Mercurial > projects > dwt2
view org.eclipse.osgi/osgi/src/org/osgi/framework/BundleContext.d @ 86:12b890a6392a
Work on databinding
author | Frank Benoit <benoit@tionex.de> |
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date | Sat, 18 Apr 2009 13:58:35 +0200 |
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children | bbe49769ec18 |
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/* * $Header: /cvshome/build/org.osgi.framework/src/org/osgi/framework/BundleContext.java,v 1.22 2007/02/21 16:49:05 hargrave Exp $ * * Copyright (c) OSGi Alliance (2000, 2007). All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ module org.osgi.framework.BundleContext; import org.osgi.framework.Bundle; import org.osgi.framework.BundleListener; import org.osgi.framework.ServiceListener; import org.osgi.framework.FrameworkListener; import org.osgi.framework.ServiceReference; import org.osgi.framework.ServiceRegistration; import org.osgi.framework.Filter; import java.lang.all; import java.io.File; import java.io.InputStream; import java.util.Dictionary; /** * A bundle's execution context within the Framework. The context is used to * grant access to other methods so that this bundle can interact with the * Framework. * * <p> * <code>BundleContext</code> methods allow a bundle to: * <ul> * <li>Subscribe to events published by the Framework. * <li>Register service objects with the Framework service registry. * <li>Retrieve <code>ServiceReferences</code> from the Framework service * registry. * <li>Get and release service objects for a referenced service. * <li>Install new bundles in the Framework. * <li>Get the list of bundles installed in the Framework. * <li>Get the {@link Bundle} object for a bundle. * <li>Create <code>File</code> objects for files in a persistent storage * area provided for the bundle by the Framework. * </ul> * * <p> * A <code>BundleContext</code> object will be created and provided to the * bundle associated with this context when it is started using the * {@link BundleActivator#start} method. The same <code>BundleContext</code> * object will be passed to the bundle associated with this context when it is * stopped using the {@link BundleActivator#stop} method. A * <code>BundleContext</code> object is generally for the private use of its * associated bundle and is not meant to be shared with other bundles in the * OSGi environment. * * <p> * The <code>Bundle</code> object associated with a <code>BundleContext</code> * object is called the <em>context bundle</em>. * * <p> * The <code>BundleContext</code> object is only valid during the execution of * its context bundle; that is, during the period from when the context bundle * is in the <code>STARTING</code>, <code>STOPPING</code>, and * <code>ACTIVE</code> bundle states. If the <code>BundleContext</code> * object is used subsequently, an <code>IllegalStateException</code> must be * thrown. The <code>BundleContext</code> object must never be reused after * its context bundle is stopped. * * <p> * The Framework is the only entity that can create <code>BundleContext</code> * objects and they are only valid within the Framework that created them. * * @ThreadSafe * @version $Revision: 1.22 $ */ public interface BundleContext { /** * Returns the value of the specified property. If the key is not found in * the Framework properties, the system properties are then searched. The * method returns <code>null</code> if the property is not found. * * <p> * The Framework defines the following standard property keys: * </p> * <ul> * <li>{@link Constants#FRAMEWORK_VERSION} - The OSGi Framework version. * </li> * <li>{@link Constants#FRAMEWORK_VENDOR} - The Framework implementation * vendor.</li> * <li>{@link Constants#FRAMEWORK_LANGUAGE} - The language being used. See * ISO 639 for possible values.</li> * <li>{@link Constants#FRAMEWORK_OS_NAME} - The host computer operating * system.</li> * <li>{@link Constants#FRAMEWORK_OS_VERSION} - The host computer * operating system version number.</li> * <li>{@link Constants#FRAMEWORK_PROCESSOR} - The host computer processor * name.</li> * </ul> * <p> * All bundles must have permission to read these properties. * * <p> * Note: The last four standard properties are used by the * {@link Constants#BUNDLE_NATIVECODE} <code>Manifest</code> header's * matching algorithm for selecting native language code. * * @param key The name of the requested property. * @return The value of the requested property, or <code>null</code> if * the property is undefined. * @throws java.lang.SecurityException If the caller does not have the * appropriate <code>PropertyPermission</code> to read the * property, and the Java Runtime Environment supports permissions. */ public String getProperty(String key); /** * Returns the <code>Bundle</code> object associated with this * <code>BundleContext</code>. This bundle is called the context bundle. * * @return The <code>Bundle</code> object associated with this * <code>BundleContext</code>. