/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999-2004 Shigeru Chiba. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License.  Alternatively, the contents of this file may be used under
 * the terms of the GNU Lesser General Public License Version 2.1 or later.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 */

package javassist;

/**
 * An observer of <code>ClassPool</code>.
 * The users can define a class implementing this
 * interface and attach an instance of that class to a
 * <code>ClassPool</code> object so that it can translate a class file
 * when the class file is loaded into the JVM, for example.
 *
 * @see ClassPool#ClassPool(ClassPool,Translator)
 * @see ClassPool#getDefault(Translator)
 */
public interface Translator {
    /**
     * Is invoked by a <code>ClassPool</code> for initialization
     * when the object is attached to a <code>ClassPool</code> object.
     *
     * @param pool      the <code>ClassPool</code> that this translator
     *                          is attached to.
     *
     * @see ClassPool#ClassPool(ClassPool,Translator)
     * @see ClassPool#getDefault(Translator)
     */
    void start(ClassPool pool)
        throws NotFoundException, CannotCompileException;

    /**
     * Is invoked by a <code>ClassPool</code> for notifying that
     * a class is written out to an output stream.
     *
     * <p>If <code>CtClass.frozen()</code> is true, that is, if the class has been
     * already modified and written, then onWrite() is not invoked.
     *
     * @param pool      the <code>ClassPool</code> that this translator
     *                          is attached to.
     * @param classname         a fully-qualified class name
     *
     * @see ClassPool#writeFile(String)
     * @see ClassPool#writeFile(String, String)
     * @see ClassPool#write(String)
     * @see ClassPool#write(String,DataOutputStream)
     */
    void onWrite(ClassPool pool, String classname)
        throws NotFoundException, CannotCompileException;
}