bytearrayclasspath.java

Javassist是一个开源的分析、编辑和创建Java字节码的类库。是由东京技术学院的数学和计算机科学系的 Shigeru Chiba 所创建的。它已加入了开放源代码JBoss 应用服务器项目,通过使

/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999-2006 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;

import java.io.*;
import java.net.URL;
import java.net.MalformedURLException;

/**
 * A <code>ByteArrayClassPath</code> contains bytes that is served as
 * a class file to a <code>ClassPool</code>.  It is useful to convert
 * a byte array to a <code>CtClass</code> object.
 *
 * <p>For example, if you want to convert a byte array <code>b</code>
 * into a <code>CtClass</code> object representing the class with a name
 * <code>classname</code>, then do as following:
 *
 * <ul><pre>
 * ClassPool cp = ClassPool.getDefault();
 * cp.insertClassPath(new ByteArrayClassPath(classname, b));
 * CtClass cc = cp.get(classname);
 * </pre></ul>
 *
 * <p>The <code>ClassPool</code> object <code>cp</code> uses the created
 * <code>ByteArrayClassPath</code> object as the source of the class file.
 * 
 * <p>A <code>ByteArrayClassPath</code> must be instantiated for every
 * class.  It contains only a single class file.
 *
 * @see javassist.ClassPath
 * @see ClassPool#insertClassPath(ClassPath)
 * @see ClassPool#appendClassPath(ClassPath)
 * @see ClassPool#makeClass(InputStream)
 */
public class ByteArrayClassPath implements ClassPath {
    protected String classname;
    protected byte[] classfile;

    /*
     * Creates a <code>ByteArrayClassPath</code> containing the given
     * bytes.
     *
     * @param name              a fully qualified class name
     * @param classfile         the contents of a class file.
     */
    public ByteArrayClassPath(String name, byte[] classfile) {
        this.classname = name;
        this.classfile = classfile;
    }

    /**
     * Closes this class path.
     */
    public void close() {}

    public String toString() {
        return "byte[]:" + classname;
    }

    /**
     * Opens the class file.
     */
    public InputStream openClassfile(String classname) {
        if(this.classname.equals(classname))
            return new ByteArrayInputStream(classfile);
        else
            return null;
    }

    /**
     * Obtains the URL.
     */
    public URL find(String classname) {
        if(this.classname.equals(classname)) {
            String cname = classname.replace('.', '/') + ".class";
            try {
                // return new File(cname).toURL();
                return new URL("file:/ByteArrayClassPath/" + cname);
            }
            catch (MalformedURLException e) {}
        }

        return null;
    }
}