the complete lifecycle of a service
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268 * will not be delivered to the listener. For example, if the
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269 * <code>filter</code> only matches when the property <code>x</code> has
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270 * the value <code>1</code>, the listener will not be called if the
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271 * service is registered with the property <code>x</code> not set to the
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272 * value <code>1</code>. Subsequently, when the service is modified
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273 * setting property <code>x</code> to the value <code>1</code>, the
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274 * filter will match and the listener will be called with a
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275 * <code>ServiceEvent</code> of type <code>MODIFIED</code>. Thus, the
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276 * listener will not be called with a <code>ServiceEvent</code> of type
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277 * <code>REGISTERED</code>.
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278 *
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279 * <p>
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280 * If the Java Runtime Environment supports permissions, the
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281 * <code>ServiceListener</code> object will be notified of a service event
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282 * only if the bundle that is registering it has the
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283 * <code>ServicePermission</code> to get the service using at least one of
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284 * the named classes the service was registered under.
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285 *
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286 * @param listener The <code>ServiceListener</code> object to be added.
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287 * @param filter The filter criteria.
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288 *
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289 * @throws InvalidSyntaxException If <code>filter</code> contains an
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290 * invalid filter string that cannot be parsed.
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291 * @throws java.lang.IllegalStateException If this BundleContext is no
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292 * longer valid.
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293 *
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294 * @see ServiceEvent
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295 * @see ServiceListener
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296 * @see ServicePermission
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297 */
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298 public void addServiceListener(ServiceListener listener,
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299 String filter);
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300
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301 /**
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302 * Adds the specified <code>ServiceListener</code> object to the context
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303 * bundle's list of listeners.
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304 *
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305 * <p>
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306 * This method is the same as calling
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307 * <code>BundleContext.addServiceListener(ServiceListener listener,
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308 * String filter)</code>
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309 * with <code>filter</code> set to <code>null</code>.
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310 *
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311 * @param listener The <code>ServiceListener</code> object to be added.
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312 * @throws java.lang.IllegalStateException If this BundleContext is no
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313 * longer valid.
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314 *
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315 * @see #addServiceListener(ServiceListener, String)
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316 */
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317 public void addServiceListener(ServiceListener listener);
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318
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319 /**
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320 * Removes the specified <code>ServiceListener</code> object from the
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321 * context bundle's list of listeners.
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322 *
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323 * <p>
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324 * If <code>listener</code> is not contained in this context bundle's list
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325 * of listeners, this method does nothing.
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326 *
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327 * @param listener The <code>ServiceListener</code> to be removed.
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328 * @throws java.lang.IllegalStateException If this BundleContext is no
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329 * longer valid.
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330 */
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331 public void removeServiceListener(ServiceListener listener);
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332
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333 /**
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334 * Adds the specified <code>BundleListener</code> object to the context
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335 * bundle's list of listeners if not already present. BundleListener objects
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336 * are notified when a bundle has a lifecycle state change.
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337 *
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338 * <p>
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339 * If the context bundle's list of listeners already contains a listener
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340 * <code>l</code> such that <code>(l==listener)</code>, this method
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341 * does nothing.
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342 *
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343 * @param listener The <code>BundleListener</code> to be added.
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344 * @throws java.lang.IllegalStateException If this BundleContext is no
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345 * longer valid.
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346 * @throws java.lang.SecurityException If listener is a
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347 * <code>SynchronousBundleListener</code> and the caller does not
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348 * have the appropriate <code>AdminPermission[context bundle,LISTENER]</code>,
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349 * and the Java Runtime Environment supports permissions.
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350 *
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351 * @see BundleEvent
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352 * @see BundleListener
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353 */
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354 public void addBundleListener(BundleListener listener);
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355
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356 /**
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357 * Removes the specified <code>BundleListener</code> object from the
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358 * context bundle's list of listeners.
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359 *
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360 * <p>
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361 * If <code>listener</code> is not contained in the context bundle's list
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362 * of listeners, this method does nothing.
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363 *
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364 * @param listener The <code>BundleListener</code> object to be removed.
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365 * @throws java.lang.IllegalStateException If this BundleContext is no
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366 * longer valid.
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367 * @throws java.lang.SecurityException If listener is a
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368 * <code>SynchronousBundleListener</code> and the caller does not
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369 * have the appropriate <code>AdminPermission[context bundle,LISTENER]</code>,
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370 * and the Java Runtime Environment supports permissions.
