- /*
- * 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: FilterExpr.java,v 1.11 2004/02/16 22:24:29 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.INVOKESTATIC;
- 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.NodeSetType;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
-
- /**
- * @author Jacek Ambroziak
- * @author Santiago Pericas-Geertsen
- * @author Morten Jorgensen
- */
- class FilterExpr extends Expression {
-
- /**
- * Primary expression of this filter. I.e., 'e' in '(e)[p1]...[pn]'.
- */
- private Expression _primary;
-
- /**
- * Array of predicates in '(e)[p1]...[pn]'.
- */
- private final Vector _predicates;
-
- public FilterExpr(Expression primary, Vector predicates) {
- _primary = primary;
- _predicates = predicates;
- primary.setParent(this);
- }
-
- protected Expression getExpr() {
- if (_primary instanceof CastExpr)
- return ((CastExpr)_primary).getExpr();
- else
- return _primary;
- }
-
- public void setParser(Parser parser) {
- super.setParser(parser);
- _primary.setParser(parser);
- if (_predicates != null) {
- final int n = _predicates.size();
- for (int i = 0; i < n; i++) {
- final Expression exp = (Expression)_predicates.elementAt(i);
- exp.setParser(parser);
- exp.setParent(this);
- }
- }
- }
-
- public String toString() {
- return "filter-expr(" + _primary + ", " + _predicates + ")";
- }
-
- /**
- * Type check a FilterParentPath. If the filter is not a node-set add a
- * cast to node-set only if it is of reference type. This type coercion
- * is needed for expressions like $x where $x is a parameter reference.
- * All optimizations are turned off before type checking underlying
- * predicates.
- */
- public Type typeCheck(SymbolTable stable) throws TypeCheckError {
- Type ptype = _primary.typeCheck(stable);
-
- if (ptype instanceof NodeSetType == false) {
- if (ptype instanceof ReferenceType) {
- _primary = new CastExpr(_primary, Type.NodeSet);
- }
- else {
- throw new TypeCheckError(this);
- }
- }
-
- // Type check predicates and turn all optimizations off
- int n = _predicates.size();
- for (int i = 0; i < n; i++) {
- Predicate pred = (Predicate) _predicates.elementAt(i);
- pred.dontOptimize();
- pred.typeCheck(stable);
- }
- return _type = Type.NodeSet;
- }
-
- /**
- * Translate a filter expression by pushing the appropriate iterator
- * onto the stack.
- */
- public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
- if (_predicates.size() > 0) {
- translatePredicates(classGen, methodGen);
- }
- else {
- _primary.translate(classGen, methodGen);
- }
- }
-
- /**
- * Translate a sequence of predicates. Each predicate is translated
- * by constructing an instance of <code>CurrentNodeListIterator</code>
- * which is initialized from another iterator (recursive call), a
- * filter and a closure (call to translate on the predicate) and "this".
- */
- public void translatePredicates(ClassGenerator classGen,
- MethodGenerator methodGen) {
- final ConstantPoolGen cpg = classGen.getConstantPool();
- final InstructionList il = methodGen.getInstructionList();
-
- // If not predicates left, translate primary expression
- if (_predicates.size() == 0) {
- translate(classGen, methodGen);
- }
- else {
- // Translate predicates from right to left
- final int initCNLI = cpg.addMethodref(CURRENT_NODE_LIST_ITERATOR,
- "<init>",
- "("+NODE_ITERATOR_SIG+"Z"+
- CURRENT_NODE_LIST_FILTER_SIG +
- NODE_SIG+TRANSLET_SIG+")V");
-
- Predicate predicate = (Predicate)_predicates.lastElement();
- _predicates.remove(predicate);
-
- // Create a CurrentNodeListIterator
- il.append(new NEW(cpg.addClass(CURRENT_NODE_LIST_ITERATOR)));
- il.append(DUP);
-
- // Translate the rest of the predicates from right to left
- translatePredicates(classGen, methodGen);
-
- // Initialize CurrentNodeListIterator
- il.append(ICONST_1);
- predicate.translate(classGen, methodGen);
- il.append(methodGen.loadCurrentNode());
- il.append(classGen.loadTranslet());
- il.append(new INVOKESPECIAL(initCNLI));
- }
- }
- }