- /*
- * 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.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: 1.22 $ $Date: 2004/02/29 14:17:37 $
- */
- public class PredicateContext extends EvalContext {
- private Expression expression;
- private boolean done = false;
- private Expression nameTestExpression;
- private PropertyPointer dynamicPropertyPointer;
-
- 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);
- }
- else if (InfoSetUtil.booleanValue(pred)) {
- position++;
- return true;
- }
- }
- }
- return false;
- }
-
- /**
- * Used for an optimized access to dynamic properties using the
- * "map[@name = 'name']" syntax
- */
- 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) {
- if (!setupDynamicPropertyPointer()) {
- return setPositionStandard(position);
- }
- }
- if (position < 1
- || position > dynamicPropertyPointer.getLength()) {
- return false;
- }
- dynamicPropertyPointer.setIndex(position - 1);
- return true;
- }
- }
-
- public NodePointer getCurrentNodePointer() {
- if (position == 0) {
- if (!setPosition(1)) {
- return null;
- }
- }
- if (dynamicPropertyPointer != null) {
- return dynamicPropertyPointer.getValuePointer();
- }
- else {
- return parentContext.getCurrentNodePointer();
- }
- }
-
- public void reset() {
- super.reset();
- done = false;
- }
-
- public boolean nextSet() {
- reset();
- return parentContext.nextSet();
- }
-
- private boolean setPositionStandard(int position) {
- if (this.position > position) {
- reset();
- }
-
- while (this.position < position) {
- if (!nextNode()) {
- return false;
- }
- }
- return true;
- }
- }