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371 */
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372 public void removeBundleListener(BundleListener listener);
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373
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374 /**
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375 * Adds the specified <code>FrameworkListener</code> object to the context
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376 * bundle's list of listeners if not already present. FrameworkListeners are
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377 * notified of general Framework events.
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378 *
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379 * <p>
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380 * If the context bundle's list of listeners already contains a listener
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381 * <code>l</code> such that <code>(l==listener)</code>, this method
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382 * does nothing.
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383 *
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384 * @param listener The <code>FrameworkListener</code> object to be added.
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385 * @throws java.lang.IllegalStateException If this BundleContext is no
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386 * longer valid.
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387 *
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388 * @see FrameworkEvent
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389 * @see FrameworkListener
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390 */
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391 public void addFrameworkListener(FrameworkListener listener);
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392
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393 /**
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394 * Removes the specified <code>FrameworkListener</code> object from the
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395 * context bundle's list of listeners.
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396 *
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397 * <p>
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398 * If <code>listener</code> is not contained in the context bundle's list
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399 * of listeners, this method does nothing.
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400 *
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401 * @param listener The <code>FrameworkListener</code> object to be
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402 * removed.
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403 * @throws java.lang.IllegalStateException If this BundleContext is no
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404 * longer valid.
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405 */
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406 public void removeFrameworkListener(FrameworkListener listener);
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407
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408 /**
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409 * Registers the specified service object with the specified properties
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410 * under the specified class names into the Framework. A
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411 * <code>ServiceRegistration</code> object is returned. The
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412 * <code>ServiceRegistration</code> object is for the private use of the
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413 * bundle registering the service and should not be shared with other
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414 * bundles. The registering bundle is defined to be the context bundle.
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415 * Other bundles can locate the service by using either the
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416 * {@link #getServiceReferences} or {@link #getServiceReference} method.
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417 *
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418 * <p>
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419 * A bundle can register a service object that implements the
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420 * {@link ServiceFactory} interface to have more flexibility in providing
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421 * service objects to other bundles.
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422 *
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423 * <p>
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424 * The following steps are required to register a service:
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425 * <ol>
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426 * <li>If <code>service</code> is not a <code>ServiceFactory</code>,
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427 * an <code>IllegalArgumentException</code> is thrown if
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428 * <code>service</code> is not an <code>instanceof</code> all the
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429 * classes named.
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430 * <li>The Framework adds these service properties to the specified
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431 * <code>Dictionary</code> (which may be <code>null</code>): a property
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432 * named {@link Constants#SERVICE_ID} identifying the registration number of
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433 * the service and a property named {@link Constants#OBJECTCLASS} containing
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434 * all the specified classes. If any of these properties have already been
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435 * specified by the registering bundle, their values will be overwritten by
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436 * the Framework.
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437 * <li>The service is added to the Framework service registry and may now
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438 * be used by other bundles.
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439 * <li>A service event of type {@link ServiceEvent#REGISTERED} is
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440 * fired.
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441 * <li>A <code>ServiceRegistration</code> object for this registration is
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442 * returned.
|
|
443 * </ol>
|
|
444 *
|
|
445 * @param clazzes The class names under which the service can be located.
|
|
446 * The class names in this array will be stored in the service's
|
|
447 * properties under the key {@link Constants#OBJECTCLASS}.
|
|
448 * @param service The service object or a <code>ServiceFactory</code>
|
|
449 * object.
|
|
450 * @param properties The properties for this service. The keys in the
|
|
451 * properties object must all be <code>String</code> objects. See
|
|
452 * {@link Constants} for a list of standard service property keys.
|
|
453 * Changes should not be made to this object after calling this
|
|
454 * method. To update the service's properties the
|
|
455 * {@link ServiceRegistration#setProperties} method must be called.
|
|
456 * The set of properties may be <code>null</code> if the service
|
|
457 * has no properties.
|
|
458 *
|
|
459 * @return A <code>ServiceRegistration</code> object for use by the bundle
|
|
460 * registering the service to update the service's properties or to
|
|
461 * unregister the service.
|
|
462 *
|
|
463 * @throws java.lang.IllegalArgumentException If one of the following is
|
|
464 * true:
|
|
465 * <ul>
|
|
466 * <li><code>service</code> is <code>null</code>.
|
|
467 * <li><code>service</code> is not a <code>ServiceFactory</code>
|
|
468 * object and is not an instance of all the named classes in
|
|
469 * <code>clazzes</code>.
|
|
470 * <li><code>properties</code> contains case variants of the same
|
|
471 * key name.