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. */ public Bundle getBundle(); /** * Installs a bundle from the specified location string. A bundle is * obtained from <code>location</code> as interpreted by the Framework in * an implementation dependent manner. * <p> * Every installed bundle is uniquely identified by its location string, * typically in the form of a URL. * * <p> * The following steps are required to install a bundle: * <ol> * <li>If a bundle containing the same location string is already * installed, the <code>Bundle</code> object for that bundle is returned. * * <li>The bundle's content is read from the location string. If this * fails, a {@link BundleException} is thrown. * * <li>The bundle's <code>Bundle-NativeCode</code> dependencies are * resolved. If this fails, a <code>BundleException</code> is thrown. * * <li>The bundle's associated resources are allocated. The associated * resources minimally consist of a unique identifier and a persistent * storage area if the platform has file system support. If this step fails, * a <code>BundleException</code> is thrown. * * <li>If the bundle has declared an Bundle-RequiredExecutionEnvironment * header, then the listed execution environments must be verified against * the installed execution environments. If none of the listed execution * environments match an installed execution environment, a * <code>BundleException</code> must be thrown. * * <li>The bundle's state is set to <code>INSTALLED</code>. * * <li>A bundle event of type {@link BundleEvent#INSTALLED} is fired. * * <li>The <code>Bundle</code> object for the newly or previously * installed bundle is returned. * </ol> * * <b>Postconditions, no exceptions thrown </b> * <ul> * <li><code>getState()</code> in {<code>INSTALLED</code>,<code>RESOLVED</code>}. * <li>Bundle has a unique ID. * </ul> * <b>Postconditions, when an exception is thrown </b> * <ul> * <li>Bundle is not installed and no trace of the bundle exists. * </ul> * * @param location The location identifier of the bundle to install. * @return The <code>Bundle</code> object of the installed bundle. * @throws BundleException If the installation failed. * @throws java.lang.SecurityException If the caller does not have the * appropriate <code>AdminPermission[installed bundle,LIFECYCLE]</code>, and the * Java Runtime Environment supports permissions. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. */ public Bundle installBundle(String location); /** * Installs a bundle from the specified <code>InputStream</code> object. * * <p> * This method performs all of the steps listed in * <code>BundleContext.installBundle(String location)</code>, except that * the bundle's content will be read from the <code>InputStream</code> * object. The location identifier string specified will be used as the * identity of the bundle. * * <p> * This method must always close the <code>InputStream</code> object, even * if an exception is thrown. * * @param location The location identifier of the bundle to install. * @param input The <code>InputStream</code> object from which this bundle * will be read. * @return The <code>Bundle</code> object of the installed bundle. * @throws BundleException If the provided stream cannot be read or the * installation failed. * @throws java.lang.SecurityException If the caller does not have the * appropriate <code>AdminPermission[installed bundle,LIFECYCLE]</code>, and the * Java Runtime Environment supports permissions. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @see #installBundle(java.lang.String) */ public Bundle installBundle(String location, InputStream input); /** * Returns the bundle with the specified identifier. * * @param id The identifier of the bundle to retrieve. * @return A <code>Bundle</code> object or <code>null</code> if the * identifier does not match any installed bundle. */ public Bundle getBundle(long id); /** * Returns a list of all installed bundles. * <p> * This method returns a list of all bundles installed in the OSGi * environment at the time of the call to this method. However, since the * Framework is a very dynamic environment, bundles can be installed or * uninstalled at anytime. * * @return An array of <code>Bundle</code> objects, one object per * installed bundle. */ public Bundle[] getBundles(); /** * Adds the specified <code>ServiceListener</code> object with the * specified <code>filter</code> to the context bundle's list of * listeners. See {@link Filter} for a description of the filter syntax. * <code>ServiceListener</code> objects are notified when a service has a * lifecycle state change. * * <p> * If the context bundle's list of listeners already contains a listener * <code>l</code> such that <code>(l==listener)</code>, then this * method replaces that listener's filter (which may be <code>null</code>) * with the specified one (which may be <code>null</code>). * * <p> * The listener is called if the filter criteria is met. To filter based * upon the class of the service, the filter should reference the * {@link Constants#OBJECTCLASS} property. If <code>filter</code> is * <code>null</code>, all services are considered to match the filter. * * <p> * When using a <code>filter</code>, it is possible that the * <code>ServiceEvent</code>s for the complete lifecycle of a service * will not be delivered to the listener. For example, if the * <code>filter</code> only matches when the property <code>x</code> has * the value <code>1</code>, the listener will not be called if the * service is registered with the property <code>x</code> not set to the * value <code>1</code>. Subsequently, when the service is modified * setting property <code>x</code> to the value <code>1</code>, the * filter will match and the listener will be called with a * <code>ServiceEvent</code> of type <code>MODIFIED</code>. Thus, the * listener will not be called with a <code>ServiceEvent</code> of type * <code>REGISTERED</code>. * * <p> * If the Java Runtime Environment supports permissions, the * <code>ServiceListener</code> object will be notified of a service event * only if the bundle that is registering it has the * <code>ServicePermission</code> to get the service using at least one of * the named classes the service was registered under. * * @param listener The <code>ServiceListener</code> object to be added. * @param filter The filter criteria. * * @throws InvalidSyntaxException If <code>filter</code> contains an * invalid filter string that cannot be parsed. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * * @see ServiceEvent * @see ServiceListener * @see ServicePermission */ public void addServiceListener(ServiceListener listener, String filter); /** * Adds the specified <code>ServiceListener</code> object to the context * bundle's list of listeners. * * <p> * This method is the same as calling * <code>BundleContext.addServiceListener(ServiceListener listener, * String filter)</code> * with <code>filter</code> set to <code>null</code>. * * @param listener The <code>ServiceListener</code> object to be added. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * * @see #addServiceListener(ServiceListener, String) */ public void addServiceListener(ServiceListener listener); /** * Removes the specified <code>ServiceListener</code> object from the * context bundle's list of listeners. * * <p> * If <code>listener</code> is not contained in this context bundle's list * of listeners, this method does nothing. * * @param listener The <code>ServiceListener</code> to be removed. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. */ public void removeServiceListener(ServiceListener listener); /** * Adds the specified <code>BundleListener</code> object to the context * bundle's list of listeners if not already present. BundleListener objects * are notified when a bundle has a lifecycle state change. * * <p> * If the context bundle's list of listeners already contains a listener * <code>l</code> such that <code>(l==listener)</code>, this method * does nothing. * * @param listener The <code>BundleListener</code> to be added. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @throws java.lang.SecurityException If listener is a * <code>SynchronousBundleListener</code> and the caller does not * have the appropriate <code>AdminPermission[context bundle,LISTENER]</code>, * and the Java Runtime Environment supports permissions. * * @see BundleEvent * @see BundleListener */ public void addBundleListener(BundleListener listener); /** * Removes the specified <code>BundleListener</code> object from the * context bundle's list of listeners. * * <p> * If <code>listener</code> is not contained in the context bundle's list * of listeners, this method does nothing. * * @param listener The <code>BundleListener</code> object to be removed. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @throws java.lang.SecurityException If listener is a * <code>SynchronousBundleListener</code> and the caller does not * have the appropriate <code>AdminPermission[context bundle,LISTENER]</code>, * and the Java Runtime Environment supports permissions. */ public void removeBundleListener(BundleListener listener); /** * Adds the specified <code>FrameworkListener</code> object to the context * bundle's list of listeners if not already present. FrameworkListeners are * notified of general Framework events. * * <p> * If the context bundle's list of listeners already contains a listener * <code>l</code> such that <code>(l==listener)</code>, this method * does nothing. * * @param listener The <code>FrameworkListener</code> object to be added. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * * @see FrameworkEvent * @see FrameworkListener */ public void addFrameworkListener(FrameworkListener listener); /** * Removes the specified <code>FrameworkListener</code> object from the * context bundle's list of listeners. * * <p> * If <code>listener</code> is not contained in the context bundle's list * of listeners, this method does nothing. * * @param listener The <code>FrameworkListener</code> object to be * removed. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. */ public void removeFrameworkListener(FrameworkListener listener); /** * Registers the specified service object with the specified properties * under the specified class names into the Framework. A * <code>ServiceRegistration</code> object is returned. The * <code>ServiceRegistration</code> object is for the private use of the * bundle registering the service and should not be shared with other * bundles. The registering bundle is defined to be the context bundle. * Other bundles can locate the service by using either the * {@link #getServiceReferences} or {@link #getServiceReference} method. * * <p> * A bundle can register a service object that implements the * {@link ServiceFactory} interface to have more flexibility in providing * service objects to other bundles. * * <p> * The following steps are required to register a service: * <ol> * <li>If <code>service</code> is not a <code>ServiceFactory</code>, * an <code>IllegalArgumentException</code> is thrown if * <code>service</code> is not an <code>instanceof</code> all the * classes named. * <li>The Framework adds these service properties to the specified * <code>Dictionary</code> (which may be <code>null</code>): a property * named {@link Constants#SERVICE_ID} identifying the registration number of * the service and a property named {@link Constants#OBJECTCLASS} containing * all the specified classes. If any of these properties have already been * specified by the registering bundle, their values will be overwritten by * the Framework. * <li>The service is added to the Framework service registry and may now * be used by other bundles. * <li>A service