ClassLoadingHook


1   /*******************************************************************************
2    * Copyright (c) 2005, 2006 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  
12  package org.eclipse.osgi.baseadaptor.hooks;
13  
14  import java.security.ProtectionDomain  ;
15  import java.util.ArrayList  ;
16  import org.eclipse.osgi.baseadaptor.BaseData;
17  import org.eclipse.osgi.baseadaptor.HookRegistry;
18  import org.eclipse.osgi.baseadaptor.bundlefile.BundleEntry;
19  import org.eclipse.osgi.baseadaptor.loader.*;
20  import org.eclipse.osgi.framework.adaptor.*;
21  
22  /**
23   * A ClassLoadingHook hooks into the <code>ClasspathManager</code> class.
24   * @see ClasspathManager
25   * @see HookRegistry#getClassLoadingHooks()
26   * @see HookRegistry#addClassLoadingHook(ClassLoadingHook)
27   * @since 3.2
28   */
29  public interface ClassLoadingHook {
30      /**
31       * Gets called by a classpath manager before defining a class.  This method allows a class loading hook 
32       * to process the bytes of a class that is about to be defined.
33       * @param name the name of the class being defined
34       * @param classbytes the bytes of the class being defined
35       * @param classpathEntry the ClasspathEntry where the class bytes have been read from.
36       * @param entry the BundleEntry source of the class bytes
37       * @param manager the class path manager used to define the requested class
38       * @return a modified array of classbytes or null if the original bytes should be used.
39       */
40      byte[] processClass(String   name, byte[] classbytes, ClasspathEntry classpathEntry, BundleEntry entry, ClasspathManager manager);
41  
42      /**
43       * Gets called by a classpath manager when looking for ClasspathEntry objects.  This method allows 
44       * a classloading hook to add additional ClasspathEntry objects
45       * @param cpEntries the list of ClasspathEntry objects currently available for the requested classpath
46       * @param cp the name of the requested classpath
47       * @param hostmanager the classpath manager the requested ClasspathEntry is for
48       * @param sourcedata the source bundle data of the requested ClasspathEntry
49       * @param sourcedomain the source domain of the requested ClasspathEntry
50       * @return true if a ClasspathEntry has been added to cpEntries
51       */
52      boolean addClassPathEntry(ArrayList   cpEntries, String   cp, ClasspathManager hostmanager, BaseData sourcedata, ProtectionDomain   sourcedomain);
53  
54      /**
55       * Gets called by a base data during {@link BundleData#findLibrary(String)}.
56       * A base data will call this method for each configured class loading hook until one 
57       * class loading hook returns a non-null value.  If no class loading hook returns 
58       * a non-null value then the base data will return null.
59       * @param data the base data to find a native library for.
60       * @param libName the name of the native library.
61       * @return The absolute path name of the native library or null.
62       */
63      String   findLibrary(BaseData data, String   libName);
64  
65      /**
66       * Gets called by the adaptor during {@link FrameworkAdaptor#getBundleClassLoaderParent()}.
67       * The adaptor will call this method for each configured class loading hook until one 
68       * class loading hook returns a non-null value.  If no class loading hook returns 
69       * a non-null value then the adaptor will perform the default behavior.
70       * @return the parent classloader to be used by all bundle classloaders or null.
71       */
72      public ClassLoader   getBundleClassLoaderParent();
73  
74      /**
75       * Gets called by a base data during 
76       * {@link BundleData#createClassLoader(ClassLoaderDelegate, BundleProtectionDomain, String[])}.
77       * The BaseData will call this method for each configured class loading hook until one data
78       * hook returns a non-null value.  If no class loading hook returns a non-null value then a 
79       * default implemenation of BundleClassLoader will be created.
80       * @param parent the parent classloader for the BundleClassLoader
81       * @param delegate the delegate for the bundle classloader
82       * @param domain the domian for the bundle classloader
83       * @param data the BundleData for the BundleClassLoader
84       * @param bundleclasspath the classpath for the bundle classloader
85       * @return a newly created bundle classloader
86       */
87      BaseClassLoader createClassLoader(ClassLoader   parent, ClassLoaderDelegate delegate, BundleProtectionDomain domain, BaseData data, String  [] bundleclasspath);
88  
89      /**
90       * Gets called by a classpath manager at the end of 
91       * {@link ClasspathManager#initialize()}.
92       * The classpath manager will call this method for each configured class loading hook after it 
93       * has been initialized.
94       * @param baseClassLoader the newly created bundle classloader
95       * @param data the BundleData associated with the bundle classloader
96       */
97      void initializedClassLoader(BaseClassLoader baseClassLoader, BaseData data);
98  }
99
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