|
|
472 * </ul>
|
|
473 *
|
|
474 * @throws java.lang.SecurityException If the caller does not have the
|
|
475 * <code>ServicePermission</code> to register the service for all
|
|
476 * the named classes and the Java Runtime Environment supports
|
|
477 * permissions.
|
|
478 *
|
|
479 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
480 * longer valid.
|
|
481 *
|
|
482 * @see ServiceRegistration
|
|
483 * @see ServiceFactory
|
|
484 */
|
|
485 public ServiceRegistration registerService(String[] clazzes,
|
|
486 Object service, Dictionary properties);
|
|
487
|
|
488 /**
|
|
489 * Registers the specified service object with the specified properties
|
|
490 * under the specified class name with the Framework.
|
|
491 *
|
|
492 * <p>
|
|
493 * This method is otherwise identical to
|
|
494 * {@link #registerService(java.lang.String[], java.lang.Object,
|
|
495 * java.util.Dictionary)} and is provided as a convenience when
|
|
496 * <code>service</code> will only be registered under a single class name.
|
|
497 * Note that even in this case the value of the service's
|
|
498 * {@link Constants#OBJECTCLASS} property will be an array of strings,
|
|
499 * rather than just a single string.
|
|
500 *
|
|
501 * @param clazz The class name under which the service can be located.
|
|
502 * @param service The service object or a <code>ServiceFactory</code>
|
|
503 * object.
|
|
504 * @param properties The properties for this service.
|
|
505 *
|
|
506 * @return A <code>ServiceRegistration</code> object for use by the bundle
|
|
507 * registering the service to update the service's properties or to
|
|
508 * unregister the service.
|
|
509 *
|
|
510 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
511 * longer valid.
|
|
512 * @see #registerService(java.lang.String[], java.lang.Object,
|
|
513 * java.util.Dictionary)
|
|
514 */
|
|
515 public ServiceRegistration registerService(String clazz,
|
|
516 Object service, Dictionary properties);
|
|
517
|
|
518 /**
|
|
519 * Returns an array of <code>ServiceReference</code> objects. The returned
|
|
520 * array of <code>ServiceReference</code> objects contains services that
|
|
521 * were registered under the specified class, match the specified filter
|
|
522 * criteria, and the packages for the class names under which the services
|
|
523 * were registered match the context bundle's packages as defined in
|
|
524 * {@link ServiceReference#isAssignableTo(Bundle, String)}.
|
|
525 *
|
|
526 * <p>
|
|
527 * The list is valid at the time of the call to this method, however since
|
|
528 * the Framework is a very dynamic environment, services can be modified or
|
|
529 * unregistered at anytime.
|
|
530 *
|
|
531 * <p>
|
|
532 * <code>filter</code> is used to select the registered service whose
|
|
533 * properties objects contain keys and values which satisfy the filter. See
|
|
534 * {@link Filter} for a description of the filter string syntax.
|
|
535 *
|
|
536 * <p>
|
|
537 * If <code>filter</code> is <code>null</code>, all registered services
|
|
538 * are considered to match the filter. If <code>filter</code> cannot be
|
|
539 * parsed, an {@link InvalidSyntaxException} will be thrown with a human
|
|
540 * readable message where the filter became unparsable.
|
|
541 *
|
|
542 * <p>
|
|
543 * The following steps are required to select a set of
|
|
544 * <code>ServiceReference</code> objects:
|
|
545 * <ol>
|
|
546 * <li>If the filter string is not <code>null</code>, the filter string
|
|
547 * is parsed and the set <code>ServiceReference</code> objects of
|
|
548 * registered services that satisfy the filter is produced. If the filter
|
|
549 * string is <code>null</code>, then all registered services are
|
|
550 * considered to satisfy the filter.
|
|
551 * <li>If the Java Runtime Environment supports permissions, the set of
|
|
552 * <code>ServiceReference</code> objects produced by the previous step is
|
|
553 * reduced by checking that the caller has the
|
|
554 * <code>ServicePermission</code> to get at least one of the class names
|
|
555 * under which the service was registered. If the caller does not have the
|
|
556 * correct permission for a particular <code>ServiceReference</code>
|
|
557 * object, then it is removed from the set.
|
|
558 * <li>If <code>clazz</code> is not <code>null</code>, the set is
|
|
559 * further reduced to those services that are an <code>instanceof</code>
|
|
560 * and were registered under the specified class. The complete list of
|
|
561 * classes of which a service is an instance and which were specified when
|
|
562 * the service was registered is available from the service's
|
|
563 * {@link Constants#OBJECTCLASS} property.
