| /* |
| * 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. |
| */ |
| /* |
| * $Id$ |
| */ |
| |
| package org.apache.xalan.xsltc.compiler; |
| |
| import java.util.Vector; |
| |
| import org.apache.bcel.generic.ConstantPoolGen; |
| import org.apache.bcel.generic.INVOKEINTERFACE; |
| import org.apache.bcel.generic.INVOKESPECIAL; |
| import org.apache.bcel.generic.INVOKEVIRTUAL; |
| import org.apache.bcel.generic.InstructionList; |
| import org.apache.bcel.generic.NEW; |
| import org.apache.xalan.xsltc.compiler.util.ClassGenerator; |
| import org.apache.xalan.xsltc.compiler.util.MethodGenerator; |
| import org.apache.xalan.xsltc.compiler.util.Type; |
| import org.apache.xalan.xsltc.compiler.util.TypeCheckError; |
| import org.apache.xml.dtm.Axis; |
| import org.apache.xml.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)); |
| |
| } |
| } |
| } |