/*
* 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.axes;
import java.util.Iterator;
import org.apache.commons.jxpath.ri.EvalContext;
import org.apache.commons.jxpath.ri.InfoSetUtil;
import org.apache.commons.jxpath.ri.compiler.Expression;
import org.apache.commons.jxpath.ri.compiler.NameAttributeTest;
import org.apache.commons.jxpath.ri.model.NodePointer;
import org.apache.commons.jxpath.ri.model.beans.PropertyOwnerPointer;
import org.apache.commons.jxpath.ri.model.beans.PropertyPointer;
/**
* EvalContext that checks predicates.
*
* @author Dmitri Plotnikov
* @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
*/
public class PredicateContext extends EvalContext {
private Expression expression;
private boolean done = false;
private Expression nameTestExpression;
private PropertyPointer dynamicPropertyPointer;
/**
* Create a new PredicateContext.
* @param parentContext parent context
* @param expression compiled Expression
*/
public PredicateContext(EvalContext parentContext, Expression expression) {
super(parentContext);
this.expression = expression;
if (expression instanceof NameAttributeTest) {
nameTestExpression =
((NameAttributeTest) expression).getNameTestExpression();
}
}
public boolean nextNode() {
if (done) {
return false;
}
while (parentContext.nextNode()) {
if (setupDynamicPropertyPointer()) {
Object pred = nameTestExpression.computeValue(parentContext);
String propertyName = InfoSetUtil.stringValue(pred);
// At this point it would be nice to say:
// dynamicPropertyPointer.setPropertyName(propertyName)
// and then: dynamicPropertyPointer.isActual().
// However some PropertyPointers, e.g. DynamicPropertyPointer
// will declare that any property you ask for is actual.
// That's not acceptable for us: we really need to know
// if the property is currently declared. Thus,
// we'll need to perform a search.
boolean ok = false;
String[] names = dynamicPropertyPointer.getPropertyNames();
for (int i = 0; i < names.length; i++) {
if (names[i].equals(propertyName)) {
ok = true;
break;
}
}
if (ok) {
dynamicPropertyPointer.setPropertyName(propertyName);
position++;
return true;
}
}
else {
Object pred = expression.computeValue(parentContext);
if (pred instanceof Iterator) {
if (!((Iterator) pred).hasNext()) {
return false;
}
pred = ((Iterator) pred).next();
}
if (pred instanceof NodePointer) {
pred = ((NodePointer) pred).getNode();
}
if (pred instanceof Number) {
int pos = (int) InfoSetUtil.doubleValue(pred);
position++;
done = true;
return parentContext.setPosition(pos);
}
if (InfoSetUtil.booleanValue(pred)) {
position++;
return true;
}
}
}
return false;
}
/**
* Used for an optimized access to dynamic properties using the
* "map[@name = 'name']" syntax
* @return whether valid
*/
private boolean setupDynamicPropertyPointer() {
if (nameTestExpression == null) {
return false;
}
NodePointer parent = parentContext.getCurrentNodePointer();
if (parent == null) {
return false;
}
parent = parent.getValuePointer();
if (!(parent instanceof PropertyOwnerPointer)) {
return false;
}
dynamicPropertyPointer =
(PropertyPointer) ((PropertyOwnerPointer) parent)
.getPropertyPointer()
.clone();
return true;
}
public boolean setPosition(int position) {
if (nameTestExpression == null) {
return setPositionStandard(position);
}
else {
if (dynamicPropertyPointer == null && !setupDynamicPropertyPointer()) {
return setPositionStandard(position);
}
if (position < 1
|| position > dynamicPropertyPointer.getLength()) {
return false;
}
dynamicPropertyPointer.setIndex(position - 1);
return true;
}
}
public NodePointer getCurrentNodePointer() {
if (position == 0 && !setPosition(1)) {
return null;
}
if (dynamicPropertyPointer != null) {
return dynamicPropertyPointer.getValuePointer();
}
return parentContext.getCurrentNodePointer();
}
public void reset() {
super.reset();
parentContext.reset();
done = false;
}
public boolean nextSet() {
reset();
return parentContext.nextSet();
}
/**
* Basic setPosition
* @param position to set
* @return whether valid
*/
private boolean setPositionStandard(int position) {
if (this.position > position) {
reset();
}
while (this.position < position) {
if (!nextNode()) {
return false;
}
}
return true;
}
}
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