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From hari...@hyperreal.org
Subject cvs commit: jakarta-tomcat/src/share/org/apache/tomcat/util NetworkClassLoader.java
Date Fri, 26 Nov 1999 09:03:46 GMT
harishp     99/11/26 01:03:46

  Modified:    src/share/org/apache/tomcat/core Container.java
  Added:       src/share/org/apache/tomcat/core ServletClassLoader.java
               src/share/org/apache/tomcat/util NetworkClassLoader.java
  Log:
  Added a new ServletClassLoader that is a lot meaner and cleaner than the
  earlier one. The previous one is still called ServletLoder, while this one
  is called ServletClassLoader. After a few weeks, once this class loader
  settles in, I will remove the old one (ServletLoader) from the core package.
  
  Also added NetworkClassLoader, I recommend that JspLoader (& any other
  class loaders) extend from this class loader. Firstly, it can load classes
  off any URL. Secondly, it is modelled after JDK 1.2 style class loader.
  
  Modified the servlet container to use this class loader instead of an
  earlier one.
  
  Revision  Changes    Path
  1.6       +3 -3      jakarta-tomcat/src/share/org/apache/tomcat/core/Container.java
  
  Index: Container.java
  ===================================================================
  RCS file: /home/cvs/jakarta-tomcat/src/share/org/apache/tomcat/core/Container.java,v
  retrieving revision 1.5
  retrieving revision 1.6
  diff -u -r1.5 -r1.6
  --- Container.java	1999/11/06 00:19:49	1.5
  +++ Container.java	1999/11/26 09:03:43	1.6
  @@ -74,7 +74,7 @@
   public class Container {
   
       private Context context;
  -    private ServletLoader servletLoader;
  +    private ServletClassLoader servletLoader;
       private Hashtable servlets = new Hashtable();
       private Hashtable prefixMappedServlets = new Hashtable();
       private Hashtable extensionMappedServlets = new Hashtable();
  @@ -92,9 +92,9 @@
   	return context;
       }
   
  -    ServletLoader getLoader() {
  +    ServletClassLoader getLoader() {
   	if(servletLoader == null) {
  -	    servletLoader = new ServletLoader(this);
  +	    servletLoader = new ServletClassLoader(this);
   	}
   
   	return servletLoader;
  
  
  
  1.1                  jakarta-tomcat/src/share/org/apache/tomcat/core/ServletClassLoader.java
  
  Index: ServletClassLoader.java
  ===================================================================
  /*
   * $Header: /home/cvs/jakarta-tomcat/src/share/org/apache/tomcat/core/ServletClassLoader.java,v
1.1 1999/11/26 09:03:43 harishp Exp $
   * $Revision: 1.1 $
   * $Date: 1999/11/26 09:03:43 $
   *
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999 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 acknowlegement:  
   *       "This product includes software developed by the 
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written 
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * 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/>.
   *
   * [Additional notices, if required by prior licensing conditions]
   *
   */ 
  
  package org.apache.tomcat.core;
  
  import org.apache.tomcat.util.*;
  import java.io.*;
  import java.net.*;
  import java.util.*;
  
  /**
   * This class now extends NetworkClassLoader. Previous
   * implementation of ServletClassLoader is called ServletLoader.
   * This implementation is a complete rewrite of the earlier
   * class loader. This should speed up performance compared
   * to the earlier class loader.
   *
   * @author Harish Prabandham
   */
  
  //
  // WARNING: Some of the APIs in this class are used by J2EE. 
  // Please talk to harishp@eng.sun.com before making any changes.
  //
  class ServletClassLoader extends NetworkClassLoader {
      private Container container;
      
      ServletClassLoader(Container container) {
          super(container.getContext().getClassLoader());
  	this.container = container;
          initURLs(); 
      }
  
      private void initURLs() {
          URL baseURL = container.getServletBase();
          String protocol = baseURL.getProtocol();
          int port = baseURL.getPort();
          String hostname = baseURL.getHost();
          
          String basepath = baseURL.getFile();
  
          // The classes directory...
          for(Enumeration e = container.getClassPaths();
              e.hasMoreElements(); ) {
              String cpath = (String) e.nextElement();
              try {
                  URL classesURL = new URL(protocol,hostname,port,
                                           basepath + cpath + "/");
                  addURL(classesURL);
              }catch(MalformedURLException mue) {
              }
          }
  