event of type {@link ServiceEvent#REGISTERED} is * fired. * <li>A <code>ServiceRegistration</code> object for this registration is * returned. * </ol> * * @param clazzes The class names under which the service can be located. * The class names in this array will be stored in the service's * properties under the key {@link Constants#OBJECTCLASS}. * @param service The service object or a <code>ServiceFactory</code> * object. * @param properties The properties for this service. The keys in the * properties object must all be <code>String</code> objects. See * {@link Constants} for a list of standard service property keys. * Changes should not be made to this object after calling this * method. To update the service's properties the * {@link ServiceRegistration#setProperties} method must be called. * The set of properties may be <code>null</code> if the service * has no properties. * * @return A <code>ServiceRegistration</code> object for use by the bundle * registering the service to update the service's properties or to * unregister the service. * * @throws java.lang.IllegalArgumentException If one of the following is * true: * <ul> * <li><code>service</code> is <code>null</code>. * <li><code>service</code> is not a <code>ServiceFactory</code> * object and is not an instance of all the named classes in * <code>clazzes</code>. * <li><code>properties</code> contains case variants of the same * key name. * </ul> * * @throws java.lang.SecurityException If the caller does not have the * <code>ServicePermission</code> to register the service for all * the named classes and the Java Runtime Environment supports * permissions. * * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * * @see ServiceRegistration * @see ServiceFactory */ public ServiceRegistration registerService(String[] clazzes, Object service, Dictionary properties); /** * Registers the specified service object with the specified properties * under the specified class name with the Framework. * * <p> * This method is otherwise identical to * {@link #registerService(java.lang.String[], java.lang.Object, * java.util.Dictionary)} and is provided as a convenience when * <code>service</code> will only be registered under a single class name. * Note that even in this case the value of the service's * {@link Constants#OBJECTCLASS} property will be an array of strings, * rather than just a single string. * * @param clazz The class name under which the service can be located. * @param service The service object or a <code>ServiceFactory</code> * object. * @param properties The properties for this service. * * @return A <code>ServiceRegistration</code> object for use by the bundle * registering the service to update the service's properties or to * unregister the service. * * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @see #registerService(java.lang.String[], java.lang.Object, * java.util.Dictionary) */ public ServiceRegistration registerService(String clazz, Object service, Dictionary properties); /** * Returns an array of <code>ServiceReference</code> objects. The returned * array of <code>ServiceReference</code> objects contains services that * were registered under the specified class, match the specified filter * criteria, and the packages for the class names under which the services * were registered match the context bundle's packages as defined in * {@link ServiceReference#isAssignableTo(Bundle, String)}. * * <p> * The list is valid at the time of the call to this method, however since * the Framework is a very dynamic environment, services can be modified or * unregistered at anytime. * * <p> * <code>filter</code> is used to select the registered service whose * properties objects contain keys and values which satisfy the filter. See * {@link Filter} for a description of the filter string syntax. * * <p> * If <code>filter</code> is <code>null</code>, all registered services * are considered to match the filter. If <code>filter</code> cannot be * parsed, an {@link InvalidSyntaxException} will be thrown with a human * readable message where the filter became unparsable. * * <p> * The following steps are required to select a set of * <code>ServiceReference</code> objects: * <ol> * <li>If the filter string is not <code>null</code>, the filter string * is parsed and the set <code>ServiceReference</code> objects of * registered services that satisfy the filter is produced. If the filter * string is <code>null</code>, then all registered services are * considered to satisfy the filter. * <li>If the Java Runtime Environment supports permissions, the set of * <code>ServiceReference</code> objects produced by the previous step is * reduced by checking that the caller has the * <code>ServicePermission</code> to get at least one of the class names * under which the service was registered. If the caller does not have the * correct permission for a particular <code>ServiceReference</code> * object, then it is removed from the set. * <li>If <code>clazz</code> is not <code>null</code>, the set is * further reduced to those services that are an <code>instanceof</code> * and were registered under the specified class. The complete list of * classes of which a service is an instance and which were specified when * the service was registered is available from the service's * {@link Constants#OBJECTCLASS} property. * <li>The set is reduced one final time by cycling through each * <code>ServiceReference</code> object and calling * {@link ServiceReference#isAssignableTo(Bundle, String)} with the context * bundle and each class name under which the <code>ServiceReference</code> * object was registered. For any given <code>ServiceReference</code> * object, if any call to * {@link ServiceReference#isAssignableTo(Bundle, String)} returns * <code>false</code>, then it is removed from the set of * <code>ServiceReference</code> objects. * <li>An array of the remaining <code>ServiceReference</code> objects is * returned. * </ol> * * @param clazz The class name with which the service was registered or * <code>null</code> for all services. * @param filter The filter criteria. * @return An array of <code>ServiceReference</code> objects or * <code>null</code> if no services are registered which satisfy * the search. * @throws InvalidSyntaxException If <code>filter</code> contains an * invalid filter string that cannot be parsed. