001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements. See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership. The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the  "License");
007     * you may not use this file except in compliance with the License.
008     * You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    /*
019     * $Id: BooleanExpr.java 468650 2006-10-28 07:03:30Z minchau $
020     */
021    
022    package org.apache.xalan.xsltc.compiler;
023    
024    import org.apache.bcel.generic.ConstantPoolGen;
025    import org.apache.bcel.generic.GOTO;
026    import org.apache.bcel.generic.InstructionList;
027    import org.apache.bcel.generic.PUSH;
028    import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
029    import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
030    import org.apache.xalan.xsltc.compiler.util.Type;
031    import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
032    
033    /**
034     * This class implements inlined calls to the XSLT standard functions 
035     * true() and false().
036     * @author Jacek Ambroziak
037     * @author Santiago Pericas-Geertsen
038     */
039    final class BooleanExpr extends Expression {
040        private boolean _value;
041    
042        public BooleanExpr(boolean value) {
043            _value = value;
044        }
045    
046        public Type typeCheck(SymbolTable stable) throws TypeCheckError {
047            _type = Type.Boolean;
048            return _type;
049        }
050    
051        public String toString() {
052            return _value ? "true()" : "false()";
053        }
054    
055        public boolean getValue() {
056            return _value;
057        }
058    
059        public boolean contextDependent() {
060            return false;
061        }
062    
063        public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
064            ConstantPoolGen cpg = classGen.getConstantPool();
065            InstructionList il = methodGen.getInstructionList();
066            il.append(new PUSH(cpg, _value));
067        }
068    
069        public void translateDesynthesized(ClassGenerator classGen,
070                                           MethodGenerator methodGen) {
071            final InstructionList il = methodGen.getInstructionList();
072            if (_value) {
073                il.append(NOP);     // true list falls through
074            }
075            else {
076                _falseList.add(il.append(new GOTO(null)));
077            }
078        }
079    }