/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * 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.

 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;

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

 */

final class Fallback extends Instruction {

    private boolean _active = false;

    /**

     * This element never produces any data on the stack

     */

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {

        if (_active) {

            return(typeCheckContents(stable));

        }

        else {

            return Type.Void;

        }

    }

    /**

     * Activate this fallback element

     */

    public void activate() {

        _active = true;

    }

    public String toString() {

        return("fallback");

    }

    /**

     * Parse contents only if this fallback element is put in place of

     * some unsupported element or non-XSLTC extension element

     */

    public void parseContents(Parser parser) {

        if (_active) parseChildren(parser);

    }

    /**

     * Translate contents only if this fallback element is put in place of

     * some unsupported element or non-XSLTC extension element

     */

    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

        final ConstantPoolGen cpg = classGen.getConstantPool();

        final InstructionList il = methodGen.getInstructionList();

        if (_active) translateContents(classGen, methodGen);

    }

}