|
|
564 * <li>The set is reduced one final time by cycling through each
|
|
565 * <code>ServiceReference</code> object and calling
|
|
566 * {@link ServiceReference#isAssignableTo(Bundle, String)} with the context
|
|
567 * bundle and each class name under which the <code>ServiceReference</code>
|
|
568 * object was registered. For any given <code>ServiceReference</code>
|
|
569 * object, if any call to
|
|
570 * {@link ServiceReference#isAssignableTo(Bundle, String)} returns
|
|
571 * <code>false</code>, then it is removed from the set of
|
|
572 * <code>ServiceReference</code> objects.
|
|
573 * <li>An array of the remaining <code>ServiceReference</code> objects is
|
|
574 * returned.
|
|
575 * </ol>
|
|
576 *
|
|
577 * @param clazz The class name with which the service was registered or
|
|
578 * <code>null</code> for all services.
|
|
579 * @param filter The filter criteria.
|
|
580 * @return An array of <code>ServiceReference</code> objects or
|
|
581 * <code>null</code> if no services are registered which satisfy
|
|
582 * the search.
|
|
583 * @throws InvalidSyntaxException If <code>filter</code> contains an
|
|
584 * invalid filter string that cannot be parsed.
|
|
585 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
586 * longer valid.
|
|
587 */
|
|
588 public ServiceReference[] getServiceReferences(String clazz,
|
|
589 String filter);
|
|
590
|
|
591 /**
|
|
592 * Returns an array of <code>ServiceReference</code> objects. The returned
|
|
593 * array of <code>ServiceReference</code> objects contains services that
|
|
594 * were registered under the specified class and match the specified filter
|
|
595 * criteria.
|
|
596 *
|
|
597 * <p>
|
|
598 * The list is valid at the time of the call to this method, however since
|
|
599 * the Framework is a very dynamic environment, services can be modified or
|
|
600 * unregistered at anytime.
|
|
601 *
|
|
602 * <p>
|
|
603 * <code>filter</code> is used to select the registered service whose
|
|
604 * properties objects contain keys and values which satisfy the filter. See
|
|
605 * {@link Filter} for a description of the filter string syntax.
|
|
606 *
|
|
607 * <p>
|
|
608 * If <code>filter</code> is <code>null</code>, all registered services
|
|
609 * are considered to match the filter. If <code>filter</code> cannot be
|
|
610 * parsed, an {@link InvalidSyntaxException} will be thrown with a human
|
|
611 * readable message where the filter became unparsable.
|
|
612 *
|
|
613 * <p>
|
|
614 * The following steps are required to select a set of
|
|
615 * <code>ServiceReference</code> objects:
|
|
616 * <ol>
|
|
617 * <li>If the filter string is not <code>null</code>, the filter string
|
|
618 * is parsed and the set <code>ServiceReference</code> objects of
|
|
619 * registered services that satisfy the filter is produced. If the filter
|
|
620 * string is <code>null</code>, then all registered services are
|
|
621 * considered to satisfy the filter.
|
|
622 * <li>If the Java Runtime Environment supports permissions, the set of
|
|
623 * <code>ServiceReference</code> objects produced by the previous step is
|
|
624 * reduced by checking that the caller has the
|
|
625 * <code>ServicePermission</code> to get at least one of the class names
|
|
626 * under which the service was registered. If the caller does not have the
|
|
627 * correct permission for a particular <code>ServiceReference</code>
|
|
628 * object, then it is removed from the set.
|
|
629 * <li>If <code>clazz</code> is not <code>null</code>, the set is
|
|
630 * further reduced to those services that are an <code>instanceof</code>
|
|
631 * and were registered under the specified class. The complete list of
|
|
632 * classes of which a service is an instance and which were specified when
|
|
633 * the service was registered is available from the service's
|
|
634 * {@link Constants#OBJECTCLASS} property.
|
|
635 * <li>An array of the remaining <code>ServiceReference</code> objects is
|
|
636 * returned.
|
|
637 * </ol>
|
|
638 *
|
|
639 * @param clazz The class name with which the service was registered or
|
|
640 * <code>null</code> for all services.
|
|
641 * @param filter The filter criteria.
|
|
642 * @return An array of <code>ServiceReference</code> objects or
|
|
643 * <code>null</code> if no services are registered which satisfy
|
|
644 * the search.
|
|
645 * @throws InvalidSyntaxException If <code>filter</code> contains an
|
|
646 * invalid filter string that cannot be parsed.
