src/org/apache/xalan/xsltc/compiler/util/ObjectType.java

/*
 * @(#)$Id$
 *
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 2001, Sun
 * Microsystems., http://www.sun.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * @author Todd Miller
 * @author Santiago Pericas-Geertsen
 *
 */

package org.apache.xalan.xsltc.compiler.util;

import org.apache.bcel.generic.ALOAD;
import org.apache.bcel.generic.ASTORE;
import org.apache.bcel.generic.BranchHandle;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.GOTO;
import org.apache.bcel.generic.IFNULL;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.Constants;
import org.apache.xml.utils.ObjectFactory;

public final class ObjectType extends Type {
    
    private String _javaClassName = "java.lang.Object";
    private Class  _clazz = java.lang.Object.class;

    /**
     * Used to represent a Java Class type such is required to support 
     * non-static java functions. 
     * @param javaClassName name of the class such as 'com.foo.Processor'
     */
    protected ObjectType(String javaClassName) {
	_javaClassName = javaClassName;

	try {
          _clazz = ObjectFactory.findProviderClass(
            javaClassName, ObjectFactory.findClassLoader(), true);
	}
	catch (ClassNotFoundException e) {
	  _clazz = null;
	}
    }
    
    protected ObjectType(Class clazz) {
        _clazz = clazz;
        _javaClassName = clazz.getName();	
    }

    public int hashCode() {
        return toString().hashCode();
    }

    public boolean equals(Object obj) {
        return (obj instanceof ObjectType);
    }

    public String getJavaClassName() {
	return _javaClassName;
    }
    
    public Class getJavaClass() {
        return _clazz;	
    }

    public String toString() {
	return _javaClassName;
    }

    public boolean identicalTo(Type other) {
	return this == other;
    }

    public String toSignature() {
	final StringBuffer result = new StringBuffer("L");
	result.append(_javaClassName.replace('.', '/')).append(';');
	return result.toString();
    }

    public org.apache.bcel.generic.Type toJCType() {
	return Util.getJCRefType(toSignature());
    }

    /**
     * Translates a void into an object of internal type <code>type</code>.
     * This translation is needed when calling external functions
     * that return void.
     *
     * @see	org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    Type type) {
	if (type == Type.String) {
	    translateTo(classGen, methodGen, (StringType) type);
	}
	else {
	    ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
					toString(), type.toString());
	    classGen.getParser().reportError(Constants.FATAL, err);
	}
    }

    /**
     * Expects an integer on the stack and pushes its string value by calling
     * <code>Integer.toString(int i)</code>.
     *
     * @see	org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    StringType type) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	il.append(DUP);
	final BranchHandle ifNull = il.append(new IFNULL(null));
	il.append(new INVOKEVIRTUAL(cpg.addMethodref(_javaClassName,
						    "toString",
						    "()" + STRING_SIG)));
	final BranchHandle gotobh = il.append(new GOTO(null));
	ifNull.setTarget(il.append(POP));
	il.append(new PUSH(cpg, ""));
	gotobh.setTarget(il.append(NOP));
    }

    /**
     * Translates an object of this type to the external (Java) type denoted
     * by <code>clazz</code>. This method is used to translate parameters 
     * when external functions are called.
     */ 
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    Class clazz) {
        if (clazz.isAssignableFrom(_clazz))
	    methodGen.getInstructionList().append(NOP);
	else {
	    ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
			       toString(), clazz.getClass().toString());
	    classGen.getParser().reportError(Constants.FATAL, err);	  	
	}
    }
	
    /**
     * Translates an external Java type into an Object type 
     */
    public void translateFrom(ClassGenerator classGen, 
			      MethodGenerator methodGen, Class clazz) {
	methodGen.getInstructionList().append(NOP);
    }

    public Instruction LOAD(int slot) {
	return new ALOAD(slot);
    }
	
    public Instruction STORE(int slot) {
	return new ASTORE(slot);
    }
}