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. */ public ServiceReference[] getServiceReferences(String clazz, String filter); /** * Returns an array of <code>ServiceReference</code> objects. The returned * array of <code>ServiceReference</code> objects contains services that * were registered under the specified class and match the specified filter * criteria. * * <p> * The list is valid at the time of the call to this method, however since * the Framework is a very dynamic environment, services can be modified or * unregistered at anytime. * * <p> * <code>filter</code> is used to select the registered service whose * properties objects contain keys and values which satisfy the filter. See * {@link Filter} for a description of the filter string syntax. * * <p> * If <code>filter</code> is <code>null</code>, all registered services * are considered to match the filter. If <code>filter</code> cannot be * parsed, an {@link InvalidSyntaxException} will be thrown with a human * readable message where the filter became unparsable. * * <p> * The following steps are required to select a set of * <code>ServiceReference</code> objects: * <ol> * <li>If the filter string is not <code>null</code>, the filter string * is parsed and the set <code>ServiceReference</code> objects of * registered services that satisfy the filter is produced. If the filter * string is <code>null</code>, then all registered services are * considered to satisfy the filter. * <li>If the Java Runtime Environment supports permissions, the set of * <code>ServiceReference</code> objects produced by the previous step is * reduced by checking that the caller has the * <code>ServicePermission</code> to get at least one of the class names * under which the service was registered. If the caller does not have the * correct permission for a particular <code>ServiceReference</code> * object, then it is removed from the set. * <li>If <code>clazz</code> is not <code>null</code>, the set is * further reduced to those services that are an <code>instanceof</code> * and were registered under the specified class. The complete list of * classes of which a service is an instance and which were specified when * the service was registered is available from the service's * {@link Constants#OBJECTCLASS} property. * <li>An array of the remaining <code>ServiceReference</code> objects is * returned. * </ol> * * @param clazz The class name with which the service was registered or * <code>null</code> for all services. * @param filter The filter criteria. * @return An array of <code>ServiceReference</code> objects or * <code>null</code> if no services are registered which satisfy * the search. * @throws InvalidSyntaxException If <code>filter</code> contains an * invalid filter string that cannot be parsed. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @since 1.3 */ public ServiceReference[] getAllServiceReferences(String clazz, String filter); /** * Returns a <code>ServiceReference</code> object for a service that * implements and was registered under the specified class. * * <p> * This <code>ServiceReference</code> object is valid at the time of the * call to this method, however as the Framework is a very dynamic * environment, services can be modified or unregistered at anytime. * * <p> * This method is the same as calling * {@link BundleContext#getServiceReferences(String, String)} with a * <code>null</code> filter string. It is provided as a convenience for * when the caller is interested in any service that implements the * specified class. * <p> * If multiple such services exist, the service with the highest ranking (as * specified in its {@link Constants#SERVICE_RANKING} property) is returned. * <p> * If there is a tie in ranking, the service with the lowest service ID (as * specified in its {@link Constants#SERVICE_ID} property); that is, the * service that was registered first is returned. * * @param clazz The class name with which the service was registered. * @return A <code>ServiceReference</code> object, or <code>null</code> * if no services are registered which implement the named class. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @see #getServiceReferences(String, String) */ public ServiceReference getServiceReference(String clazz); /** * Returns the specified service object for a service. * <p> * A bundle's use of a service is tracked by the bundle's use count of that * service. Each time a service's service object is returned by * {@link #getService(ServiceReference)} the context bundle's use count for * that service is incremented by one. Each time the service is released by * {@link #ungetService(ServiceReference)} the context bundle's use count * for that service is decremented by one. * <p> * When a bundle's use count for a service drops to zero, the bundle should * no longer use that service. * * <p> * This method will always return <code>null</code> when the service * associated with this <code>reference</code> has been unregistered. * * <p> * The following steps are required to get the service object: * <ol> * <li>If the service has been unregistered, <code>null</code> is * returned. * <li>The context bundle's use count for this service is incremented by * one. * <li>If the context bundle's use count for the service is currently one * and the service was registered with an object implementing the * <code>ServiceFactory</code> interface, the * {@link ServiceFactory#getService(Bundle, ServiceRegistration)} method is * called to create a service object for the context bundle. This service * object is cached by the Framework. While the context bundle's use count * for the service is greater than zero, subsequent calls to get the * services's service object for the context bundle will return the cached * service object. <br> * If the service object returned by the <code>ServiceFactory</code> * object is not an <code>instanceof</code> all the classes named when the * service was registered or the <code>ServiceFactory</code> object throws * an exception, <code>null</code> is returned and a Framework event of * type {@link FrameworkEvent#ERROR} is fired. * <li>The service object for the service is returned. * </ol> * * @param reference A reference to the service. * @return A service object for the service associated with * <code>reference</code> or <code>null</code> if the service is * not registered or does not implement the classes under which it * was registered in the case of a <code>ServiceFactory</code>. * @throws java.lang.SecurityException If the caller does not have the * <code>ServicePermission</code> to get the service using at * least one of the named classes the service was registered under * and the Java Runtime Environment supports permissions. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @see #ungetService(ServiceReference) * @see ServiceFactory */ public Object getService(ServiceReference reference); /** * Releases the service object referenced by the specified * <code>ServiceReference</code> object. If the context bundle's use count * for the service is zero, this method returns <code>false</code>. * Otherwise, the context bundle's use count for the service is decremented * by one. * * <p> * The service's service object should no longer be used and all references * to it should be destroyed when a bundle's use count for the service drops * to zero. * * <p> * The following steps are required to unget the service object: * <ol> * <li>If the context bundle's use count for the service is zero or the * service has been unregistered, <code>false</code> is returned. * <li>The context bundle's use count for this service is decremented by * one. * <li>If the context bundle's use count for the service is currently zero * and the service was registered with a <code>ServiceFactory</code> * object, the * {@link ServiceFactory#ungetService(Bundle, ServiceRegistration, Object)} * method is called to release the service object for the context bundle. * <li><code>true</code> is returned. * </ol> * * @param reference A reference to the service to be released. * @return <code>false</code> if the context bundle's use count for the * service is zero or if the service has been unregistered; * <code>true</code> otherwise. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * @see #getService * @see ServiceFactory */ public bool ungetService(ServiceReference reference); /** * Creates a <code>File</code> object for a file in the persistent storage * area provided for the bundle by the Framework. This method will return * <code>null</code> if the platform does not have file system support. * * <p> * A <code>File</code> object for the base directory of the persistent * storage area provided for the context bundle by the Framework can be * obtained by calling this method with an empty string as * <code>filename</code>. * * <p> * If the Java Runtime Environment supports permissions, the Framework will * ensure that the bundle has the <code>java.io.FilePermission</code> with * actions <code>read</code>,<code>write</code>,<code>delete</code> * for all files (recursively) in the persistent storage area provided for * the context bundle. * * @param filename A relative name to the file to be accessed. * @return A <code>File</code> object that represents the requested file * or <code>null</code> if the platform does not have file system * support. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. */ public File getDataFile(String filename); /** * Creates a <code>Filter</code> object. This <code>Filter</code> object * may be used to match a <code>ServiceReference</code> object or a * <code>Dictionary</code> object. * * <p> * If the filter cannot be parsed, an {@link InvalidSyntaxException} will be * thrown with a human readable message where the filter became unparsable. * * @param filter The filter string. * @return A <code>Filter</code> object encapsulating the filter string. * @throws InvalidSyntaxException If <code>filter</code> contains an * invalid filter string that cannot be parsed. * @throws NullPointerException If <code>filter</code> is null. * @throws java.lang.IllegalStateException If this BundleContext is no * longer valid. * * @since 1.1 * @see "Framework specification for a description of the filter string syntax." * @see FrameworkUtil#createFilter(String) */ public Filter createFilter(String filter); }