|
|
647 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
648 * longer valid.
|
|
649 * @since 1.3
|
|
650 */
|
|
651 public ServiceReference[] getAllServiceReferences(String clazz,
|
|
652 String filter);
|
|
653
|
|
654 /**
|
|
655 * Returns a <code>ServiceReference</code> object for a service that
|
|
656 * implements and was registered under the specified class.
|
|
657 *
|
|
658 * <p>
|
|
659 * This <code>ServiceReference</code> object is valid at the time of the
|
|
660 * call to this method, however as the Framework is a very dynamic
|
|
661 * environment, services can be modified or unregistered at anytime.
|
|
662 *
|
|
663 * <p>
|
|
664 * This method is the same as calling
|
|
665 * {@link BundleContext#getServiceReferences(String, String)} with a
|
|
666 * <code>null</code> filter string. It is provided as a convenience for
|
|
667 * when the caller is interested in any service that implements the
|
|
668 * specified class.
|
|
669 * <p>
|
|
670 * If multiple such services exist, the service with the highest ranking (as
|
|
671 * specified in its {@link Constants#SERVICE_RANKING} property) is returned.
|
|
672 * <p>
|
|
673 * If there is a tie in ranking, the service with the lowest service ID (as
|
|
674 * specified in its {@link Constants#SERVICE_ID} property); that is, the
|
|
675 * service that was registered first is returned.
|
|
676 *
|
|
677 * @param clazz The class name with which the service was registered.
|
|
678 * @return A <code>ServiceReference</code> object, or <code>null</code>
|
|
679 * if no services are registered which implement the named class.
|
|
680 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
681 * longer valid.
|
|
682 * @see #getServiceReferences(String, String)
|
|
683 */
|
|
684 public ServiceReference getServiceReference(String clazz);
|
|
685
|
|
686 /**
|
|
687 * Returns the specified service object for a service.
|
|
688 * <p>
|
|
689 * A bundle's use of a service is tracked by the bundle's use count of that
|
|
690 * service. Each time a service's service object is returned by
|
|
691 * {@link #getService(ServiceReference)} the context bundle's use count for
|
|
692 * that service is incremented by one. Each time the service is released by
|
|
693 * {@link #ungetService(ServiceReference)} the context bundle's use count
|
|
694 * for that service is decremented by one.
|
|
695 * <p>
|
|
696 * When a bundle's use count for a service drops to zero, the bundle should
|
|
697 * no longer use that service.
|
|
698 *
|
|
699 * <p>
|
|
700 * This method will always return <code>null</code> when the service
|
|
701 * associated with this <code>reference</code> has been unregistered.
|
|
702 *
|
|
703 * <p>
|
|
704 * The following steps are required to get the service object:
|
|
705 * <ol>
|
|
706 * <li>If the service has been unregistered, <code>null</code> is
|
|
707 * returned.
|
|
708 * <li>The context bundle's use count for this service is incremented by
|
|
709 * one.
|
|
710 * <li>If the context bundle's use count for the service is currently one
|
|
711 * and the service was registered with an object implementing the
|
|
712 * <code>ServiceFactory</code> interface, the
|
|
713 * {@link ServiceFactory#getService(Bundle, ServiceRegistration)} method is
|
|
714 * called to create a service object for the context bundle. This service
|
|
715 * object is cached by the Framework. While the context bundle's use count
|
|
716 * for the service is greater than zero, subsequent calls to get the
|
|
717 * services's service object for the context bundle will return the cached
|
|
718 * service object. <br>
|
|
719 * If the service object returned by the <code>ServiceFactory</code>
|
|
720 * object is not an <code>instanceof</code> all the classes named when the
|
|
721 * service was registered or the <code>ServiceFactory</code> object throws
|
|
722 * an exception, <code>null</code> is returned and a Framework event of
|
|
723 * type {@link FrameworkEvent#ERROR} is fired.
|
|
724 * <li>The service object for the service is returned.
|
|
725 * </ol>
|
|
726 *
|
|
727 * @param reference A reference to the service.
|
|
728 * @return A service object for the service associated with
|
|
729 * <code>reference</code> or <code>null</code> if the service is
|
|
730 * not registered or does not implement the classes under which it
|
|
731 * was registered in the case of a <code>ServiceFactory</code>.
|
|
732 * @throws java.lang.SecurityException If the caller does not have the
|
|
733 * <code>ServicePermission</code> to get the service using at
|
|
734 * least one of the named classes the service was registered under
|
|
735 * and the Java Runtime Environment supports permissions.
