001: /*****************************************************************************
002: * Java Plug-in Framework (JPF)
003: * Copyright (C) 2004-2007 Dmitry Olshansky
004: *
005: * This library is free software; you can redistribute it and/or
006: * modify it under the terms of the GNU Lesser General Public
007: * License as published by the Free Software Foundation; either
008: * version 2.1 of the License, or (at your option) any later version.
009: *
010: * This library is distributed in the hope that it will be useful,
011: * but WITHOUT ANY WARRANTY; without even the implied warranty of
012: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
013: * Lesser General Public License for more details.
014: *
015: * You should have received a copy of the GNU Lesser General Public
016: * License along with this library; if not, write to the Free Software
017: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
018: *****************************************************************************/package org.java.plugin.standard;
019:
020: import org.java.plugin.ObjectFactory;
021: import org.java.plugin.Plugin;
022: import org.java.plugin.PluginClassLoader;
023: import org.java.plugin.PluginLifecycleException;
024: import org.java.plugin.PluginManager;
025: import org.java.plugin.registry.PluginDescriptor;
026: import org.java.plugin.util.ExtendedProperties;
027:
028: /**
029: * Manager class that handles plug-in life cycle related logic. This class is
030: * part of standard implementation of plug-in manager, other implementations may
031: * not use it at all. The main purpose of this class is to simplify
032: * customization of plug-in manager behavior.
033: * @version $Id$
034: */
035: public abstract class PluginLifecycleHandler {
036: private PluginManager manager;
037:
038: /**
039: * Initializes this handler instance. This method called once during this
040: * handler instance life cycle.
041: * @param aManager a plug-in manager, this handler is "connected" to
042: */
043: protected void init(PluginManager aManager) {
044: manager = aManager;
045: }
046:
047: /**
048: * @return instance of plug-in manager, this handler is "connected" to
049: */
050: protected PluginManager getPluginManager() {
051: return manager;
052: }
053:
054: /**
055: * Configures this handler instance. Note that this method should be called
056: * once before {@link #init(PluginManager)}, usually this is done in
057: * {@link ObjectFactory object factory} implementation.
058: * @param config handler configuration data
059: */
060: protected abstract void configure(ExtendedProperties config);
061:
062: /**
063: * This method should create new instance of class loader for given plug-in.
064: * @param descr plug-in descriptor
065: * @return class loader instance for given plug-in
066: */
067: protected abstract PluginClassLoader createPluginClassLoader(
068: PluginDescriptor descr);
069:
070: /**
071: * This method should create new instance of plug-in class. No initializing
072: * logic should be executed in new class instance during this method call.
073: * <br>
074: * Note that this method will NOT be called for those plug-ins that have NO
075: * class declared in plug-in descriptor i.e., method
076: * {@link PluginDescriptor#getPluginClassName()} returns blank string or
077: * <code>null</code>.
078: * @param descr plug-in descriptor
079: * @return new not initialized instance of plug-in class
080: * @throws PluginLifecycleException if plug-in class can't be instantiated
081: * for some reason
082: */
083: protected abstract Plugin createPluginInstance(
084: PluginDescriptor descr) throws PluginLifecycleException;
085:
086: /**
087: * This method will be called by {@link PluginManager} just before starting
088: * plug-in. Put here any "initializing" logic that should be executed before
089: * plug-in start.
090: * @param plugin plug-in being starting
091: * @throws PluginLifecycleException if plug-in can't be "initialized"
092: */
093: protected abstract void beforePluginStart(final Plugin plugin)
094: throws PluginLifecycleException;
095:
096: /**
097: * This method will be called by {@link PluginManager} just after stopping
098: * plug-in. Put here any "un-initializing" logic that should be executed
099: * after plug-in stop.
100: * @param plugin plug-in being stopping
101: * @throws PluginLifecycleException if plug-in can't be "un-initialized"
102: */
103: protected abstract void afterPluginStop(final Plugin plugin)
104: throws PluginLifecycleException;
105:
106: /**
107: * Should dispose all resources allocated by this handler instance. No
108: * methods will be called for this class instance after executing this
109: * method.
110: */
111: protected abstract void dispose();
112: }
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