          // The jars in the lib directory...
          // This will not work if the URL is not a file URL.
          // An alternate way of figuring out the jar files should
          // be specified in the spec. Probably in the deployment
          // descriptor's web.xml ???
          for(Enumeration e = container.getLibPaths();
              e.hasMoreElements(); ) {
              String libpath = (String) e.nextElement();
              File f =  new File(basepath + libpath + "/");
              Vector jars = new Vector();
              getJars(jars, f);
              
              for(int i=0; i < jars.size(); ++i) {
                  try {
                      String jarfile = (String) jars.elementAt(i);
                      URL jarURL = new URL(protocol,hostname,port,
                                           basepath + jarfile);
                      addURL(jarURL);
                  }catch(MalformedURLException mue) {
                  }
              }
          }
      }
  
      synchronized Class loadServlet(ServletWrapper wrapper, String name)
          throws ClassNotFoundException {
  	Class clazz = loadClass(name, true);
  	// do whatever marking we need to do
  	return clazz;
      }
  
      protected synchronized Class loadClass(String name, boolean resolve)
          throws ClassNotFoundException {
          // This is a bad idea. Unfortunately the class loader may
          // be set on the context at any point.
          setParent(container.getContext().getClassLoader());
          return super.loadClass(name, resolve);
      }
  
      String getClassPath() {
          URL[] urls = getURLs();
          String separator = System.getProperty("path.separator", ":");
  
          String cpath = "";
  
          for(int i=0; i < urls.length; ++i) {
              cpath = cpath + separator + urls[i].getFile();
          }
  
          return cpath;
      }
  
      private void getJars(Vector v, File f) {
          FilenameFilter jarfilter = new JarFileFilter();
          FilenameFilter dirfilter = new DirectoryFilter();
          
          if(f.exists() && f.isDirectory() && f.isAbsolute()) {
              String[] jarlist = f.list(jarfilter);
  
              for(int i=0; (jarlist != null) && (i < jarlist.length); ++i) {
                  v.addElement(jarlist[i]);
              }
  
              String[] dirlist = f.list(dirfilter);
  
              for(int i=0; (dirlist != null) && (i < dirlist.length); ++i) {
                  File dir = new File(f, dirlist[i]);
                  getJars(v, dir);
              }
          }
      }
  }
  
  
  class JarFileFilter implements FilenameFilter {
  
      public boolean accept(File dir, String fname) {
          if(fname.endsWith(".jar"))
              return true;
  
          return false;
      }
  }
  
  class DirectoryFilter implements FilenameFilter {
  
      public boolean accept(File dir, String fname) {
          File f = new File(dir, fname);
          if(f.isDirectory())
              return true;
  
          return false;
      }
  }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  1.1                  jakarta-tomcat/src/share/org/apache/tomcat/util/NetworkClassLoader.java
  
  Index: NetworkClassLoader.java
  ===================================================================
  /*
   * $Header: /home/cvs/jakarta-tomcat/src/share/org/apache/tomcat/util/NetworkClassLoader.java,v
1.1 1999/11/26 09:03:46 harishp Exp $
   * $Revision: 1.1 $
   * $Date: 1999/11/26 09:03:46 $
   *
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999 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 acknowlegement:  
   *       "This product includes software developed by the 
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written 
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * 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/>.
   *
   * [Additional notices, if required by prior licensing conditions]
   *
   */ 
  
  package org.apache.tomcat.util;
  
  import java.util.zip.*;
  import java.net.*;
  import java.util.*;
  import java.io.*;
  
  /**
   * The correct name for this class should be URLClassLoader.
   * But there is already a class by that name in JDK1.2.
   *
   * I have had quite a few problems with URLClassLoader in
   * past, so I ended up writing this ClassLoader. I found that
   * the Java 2's URLClassLoader, does not close the Jar file once
   * opened. It is a pretty good optimization step, but if you
   * modify the class in the jar file, it does not pick it up. Some
   * operating systems may not let you modify the jar file while it is
   * still open. IMHO, it does make sense to close the jar file
   * after you are done reading the class data. But this approach may not
   * get you the performance of the URLClassLoader, but it works in all
   * cases and also runs on JDK1.1
   *
   * @author Harish Prabandham
   */
  public class NetworkClassLoader extends ClassLoader {
      private ClassLoader parent = null; // parent classloader
      private Hashtable classCache = new Hashtable();
      private Vector urlset = new Vector();
  
      /**
       * Creates a new instance of the class loader.
       * @param delegate/parent class loader.
       */
      public NetworkClassLoader(ClassLoader parent) {
          setParent(parent);
      }
  
      /**
       * Sets the parent/delegate class loader.
       * @param delegate/parent class loader.
       */
      protected final void setParent(ClassLoader parent) {
          this.parent = parent;
      }
  
      /**
       * Adds the given URL to this class loader. If the URL
       * ends with "/", then it is assumed to be a directory
       * otherwise, it is assumed to be a zip/jar file.
       * @param URL where to look for the classes.
       */
      public void addURL(URL url) {
          System.out.println("Adding url: " + url);
          if(!urlset.contains(url)) {
              urlset.addElement(url);
          }
      }
  
      /**
       * @return The URLs where this class loader looks for classes.
       */
      public URL[] getURLs() {
          URL[] urls = new URL[urlset.size()];
          urlset.copyInto(urls);
          return urls;
      }
  
      private byte[] loadResource(URL url, String resourceName)
          throws MalformedURLException, IOException {
          byte[] bytes = null;
  
          if(url.getFile().endsWith("/")) {
              // It is a directory 
              URL realURL = new URL(url.getProtocol(), url.getHost(),
                                    url.getFile() + resourceName);
  