|
|
736 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
737 * longer valid.
|
|
738 * @see #ungetService(ServiceReference)
|
|
739 * @see ServiceFactory
|
|
740 */
|
|
741 public Object getService(ServiceReference reference);
|
|
742
|
|
743 /**
|
|
744 * Releases the service object referenced by the specified
|
|
745 * <code>ServiceReference</code> object. If the context bundle's use count
|
|
746 * for the service is zero, this method returns <code>false</code>.
|
|
747 * Otherwise, the context bundle's use count for the service is decremented
|
|
748 * by one.
|
|
749 *
|
|
750 * <p>
|
|
751 * The service's service object should no longer be used and all references
|
|
752 * to it should be destroyed when a bundle's use count for the service drops
|
|
753 * to zero.
|
|
754 *
|
|
755 * <p>
|
|
756 * The following steps are required to unget the service object:
|
|
757 * <ol>
|
|
758 * <li>If the context bundle's use count for the service is zero or the
|
|
759 * service has been unregistered, <code>false</code> is returned.
|
|
760 * <li>The context bundle's use count for this service is decremented by
|
|
761 * one.
|
|
762 * <li>If the context bundle's use count for the service is currently zero
|
|
763 * and the service was registered with a <code>ServiceFactory</code>
|
|
764 * object, the
|
|
765 * {@link ServiceFactory#ungetService(Bundle, ServiceRegistration, Object)}
|
|
766 * method is called to release the service object for the context bundle.
|
|
767 * <li><code>true</code> is returned.
|
|
768 * </ol>
|
|
769 *
|
|
770 * @param reference A reference to the service to be released.
|
|
771 * @return <code>false</code> if the context bundle's use count for the
|
|
772 * service is zero or if the service has been unregistered;
|
|
773 * <code>true</code> otherwise.
|
|
774 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
775 * longer valid.
|
|
776 * @see #getService
|
|
777 * @see ServiceFactory
|
|
778 */
|
|
779 public bool ungetService(ServiceReference reference);
|
|
780
|
|
781 /**
|
|
782 * Creates a <code>File</code> object for a file in the persistent storage
|
|
783 * area provided for the bundle by the Framework. This method will return
|
|
784 * <code>null</code> if the platform does not have file system support.
|
|
785 *
|
|
786 * <p>
|
|
787 * A <code>File</code> object for the base directory of the persistent
|
|
788 * storage area provided for the context bundle by the Framework can be
|
|
789 * obtained by calling this method with an empty string as
|
|
790 * <code>filename</code>.
|
|
791 *
|
|
792 * <p>
|
|
793 * If the Java Runtime Environment supports permissions, the Framework will
|
|
794 * ensure that the bundle has the <code>java.io.FilePermission</code> with
|
|
795 * actions <code>read</code>,<code>write</code>,<code>delete</code>
|
|
796 * for all files (recursively) in the persistent storage area provided for
|
|
797 * the context bundle.
|
|
798 *
|
|
799 * @param filename A relative name to the file to be accessed.
|
|
800 * @return A <code>File</code> object that represents the requested file
|
|
801 * or <code>null</code> if the platform does not have file system
|
|
802 * support.
|
|
803 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
804 * longer valid.
|
|
805 */
|
|
806 public File getDataFile(String filename);
|
|
807
|
|
808 /**
|
|
809 * Creates a <code>Filter</code> object. This <code>Filter</code> object
|
|
810 * may be used to match a <code>ServiceReference</code> object or a
|
|
811 * <code>Dictionary</code> object.
|
|
812 *
|
|
813 * <p>
|
|
814 * If the filter cannot be parsed, an {@link InvalidSyntaxException} will be
|
|
815 * thrown with a human readable message where the filter became unparsable.
|
|
816 *
|
|
817 * @param filter The filter string.
|
|
818 * @return A <code>Filter</code> object encapsulating the filter string.
|
|
819 * @throws InvalidSyntaxException If <code>filter</code> contains an
|
|
820 * invalid filter string that cannot be parsed.
|
|
821 * @throws NullPointerException If <code>filter</code> is null.
|
|
822 * @throws java.lang.IllegalStateException If this BundleContext is no
|
|
823 * longer valid.
|
|
824 *
|
|
825 * @since 1.1
|
|
826 * @see "Framework specification for a description of the filter string syntax."
|
|
827 * @see FrameworkUtil#createFilter(String)
|
|
828 */
|
|
829 public Filter createFilter(String filter);
|
|
830 }
|