langcall.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: LangCall.java,v 1.2.4.1 2005/09/01 15:54:25 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.ILOAD;
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.FilterGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.StringType;
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
 */
final class LangCall extends FunctionCall {
    private Expression _lang;
    private Type _langType;

    /**
     * Get the parameters passed to function:
     *   lang(string)
     */
    public LangCall(QName fname, Vector arguments) {
	super(fname, arguments);
	_lang = argument(0);
    }

    /**
     *
     */
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	_langType = _lang.typeCheck(stable);
	if (!(_langType instanceof StringType)) {
	    _lang = new CastExpr(_lang, Type.String);
	}
	return Type.Boolean;
    }

    /**
     *
     */
    public Type getType() {
	return(Type.Boolean);
    }

    /**
     * This method is called when the constructor is compiled in
     * Stylesheet.compileConstructor() and not as the syntax tree is traversed.
     */
    public void translate(ClassGenerator classGen,
			  MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	final int tst = cpg.addMethodref(BASIS_LIBRARY_CLASS,
					 "testLanguage",
					 "("+STRING_SIG+DOM_INTF_SIG+"I)Z");
	_lang.translate(classGen,methodGen);
	il.append(methodGen.loadDOM());
	if (classGen instanceof FilterGenerator)
	    il.append(new ILOAD(1));
	else
	    il.append(methodGen.loadContextNode());
	il.append(new INVOKESTATIC(tst));
    }
}