classpath.java

该开源工具主要用于class文件的操作

package org.apache.bcel.util;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import java.util.*;
import java.util.zip.*;
import java.io.*;

/**
 * Responsible for loading (class) files from the CLASSPATH. Inspired by
 * sun.tools.ClassPath.
 *
 * @version $Id: ClassPath.java,v 1.3 2001/12/14 18:44:29 mdahm Exp $
 * @author  <A HREF="mailto:[e-mail]">M. Dahm</A>
 */
public class ClassPath {
  private PathEntry[] paths;

  /**
   * Search for classes in given path.
   */
  public ClassPath(String class_path) {
    ArrayList vec = new ArrayList();

    for(StringTokenizer tok=new StringTokenizer(class_path,
						System.getProperty("path.separator"));
	tok.hasMoreTokens();)
    {
      String path = tok.nextToken();
      
      if(!path.equals("")) {
	File file = new File(path);

	try {
	  if(file.exists()) {
	    if(file.isDirectory())
	      vec.add(new Dir(path));
	    else
	      vec.add(new Zip(new ZipFile(file)));
	  }
	} catch(IOException e) {
	  System.err.println("CLASSPATH component " + file + ": " + e);
	}
      }
    }

    paths = new PathEntry[vec.size()];
    vec.toArray(paths);
  }

  /**
   * Search for classes in CLASSPATH.
   */
  public ClassPath() {
    this(getClassPath());
  }

  private static final void getPathComponents(String path, ArrayList list) {
    if(path != null) {
      StringTokenizer tok = new StringTokenizer(path, File.pathSeparator);

      while(tok.hasMoreTokens()) {
        String name = tok.nextToken();
        File   file = new File(name);

	if(file.exists())
	  list.add(name);
      }
    }
  }

  /** Checks for class path components in the following properties:
   * "java.class.path", "sun.boot.class.path", "java.ext.dirs"
   *
   * @return class path as used by default by BCEL
   */
  public static final String getClassPath() {
    String class_path = System.getProperty("java.class.path");
    String boot_path  = System.getProperty("sun.boot.class.path");
    String ext_path   = System.getProperty("java.ext.dirs");

    ArrayList list = new ArrayList();

    getPathComponents(class_path, list);
    getPathComponents(boot_path, list);

    ArrayList dirs = new ArrayList();
    getPathComponents(ext_path, dirs);

    for(Iterator e = dirs.iterator(); e.hasNext(); ) {
      File     ext_dir    = new File((String)e.next());
      String[] extensions = ext_dir.list(new FilenameFilter() {
	public boolean accept(File dir, String name) {
	  name = name.toLowerCase();
	  return name.endsWith(".zip") || name.endsWith(".jar");
	}
      });

      if(extensions != null)
	for(int i=0; i < extensions.length; i++)
	  list.add(ext_path + File.separatorChar + extensions[i]);
    }

    StringBuffer buf = new StringBuffer();

    for(Iterator e = list.iterator(); e.hasNext(); ) {
      buf.append((String)e.next());

      if(e.hasNext())
	buf.append(File.pathSeparatorChar);
    }

    return buf.toString();
  }

  /**
   * @param name fully qualified class name, e.g. java.lang.String
   * @return input stream for class
   */
  public InputStream getInputStream(String name) throws IOException {
    return getInputStream(name, ".class");
  }
    
  /**
   * Return stream for class or resource on CLASSPATH.
   *
   * @param name fully qualified file name, e.g. java/lang/String
   * @param suffix file name ends with suff, e.g. .java
   * @return input stream for file on class path
   */
  public InputStream getInputStream(String name, String suffix) throws IOException {
    InputStream is = null;

    try {
      is = getClass().getClassLoader().getResourceAsStream(name + suffix);
    } catch(Exception e) { }

    if(is != null)
      return is;
    
    return getClassFile(name, suffix).getInputStream();
  }

  /**
   * @param name fully qualified file name, e.g. java/lang/String
   * @param suffix file name ends with suff, e.g. .java
   * @return class file for the java class
   */
  public ClassFile getClassFile(String name, String suffix) throws IOException {
    for(int i=0; i < paths.length; i++) {
      ClassFile cf;

      if((cf = paths[i].getClassFile(name, suffix)) != null)
	return cf;
    }

    throw new IOException("Couldn't find: " + name + suffix);
  }

  /**
   * @param name fully qualified class name, e.g. java.lang.String
   * @return input stream for class
   */
  public ClassFile getClassFile(String name) throws IOException {
    return getClassFile(name, ".class");
  }

  /**
   * @param name fully qualified file name, e.g. java/lang/String
   * @param suffix file name ends with suffix, e.g. .java
   * @return byte array for file on class path
   */
  public byte[] getBytes(String name, String suffix) throws IOException {
    InputStream is = getInputStream(name, suffix);
    
    if(is == null)
      throw new IOException("Couldn't find: " + name + suffix);

    DataInputStream dis   = new DataInputStream(is);
    byte[]          bytes = new byte[is.available()];
    dis.readFully(bytes);
    dis.close(); is.close();

    return bytes;
  }

  /**
   * @return byte array for class
   */
  public byte[] getBytes(String name) throws IOException {
    return getBytes(name, ".class");
  }

  /**
   * @param name name of file to search for, e.g. java/lang/String.java
   * @return full (canonical) path for file
   */
  public String getPath(String name) throws IOException {
    int    index  = name.lastIndexOf('.');
    String suffix = "";

    if(index > 0) {
      suffix = name.substring(index);
      name   = name.substring(0, index);
    }
    
    return getPath(name, suffix);
  }

  /**
   * @param name name of file to search for, e.g. java/lang/String
   * @param suffix file name suffix, e.g. .java
   * @return full (canonical) path for file, if it exists
   */
  public String getPath(String name, String suffix) throws IOException {
    return getClassFile(name, suffix).getPath();
  }

  private static abstract class PathEntry {
    abstract ClassFile getClassFile(String name, String suffix) throws IOException;
  }

  /** Contains information about file/ZIP entry of the Java class.
   */
  public abstract static class ClassFile {
    /** @return input stream for class file.
     */
    public abstract InputStream getInputStream() throws IOException;

    /** @return canonical path to class file.
     */
    public abstract String getPath();

    /** @return modification time of class file.
     */
    public abstract long getTime();

    /** @return size of class file.
     */
    public abstract long getSize();
  }
    
  private static class Dir extends PathEntry {
    private String dir;

    Dir(String d) { dir = d; }

    ClassFile getClassFile(String name, String suffix) throws IOException {
      final File file = new File(dir + File.separatorChar +
				 name.replace('.', File.separatorChar) + suffix);
      
      return file.exists()? new ClassFile() {
	public InputStream getInputStream() throws IOException { return new FileInputStream(file); }

	public String      getPath()        { try {
	  return file.getCanonicalPath(); 
	} catch(IOException e) { return null; }

	}
	public long        getTime()        { return file.lastModified(); }
	public long        getSize()        { return file.length(); }
      } : null;
    }

    public String toString() { return dir; }
  }

  private static class Zip extends PathEntry {
    private ZipFile zip;

    Zip(ZipFile z) { zip = z; }

    ClassFile getClassFile(String name, String suffix) throws IOException {
      final ZipEntry entry = zip.getEntry(name.replace('.', '/') + suffix);

      return (entry != null)? new ClassFile() {
	public InputStream getInputStream() throws IOException { return zip.getInputStream(entry); }
	public String      getPath()        { return entry.toString(); }
	public long        getTime()        { return entry.getTime(); }
	public long        getSize()       { return entry.getSize(); }
      } : null;
    }
  }
}