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1 /*******************************************************************************
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2 * Copyright (c) 2005, 2008 IBM Corporation and others.
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3 * All rights reserved. This program and the accompanying materials
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4 * are made available under the terms of the Eclipse Public License v1.0
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5 * which accompanies this distribution, and is available at
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6 * http://www.eclipse.org/legal/epl-v10.html
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7 *
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8 * Contributors:
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9 * IBM Corporation - initial API and implementation
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10 * Matthew Hall - bug 118516
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11 *******************************************************************************/
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12 module org.eclipse.core.internal.databinding.observable.tree.TreePath;
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13
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14 import java.lang.all;
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15
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16 import org.eclipse.core.runtime.Assert;
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17
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18 /**
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19 * A tree path denotes a model element in a tree viewer. Tree path objects have
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20 * value semantics. A model element is represented by a path of elements in the
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21 * tree from the root element to the leaf element.
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22 * <p>
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23 * Clients may instantiate this class. Not intended to be subclassed.
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24 * </p>
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25 *
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26 * @since 3.2
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27 */
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28 public final class TreePath {
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29
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30 /**
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31 * Constant for representing an empty tree path.
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32 */
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85
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33 public static TreePath EMPTY;
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34 static this(){
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35 EMPTY = new TreePath(new Object[0]);
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36 }
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78
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37
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38 private Object[] segments;
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39
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40 private int hash;
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41
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42 /**
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43 * Constructs a path identifying a leaf node in a tree.
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44 *
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45 * @param segments
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46 * path of elements to a leaf node in a tree, starting with the
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47 * root element
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48 */
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49 public this(Object[] segments) {
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85
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50 Assert.isTrue(segments !is null, "Segments array cannot be null"); //$NON-NLS-1$
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78
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51 this.segments = new Object[segments.length];
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52 for (int i = 0; i < segments.length; i++) {
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53 Assert.isNotNull(segments[i], "Segments array cannot contain null"); //$NON-NLS-1$
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54 this.segments[i] = segments[i];
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55 }
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56 }
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57
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58 /**
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59 * Returns the element at the specified index in this path.
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60 *
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61 * @param index
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62 * index of element to return
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63 * @return element at the specified index
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64 */
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65 public Object getSegment(int index) {
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66 return segments[index];
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67 }
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68
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69 /**
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70 * Returns the number of elements in this path.
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71 *
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72 * @return the number of elements in this path
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73 */
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74 public int getSegmentCount() {
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75 return segments.length;
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76 }
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77
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78 /**
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79 * Returns the first element in this path.
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80 *
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81 * @return the first element in this path
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82 */
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83 public Object getFirstSegment() {
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84 if (segments.length is 0) {
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85 return null;
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86 }
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87 return segments[0];
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88 }
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89
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90 /**
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91 * Returns the last element in this path.
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92 *
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93 * @return the last element in this path
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94 */
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95 public Object getLastSegment() {
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96 if (segments.length is 0) {
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97 return null;
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98 }
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99 return segments[segments.length - 1];
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100 }
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101
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102 /*
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103 * (non-Javadoc)
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104 *
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105 * @see java.lang.Object#equals(java.lang.Object)
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106 */
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85
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107 public override equals_t opEquals(Object other) {
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78
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108 if (!( null !is cast(TreePath)other )) {
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109 return false;
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110 }
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111 TreePath otherPath = cast(TreePath) other;
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112 if (segments.length !is otherPath.segments.length) {
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113 return false;
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114 }
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115 for (int i = 0; i < segments.length; i++) {
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85
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116 if (!segments[i].opEquals(otherPath.segments[i])) {
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117 return false;
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118 }
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119 }
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120 return true;
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121 }
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122
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85
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123 public hash_t toHash() {
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78
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124 if (hash is 0) {
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125 for (int i = 0; i < segments.length; i++) {
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126 hash += segments[i].toHash();
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78
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127 }
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128 }
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129 return hash;
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130 }
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131
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132 /**
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133 * Returns whether this path starts with the same segments as the given
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134 * path, using the given comparer to compare segments.
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135 *
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136 * @param treePath
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137 * path to compare to
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138 * @return whether the given path is a prefix of this path, or the same as
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139 * this path
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140 */
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141 public bool startsWith(TreePath treePath) {
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142 int thisSegmentCount = getSegmentCount();
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143 int otherSegmentCount = treePath.getSegmentCount();
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144 if (otherSegmentCount is thisSegmentCount) {
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85
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145 return cast(bool)opEquals(treePath);
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78
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146 }
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147 if (otherSegmentCount > thisSegmentCount) {
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148 return false;
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149 }
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150 for (int i = 0; i < otherSegmentCount; i++) {
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151 Object otherSegment = treePath.getSegment(i);
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85
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152 if (!otherSegment.opEquals(segments[i])) {
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153 return false;
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154 }
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155 }
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156 return true;
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157 }
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158
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159 /**
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160 * Returns a copy of this tree path with one segment removed from the end,
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161 * or <code>null</code> if this tree path has no segments.
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162 * @return a tree path
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163 */
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164 public TreePath getParentPath() {
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165 int segmentCount = getSegmentCount();
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166 if (segmentCount <= 1) {
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167 return null;
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168 }
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169 Object[] parentSegments = new Object[segmentCount - 1];
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170 System.arraycopy(segments, 0, parentSegments, 0, segmentCount - 1);
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171 return new TreePath(parentSegments);
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172 }
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173
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174 /**
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175 * Returns a copy of this tree path with the given segment added at the end.
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176 * @param newSegment
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177 * @return a tree path
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178 */
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179 public TreePath createChildPath(Object newSegment) {
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180 int segmentCount = getSegmentCount();
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181 Object[] childSegments = new Object[segmentCount + 1];
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182 if(segmentCount>0) {
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183 System.arraycopy(segments, 0, childSegments, 0, segmentCount);
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184 }
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185 childSegments[segmentCount] = newSegment;
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186 return new TreePath(childSegments);
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187 }
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188 }
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