/*
* 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();
}
}
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