/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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. */ package org.apache.commons.jxpath.ri.model.beans; import org.apache.commons.jxpath.JXPathContext; import org.apache.commons.jxpath.ri.QName; import org.apache.commons.jxpath.ri.model.NodePointer; /** * Used when there is a need to construct a Pointer for a collection element * that does not exist. For example, if the path is "foo[3]", but the * collection "foo" only has one element or is empty or is null, the * NullElementPointer can be used to capture this situation without putting a * regular NodePointer into an invalid state. Just create a NullElementPointer * with index 2 (= 3 - 1) and a "foo" pointer as the parent. * * @author Dmitri Plotnikov * @version $Revision: 652884 $ $Date: 2008-05-02 15:02:00 -0500 (Fri, 02 May 2008) $ */ public class NullElementPointer extends CollectionPointer { private static final long serialVersionUID = 8714236818791036721L; /** * Create a new NullElementPointer. * @param parent parent pointer * @param index int */ public NullElementPointer(NodePointer parent, int index) { super(parent, (Object) null); this.index = index; } public QName getName() { return null; } public Object getBaseValue() { return null; } public Object getImmediateNode() { return null; } public boolean isLeaf() { return true; } public boolean isCollection() { return false; } /** * Get the property pointer for this. * @return PropertyPointer */ public PropertyPointer getPropertyPointer() { return new NullPropertyPointer(this); } public NodePointer getValuePointer() { return new NullPointer(this, getName()); } public void setValue(Object value) { throw new UnsupportedOperationException( "Collection element does not exist: " + this); } public boolean isActual() { return false; } public boolean isContainer() { return true; } public NodePointer createPath(JXPathContext context) { return parent.createChild(context, null, index); } public NodePointer createPath(JXPathContext context, Object value) { return parent.createChild(context, null, index, value); } public int hashCode() { return getImmediateParentPointer().hashCode() + index; } public boolean equals(Object object) { if (object == this) { return true; } if (!(object instanceof NullElementPointer)) { return false; } NullElementPointer other = (NullElementPointer) object; return getImmediateParentPointer() == other.getImmediateParentPointer() && index == other.index; } public int getLength() { return 0; } public String asPath() { StringBuffer buffer = new StringBuffer(); NodePointer parent = getImmediateParentPointer(); if (parent != null) { buffer.append(parent.asPath()); } if (index != WHOLE_COLLECTION) { // Address the list[1][2] case if (parent != null && parent.getIndex() != WHOLE_COLLECTION) { buffer.append("/."); } else if (parent != null && parent.getImmediateParentPointer() != null && parent.getImmediateParentPointer().getIndex() != WHOLE_COLLECTION) { buffer.append("/."); } buffer.append("[").append(index + 1).append(']'); } return buffer.toString(); } }