1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.configuration2.tree.xpath; 18 19 import org.apache.commons.configuration2.tree.NodeHandler; 20 import org.apache.commons.configuration2.tree.QueryResult; 21 import org.apache.commons.jxpath.ri.Compiler; 22 import org.apache.commons.jxpath.ri.QName; 23 import org.apache.commons.jxpath.ri.compiler.NodeTest; 24 import org.apache.commons.jxpath.ri.compiler.NodeTypeTest; 25 import org.apache.commons.jxpath.ri.model.NodePointer; 26 27 /** 28 * <p> 29 * A specialized {@code NodePointer} implementation for the attributes of a configuration node. 30 * </p> 31 * 32 * @param <T> the type of the nodes this pointer deals with 33 * @since 2.0 34 */ 35 final class ConfigurationAttributePointer<T> extends NodePointer { 36 /** 37 * The serial version UID. 38 */ 39 private static final long serialVersionUID = 5504551041716043748L; 40 41 /** Stores information about the represented attribute. */ 42 private final QueryResult<T> attributeResult; 43 44 /** 45 * Creates a new instance of {@code ConfigurationAttributePointer}. 46 * 47 * @param parent the parent node pointer 48 * @param attrName the name of the managed attribute 49 */ 50 public ConfigurationAttributePointer(final ConfigurationNodePointer<T> parent, final String attrName) { 51 super(parent); 52 attributeResult = QueryResult.createAttributeResult(parent.getConfigurationNode(), attrName); 53 } 54 55 /** 56 * Compares two child node pointers. Attributes do not have any children, so this is just a dummy implementation. 57 * 58 * @param p1 the first pointer 59 * @param p2 the second pointer 60 * @return the order of these pointers 61 */ 62 @Override 63 public int compareChildNodePointers(final NodePointer p1, final NodePointer p2) { 64 return 0; 65 } 66 67 /** 68 * Gets the base value. We return the value. 69 * 70 * @return the base value 71 */ 72 @Override 73 public Object getBaseValue() { 74 return getValue(); 75 } 76 77 /** 78 * Gets the immediate node. This is actually a {@link QueryResult} object describing the represented attribute. 79 * 80 * @return the immediate node 81 */ 82 @Override 83 public Object getImmediateNode() { 84 return attributeResult; 85 } 86 87 /** 88 * Gets the length of the represented node. This is always 1. 89 * 90 * @return the length 91 */ 92 @Override 93 public int getLength() { 94 return 1; 95 } 96 97 /** 98 * Gets the name of this node. This is the attribute name. 99 * 100 * @return the name of this node 101 */ 102 @Override 103 public QName getName() { 104 return new QName(null, attributeResult.getAttributeName()); 105 } 106 107 /** 108 * Returns a reference to the current node handler. The handler is obtained from the parent pointer. 109 * 110 * @return the node handler 111 */ 112 private NodeHandler<T> getNodeHandler() { 113 return getParentPointer().getNodeHandler(); 114 } 115 116 /** 117 * Gets a reference to the parent node pointer. 118 * 119 * @return the parent pointer 120 */ 121 public ConfigurationNodePointer<T> getParentPointer() { 122 // safe to cast because the constructor only expects pointers of this 123 // type 124 @SuppressWarnings("unchecked") 125 final ConfigurationNodePointer<T> configurationNodePointer = (ConfigurationNodePointer<T>) getParent(); 126 return configurationNodePointer; 127 } 128 129 /** 130 * Returns the value of this node. 131 * 132 * @return this node's value 133 */ 134 @Override 135 public Object getValue() { 136 return attributeResult.getAttributeValue(getNodeHandler()); 137 } 138 139 /** 140 * Returns a flag whether this node is an attribute. Of course, this is the case. 141 * 142 * @return the attribute flag 143 */ 144 @Override 145 public boolean isAttribute() { 146 return true; 147 } 148 149 /** 150 * Returns a flag whether the represented node is a collection. This is not the case. 151 * 152 * @return the collection flag 153 */ 154 @Override 155 public boolean isCollection() { 156 return false; 157 } 158 159 /** 160 * Returns a flag whether the represented node is a leaf. This is the case for attributes. 161 * 162 * @return the leaf flag 163 */ 164 @Override 165 public boolean isLeaf() { 166 return true; 167 } 168 169 /** 170 * Sets the value of this node. This is not supported because the classes of the {@code XPathExpressionEngine} are only 171 * used for queries. This implementation always throws an exception. 172 * 173 * @param value the new value 174 */ 175 @Override 176 public void setValue(final Object value) { 177 throw new UnsupportedOperationException("Updating the value is not supported!"); 178 } 179 180 /** 181 * Tests if this node matches the given test. Attribute nodes are text nodes, too, because they can contain a value. 182 * 183 * @param test the test object 184 * @return a flag if this node corresponds to the test 185 */ 186 @Override 187 public boolean testNode(final NodeTest test) { 188 if (test instanceof NodeTypeTest && ((NodeTypeTest) test).getNodeType() == Compiler.NODE_TYPE_TEXT) { 189 return true; 190 } 191 return super.testNode(test); 192 } 193 }