- /*
- * Copyright 2001-2004 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.
- */
- /*
- * $Id: UnionPathExpr.java,v 1.10 2004/02/16 22:25:10 minchau Exp $
- */
-
- package com.sun.org.apache.xalan.internal.xsltc.compiler;
-
- import java.util.Vector;
-
- import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
- import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
- import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
- import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
- import com.sun.org.apache.bcel.internal.generic.InstructionList;
- import com.sun.org.apache.bcel.internal.generic.NEW;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
- import com.sun.org.apache.xalan.internal.xsltc.dom.Axis;
- import com.sun.org.apache.xml.internal.dtm.DTM;
-
- /**
- * @author Jacek Ambroziak
- * @author Santiago Pericas-Geertsen
- */
- final class UnionPathExpr extends Expression {
-
- private final Expression _pathExpr;
- private final Expression _rest;
- private boolean _reverse = false;
-
- // linearization for top level UnionPathExprs
- private Expression[] _components;
-
- public UnionPathExpr(Expression pathExpr, Expression rest) {
- _pathExpr = pathExpr;
- _rest = rest;
- }
-
- public void setParser(Parser parser) {
- super.setParser(parser);
- // find all expressions in this Union
- final Vector components = new Vector();
- flatten(components);
- final int size = components.size();
- _components = (Expression[])components.toArray(new Expression[size]);
- for (int i = 0; i < size; i++) {
- _components[i].setParser(parser);
- _components[i].setParent(this);
- if (_components[i] instanceof Step) {
- final Step step = (Step)_components[i];
- final int axis = step.getAxis();
- final int type = step.getNodeType();
- // Put attribute iterators first
- if ((axis == Axis.ATTRIBUTE) || (type == DTM.ATTRIBUTE_NODE)) {
- _components[i] = _components[0];
- _components[0] = step;
- }
- // Check if the union contains a reverse iterator
- if (Axis.isReverse[axis]) _reverse = true;
- }
- }
- // No need to reverse anything if another expression lies on top of this
- if (getParent() instanceof Expression) _reverse = false;
- }
-
- public Type typeCheck(SymbolTable stable) throws TypeCheckError {
- final int length = _components.length;
- for (int i = 0; i < length; i++) {
- if (_components[i].typeCheck(stable) != Type.NodeSet) {
- _components[i] = new CastExpr(_components[i], Type.NodeSet);
- }
- }
- return _type = Type.NodeSet;
- }
-
- public String toString() {
- return "union(" + _pathExpr + ", " + _rest + ')';
- }
-
- private void flatten(Vector components) {
- components.addElement(_pathExpr);
- if (_rest != null) {
- if (_rest instanceof UnionPathExpr) {
- ((UnionPathExpr)_rest).flatten(components);
- }
- else {
- components.addElement(_rest);
- }
- }
- }
-
- public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
- final ConstantPoolGen cpg = classGen.getConstantPool();
- final InstructionList il = methodGen.getInstructionList();
-
- final int init = cpg.addMethodref(UNION_ITERATOR_CLASS,
- "<init>",
- "("+DOM_INTF_SIG+")V");
- final int iter = cpg.addMethodref(UNION_ITERATOR_CLASS,
- ADD_ITERATOR,
- ADD_ITERATOR_SIG);
-
- // Create the UnionIterator and leave it on the stack
- il.append(new NEW(cpg.addClass(UNION_ITERATOR_CLASS)));
- il.append(DUP);
- il.append(methodGen.loadDOM());
- il.append(new INVOKESPECIAL(init));
-
- // Add the various iterators to the UnionIterator
- final int length = _components.length;
- for (int i = 0; i < length; i++) {
- _components[i].translate(classGen, methodGen);
- il.append(new INVOKEVIRTUAL(iter));
- }
-
- // Order the iterator only if strictly needed
- if (_reverse) {
- final int order = cpg.addInterfaceMethodref(DOM_INTF,
- ORDER_ITERATOR,
- ORDER_ITERATOR_SIG);
- il.append(methodGen.loadDOM());
- il.append(SWAP);
- il.append(methodGen.loadContextNode());
- il.append(new INVOKEINTERFACE(order, 3));
-
- }
- }
- }