namebase.java

java1.6众多例子参考

/*
 * 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: NameBase.java,v 1.2.4.1 2005/09/02 10:17:31 pvedula 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.INVOKESTATIC;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
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.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;

/**
 * @author Morten Jorgensen
 * @author Erwin Bolwidt <[e-mail]>
 */
class NameBase extends FunctionCall {

    private Expression _param = null;
    private Type       _paramType = Type.Node;

    /**
     * Handles calls with no parameter (current node is implicit parameter).
     */
    public NameBase(QName fname) {
	super(fname);
    }

    /**
     * Handles calls with one parameter (either node or node-set).
     */
    public NameBase(QName fname, Vector arguments) {
	super(fname, arguments);
	_param = argument(0);
    }


    /**
     * Check that we either have no parameters or one parameter that is
     * either a node or a node-set.
     */
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {

	// Check the argument type (if any)
	switch(argumentCount()) {
	case 0:
	    _paramType = Type.Node;
	    break;
	case 1:
	    _paramType = _param.typeCheck(stable);
	    break;
	default:
	    throw new TypeCheckError(this);
	}

	// The argument has to be a node, a node-set or a node reference
	if ((_paramType != Type.NodeSet) &&
	    (_paramType != Type.Node) &&
	    (_paramType != Type.Reference)) {
	    throw new TypeCheckError(this);
	}

	return (_type = Type.String);
    }

    public Type getType() {
	return _type;
    }

    /**
     * Translate the code required for getting the node for which the
     * QName, local-name or namespace URI should be extracted.
     */
    public void translate(ClassGenerator classGen,
			  MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	il.append(methodGen.loadDOM());
	
	// Function was called with no parameters
	if (argumentCount() == 0) {
	    il.append(methodGen.loadContextNode());
	}
	// Function was called with node parameter
	else if (_paramType == Type.Node) {
	    _param.translate(classGen, methodGen);
	}
	else if (_paramType == Type.Reference) {
	    _param.translate(classGen, methodGen);
	    il.append(new INVOKESTATIC(cpg.addMethodref
				       (BASIS_LIBRARY_CLASS,
					"referenceToNodeSet",
					"("
					+ OBJECT_SIG
					+ ")"
					+ NODE_ITERATOR_SIG)));
	    il.append(methodGen.nextNode());
	}
	// Function was called with node-set parameter
	else {
	    _param.translate(classGen, methodGen);
	    _param.startIterator(classGen, methodGen);
	    il.append(methodGen.nextNode());
	}
    }
}