001: /*
002: * JBoss, Home of Professional Open Source.
003: * Copyright 2006, Red Hat Middleware LLC, and individual contributors
004: * as indicated by the @author tags. See the copyright.txt file in the
005: * distribution for a full listing of individual contributors.
006: *
007: * This is free software; you can redistribute it and/or modify it
008: * under the terms of the GNU Lesser General Public License as
009: * published by the Free Software Foundation; either version 2.1 of
010: * the License, or (at your option) any later version.
011: *
012: * This software is distributed in the hope that it will be useful,
013: * but WITHOUT ANY WARRANTY; without even the implied warranty of
014: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015: * Lesser General Public License for more details.
016: *
017: * You should have received a copy of the GNU Lesser General Public
018: * License along with this software; if not, write to the Free
019: * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
020: * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
021: */
022: package org.jboss.ejb.plugins;
023:
024: import java.rmi.NoSuchObjectException;
025: import java.rmi.RemoteException;
026: import org.jboss.ejb.EnterpriseContext;
027:
028: /**
029: * SFSB cache for clustered environment. Mainly avoid "excessive" locking
030: * that can generate cluster-distributed deadlocks.
031: *
032: * @see org.jboss.ejb.plugins.StatefulSessionInstanceCache
033: *
034: * @author <a href="mailto:sacha.labourey@cogito-info.ch">Sacha Labourey</a>.
035: * @version $Revision: 57188 $
036: *
037: * <p><b>Revisions:</b>
038: *
039: * <p><b>19 decembre 2002 Sacha Labourey:</b>
040: * <ul>
041: * <li> First implementation </li>
042: * </ul>
043: */
044:
045: public class StatefulHASessionInstanceCache extends
046: StatefulSessionInstanceCache {
047:
048: // Constants -----------------------------------------------------
049:
050: // Attributes ----------------------------------------------------
051:
052: // Static --------------------------------------------------------
053:
054: // Constructors --------------------------------------------------
055:
056: // Public --------------------------------------------------------
057:
058: /**
059: * Remove an object from the local cache *without* any locking
060: * (synchronized, etc.) to avoid huge cluster-wide deadlock situations
061: * We have to unschedule passivation as well as the bean may be
062: * used on another node.
063: */
064: public void invalidateLocally(Object id) {
065: if (id == null)
066: return;
067:
068: try {
069: getCache().remove(id);
070: } catch (Exception e) {
071: log.debug(e);
072: }
073: }
074:
075: // Z implementation ----------------------------------------------
076:
077: // AbstractInstanceCache overrides -------------------------------
078:
079: /*
080: * Make less extensive use of global locking when state must be activated: it
081: * will most probably generate time-costly cluster-wide communication =>
082: * we must avoid globally locking the whole cache! Furthermore, The
083: * StatefulSessionInstanceInterceptor *already* locks concurrent access to the
084: * cache that targets the *same* SFSB identity
085: */
086: public EnterpriseContext get(Object id) throws RemoteException,
087: NoSuchObjectException {
088: if (id == null)
089: throw new IllegalArgumentException(
090: "Can't get an object with a null key");
091:
092: EnterpriseContext ctx = null;
093:
094: synchronized (getCacheLock()) {
095: ctx = (EnterpriseContext) getCache().get(id);
096: if (ctx != null) {
097: return ctx;
098: }
099: }
100:
101: // If the ctx is still null at this point, it means that we must activate it
102: // => we don't lock the cache during this operation
103: // StatefulSessionInstanceInterceptor prevents multiple accesses for the same id
104: //
105: try {
106: ctx = acquireContext();
107: setKey(id, ctx);
108: activate(ctx);
109: logActivation(id);
110: insert(ctx);
111: } catch (Exception x) {
112: if (ctx != null)
113: freeContext(ctx);
114: log.debug("Activation failure, id=" + id, x);
115: throw new NoSuchObjectException(x.getMessage());
116: }
117:
118: // FIXME marcf: How can this ever be reached? the ctx is always assigned
119: if (ctx == null)
120: throw new NoSuchObjectException(
121: "Can't find bean with id = " + id);
122:
123: return ctx;
124: }
125:
126: // Package protected ---------------------------------------------
127:
128: // Protected -----------------------------------------------------
129:
130: // Private -------------------------------------------------------
131:
132: // Inner classes -------------------------------------------------
133:
134: }
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