- /*
- * Copyright 1999-2004 The Apache Software Foundation
- *
- * 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.
- */
- 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: 1.17 $ $Date: 2004/03/25 03:49:50 $
- */
- public class NullElementPointer extends CollectionPointer {
-
- 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;
- }
-
- 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();
- }
- }