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: ConcatCall.java 468650 2006-10-28 07:03:30Z minchau $
020     */
021    
022    package org.apache.xalan.xsltc.compiler;
023    
024    import java.util.Vector;
025    
026    import org.apache.bcel.generic.ConstantPoolGen;
027    import org.apache.bcel.generic.INVOKESPECIAL;
028    import org.apache.bcel.generic.INVOKEVIRTUAL;
029    import org.apache.bcel.generic.Instruction;
030    import org.apache.bcel.generic.InstructionList;
031    import org.apache.bcel.generic.NEW;
032    import org.apache.bcel.generic.PUSH;
033    import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
034    import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
035    import org.apache.xalan.xsltc.compiler.util.Type;
036    import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
037    
038    /**
039     * @author Jacek Ambroziak
040     * @author Santiago Pericas-Geertsen
041     */
042    final class ConcatCall extends FunctionCall {
043        public ConcatCall(QName fname, Vector arguments) {
044            super(fname, arguments);
045        }
046    
047        public Type typeCheck(SymbolTable stable) throws TypeCheckError {
048            for (int i = 0; i < argumentCount(); i++) {
049                final Expression exp = argument(i);
050                if (!exp.typeCheck(stable).identicalTo(Type.String)) {
051                    setArgument(i, new CastExpr(exp, Type.String));
052                }
053            }
054            return _type = Type.String;
055        }
056            
057        /** translate leaves a String on the stack */
058        public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
059            final ConstantPoolGen cpg = classGen.getConstantPool();
060            final InstructionList il = methodGen.getInstructionList();
061            final int nArgs = argumentCount();
062            
063            switch (nArgs) {
064            case 0:
065                il.append(new PUSH(cpg, EMPTYSTRING));
066                break;
067                
068            case 1:
069                argument().translate(classGen, methodGen);
070                break;
071    
072            default:
073                final int initBuffer = cpg.addMethodref(STRING_BUFFER_CLASS,
074                                                        "<init>", "()V");
075                final Instruction append =
076                    new INVOKEVIRTUAL(cpg.addMethodref(STRING_BUFFER_CLASS,
077                                                       "append",
078                                                       "("+STRING_SIG+")"
079                                                       +STRING_BUFFER_SIG));
080                
081                final int toString = cpg.addMethodref(STRING_BUFFER_CLASS,
082                                                      "toString",
083                                                      "()"+STRING_SIG);
084                
085                il.append(new NEW(cpg.addClass(STRING_BUFFER_CLASS)));
086                il.append(DUP);
087                il.append(new INVOKESPECIAL(initBuffer));
088                for (int i = 0; i < nArgs; i++) {
089                    argument(i).translate(classGen, methodGen);
090                    il.append(append);
091                }
092                il.append(new INVOKEVIRTUAL(toString));
093            }
094        }
095    }