code: /*
   * 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.INVOKESPECIAL;
  import org.apache.bcel.generic.INVOKEVIRTUAL;
  import org.apache.bcel.generic.Instruction;
  import org.apache.bcel.generic.InstructionList;
  import org.apache.bcel.generic.NEW;
  import org.apache.bcel.generic.PUSH;
  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;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   */
  final class ConcatCall extends FunctionCall {
      public ConcatCall(QName fname, Vector arguments) {
  	super(fname, arguments);
      }
  
      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
  	for (int i = 0; i < argumentCount(); i++) {
  	    final Expression exp = argument(i);
  	    if (!exp.typeCheck(stable).identicalTo(Type.String)) {
  		setArgument(i, new CastExpr(exp, Type.String));
  	    }
  	}
  	return _type = Type.String;
      }
  	
      /** translate leaves a String on the stack */
      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  	final int nArgs = argumentCount();
  	
  	switch (nArgs) {
  	case 0:
  	    il.append(new PUSH(cpg, EMPTYSTRING));
  	    break;
  	    
  	case 1:
  	    argument().translate(classGen, methodGen);
  	    break;
  
  	default:
  	    final int initBuffer = cpg.addMethodref(STRING_BUFFER_CLASS,
  						    "<init>", "()V");
  	    final Instruction append =
  		new INVOKEVIRTUAL(cpg.addMethodref(STRING_BUFFER_CLASS,
  						   "append",
  						   "("+STRING_SIG+")"
  						   +STRING_BUFFER_SIG));
  	    
  	    final int toString = cpg.addMethodref(STRING_BUFFER_CLASS,
  						  "toString",
  						  "()"+STRING_SIG);
  	    
  	    il.append(new NEW(cpg.addClass(STRING_BUFFER_CLASS)));
  	    il.append(DUP);
  	    il.append(new INVOKESPECIAL(initBuffer));
  	    for (int i = 0; i < nArgs; i++) {
  		argument(i).translate(classGen, methodGen);
  		il.append(append);
  	    }
  	    il.append(new INVOKEVIRTUAL(toString));
  	}
      }
  }
  