Mercurial > lasercutter

     1 /**

     2  *   Copyright (c) Rich Hickey. All rights reserved.

     3  *   The use and distribution terms for this software are covered by the

     4  *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

     5  *   which can be found in the file epl-v10.html at the root of this distribution.

     6  *   By using this software in any fashion, you are agreeing to be bound by

     7  * 	 the terms of this license.

     8  *   You must not remove this notice, or any other, from this software.

     9  **/

    10 

    11 /* rich Aug 21, 2007 */

    12 

    13 package clojure.lang;

    14 

    15 import java.util.HashMap;

    16 import java.util.Map;

    17 import java.util.concurrent.ConcurrentHashMap;

    18 import java.net.URLClassLoader;

    19 import java.net.URL;

    20 import java.lang.ref.ReferenceQueue;

    21 import java.lang.ref.SoftReference;

    22 

    23 public class DynamicClassLoader extends URLClassLoader{

    24 HashMap<Integer, Object[]> constantVals = new HashMap<Integer, Object[]>();

    25 static ConcurrentHashMap<String, SoftReference<Class>>classCache =

    26         new ConcurrentHashMap<String, SoftReference<Class> >();

    27 

    28 static final URL[] EMPTY_URLS = new URL[]{};

    29 

    30 static final ReferenceQueue rq = new ReferenceQueue();

    31 

    32 public DynamicClassLoader(){

    33     //pseudo test in lieu of hasContextClassLoader()

    34 	super(EMPTY_URLS,(Thread.currentThread().getContextClassLoader() == null ||

    35                 Thread.currentThread().getContextClassLoader() == ClassLoader.getSystemClassLoader())?

    36                 Compiler.class.getClassLoader():Thread.currentThread().getContextClassLoader());

    37 }

    38 

    39 public DynamicClassLoader(ClassLoader parent){

    40 	super(EMPTY_URLS,parent);

    41 }

    42 

    43 public Class defineClass(String name, byte[] bytes, Object srcForm){

    44 	Util.clearCache(rq, classCache);

    45 	Class c = defineClass(name, bytes, 0, bytes.length);

    46     classCache.put(name, new SoftReference(c,rq));

    47     return c;

    48 }

    49 

    50 protected Class<?> findClass(String name) throws ClassNotFoundException{

    51     SoftReference<Class> cr = classCache.get(name);

    52 	if(cr != null)

    53 		{

    54 		Class c = cr.get();

    55         if(c != null)

    56             return c;

    57 		}

    58 	return super.findClass(name);

    59 }

    60 

    61 public void registerConstants(int id, Object[] val){

    62 	constantVals.put(id, val);

    63 }

    64 

    65 public Object[] getConstants(int id){

    66 	return constantVals.get(id);

    67 }

    68 

    69 public void addURL(URL url){

    70 	super.addURL(url);

    71 }

    72 

    73 }
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 21 Aug 2010 06:25:44 -0400
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