              InputStream istream = realURL.openStream();
              bytes = getBytes(istream);
              try{istream.close();}catch(Exception e){}
              
          } else {
              // It is a zip/jar file.
              InputStream istream = url.openStream();
              ZipInputStream zstream = new ZipInputStream(istream);
              ZipEntry entry = null;
  
              while( (entry = zstream.getNextEntry()) != null) {
                  System.out.println("Entry=" + entry.getName());
                  if(!entry.isDirectory() &&
                     entry.getName().equals(resourceName)) {
                      bytes = getBytes(zstream);
                      zstream.close();
                      break;
                  }
  
                  zstream.closeEntry();
              }
  
              try{istream.close();}catch(Exception e){}
          }
  
          return bytes;
      }
  
      private byte[] loadResource(String resource) {
          byte[] barray = null;
          for(Enumeration e = urlset.elements(); e.hasMoreElements();) {
              URL url = (URL) e.nextElement();
  
              try {
                  barray = loadResource(url, resource);
              } catch(Exception ex) {
              } finally {
                  if(barray != null)
                      break;
              }
          }
  
          return barray;
      }
  
      private byte[] getBytes(InputStream istream) throws IOException {
          byte[] buf = new byte[1024];
          int num = 0;
          ByteArrayOutputStream bout = new ByteArrayOutputStream();
  
          while( (num = istream.read(buf)) != -1) {
              bout.write(buf, 0, num);
          }
  
          return bout.toByteArray();
      }
  
      private byte[] loadClassData(String classname) {
          String resourceName = classname.replace('.', '/') + ".class";
          return loadResource(resourceName);
      }
  
      /**
       * @return The resource as the input stream if such a resource
       * exists, otherwise returns null.
       */
      public InputStream getResourceAsStream(String name) {
          InputStream istream = null;
          
          // Algorithm:
          //
          // 1. first check the system path for the resource
          // 2. next  check the  delegate/parent class loader for the resource
          // 3. then attempt to get the resource from the url set.
          //
  
          // Lets check the system path for the resource.
          istream = getSystemResourceAsStream(name);
          if(istream != null)
              return istream;
  
          // Lets check the parent/delegate class loader for the resource.
          if(parent != null) {
              istream = parent.getResourceAsStream(name);
              if(istream != null)
                  return istream;
          }
  
          // Lets load it ourselves.
          byte[] data = loadResource(name);
          if(data != null) {
              istream = new ByteArrayInputStream(data);
          }
  
          return istream;
      }
  
      /**
       * java.lang.ClassLoader's defineClass method is final, so the
       * its subclasses cannot override this method. But, this class
       * instead calls this method in the loadClass() instead.
       * @param The name of the class without ".class" extension.
       * @param The class data bytes.
       * @return The class object.
       */
      protected Class defineClass(String classname, byte[] classdata) {
          return defineClass(classname, classdata, 0, classdata.length);
      }
  
      protected synchronized Class loadClass(String name, boolean resolve)
          throws ClassNotFoundException {
          Class c = null;
  
          // Algorithm: (Please do not change the order; unless you
          // have a good reason to do so).
          //
          // 1. first check the system class loader.
          // 2. next  check the  delegate/parent class loader.
          // 3. next  check the class cache
          // 4. then attempt to load classes from the URL set.
          //
          
          // Lets see if the class is in system class loader.
          try {
              c = findSystemClass(name);
          }catch(ClassNotFoundException cnfe) {
          }finally {
              if(c != null)
                  return c;
          }
  
          // Lets see if the class is in parent class loader.
          try {
              if(parent != null)
                  c = parent.loadClass(name);
          }catch(ClassNotFoundException cnfe) {
          }finally {
              if(c != null)
                  return c;
          }
  
          // Lets see if the class is in the cache..
          c = (Class) classCache.get(name);
  
          if(c != null)
              return c;
  
  
          // Lets see if we find the class all by ourselves.
          byte[] data = loadClassData(name);
  
          if(data != null) {
              // we did !!
              c = defineClass(name, data);
              classCache.put(name, c);
              if(resolve)
                  resolveClass(c);
          } else {
              // We are out of luck at this point...
              throw new ClassNotFoundException(name);
          }
  
          return c;
      }
  
      /**
       * This method resets this ClassLoader's state. It completely
       * removes all the URLs and classes in this class loader cache. 
       */
      protected final void clear() {
          urlset.removeAllElements();
          classCache.clear();
      }
  
      /**
       * This method resets this ClassLoader's state and resets the
       * references for garbage collection.
       */
      protected void finalize() throws Throwable {
          // Cleanup real well. Otherwise, this can be
          // a major source of memory leaks...
  
          // remove all the urls & class entries.
          clear();
          
          parent = null;
          urlset = null;
          classCache = null;
      }
  }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

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