| /* |
| * Copyright (c) 2001, 2003, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.corba.se.spi.extension ; |
| |
| import org.omg.CORBA.Policy ; |
| import org.omg.CORBA.LocalObject ; |
| import com.sun.corba.se.impl.orbutil.ORBConstants ; |
| |
| /** Policy used to implement servant caching optimization in the POA. |
| * Creating a POA with an instance pol of this policy where |
| * pol.getType() > NO_SERVANT_CACHING will cause the servant to be |
| * looked up in the POA and cached in the LocalClientRequestDispatcher when |
| * the ClientRequestDispatcher is colocated with the implementation of the |
| * objref. This greatly speeds up invocations at the cost of violating the |
| * POA semantics. In particular, every request to a particular objref |
| * must be handled by the same servant. Note that this is typically the |
| * case for EJB implementations. |
| * <p> |
| * If servant caching is used, there are two different additional |
| * features of the POA that are expensive: |
| * <ol> |
| * <li>POA current semantics |
| * <li>Proper handling of POA destroy. |
| * <ol> |
| * POA current semantics requires maintaining a ThreadLocal stack of |
| * invocation information that is always available for POACurrent operations. |
| * Maintaining this stack is expensive on the timescale of optimized co-located |
| * calls, so the option is provided to turn it off. Similarly, causing |
| * POA.destroy() calls to wait for all active calls in the POA to complete |
| * requires careful tracking of the entry and exit of invocations in the POA. |
| * Again, tracking this is somewhat expensive. |
| */ |
| public class ServantCachingPolicy extends LocalObject implements Policy |
| { |
| /** Do not cache servants in the ClientRequestDispatcher. This will |
| * always support the full POA semantics, including changing the |
| * servant that handles requests on a particular objref. |
| */ |
| public static final int NO_SERVANT_CACHING = 0 ; |
| |
| /** Perform servant caching, preserving POA current and POA destroy semantics. |
| * We will use this as the new default, as the app server is making heavier use |
| * now of POA facilities. |
| */ |
| public static final int FULL_SEMANTICS = 1 ; |
| |
| /** Perform servant caching, preservent only POA current semantics. |
| * At least this level is required in order to support selection of ObjectCopiers |
| * for co-located RMI-IIOP calls, as the current copier is stored in |
| * OAInvocationInfo, which must be present on the stack inside the call. |
| */ |
| public static final int INFO_ONLY_SEMANTICS = 2 ; |
| |
| /** Perform servant caching, not preserving POA current or POA destroy semantics. |
| */ |
| public static final int MINIMAL_SEMANTICS = 3 ; |
| |
| private static ServantCachingPolicy policy = null ; |
| private static ServantCachingPolicy infoOnlyPolicy = null ; |
| private static ServantCachingPolicy minimalPolicy = null ; |
| |
| private int type ; |
| |
| public String typeToName() |
| { |
| switch (type) { |
| case FULL_SEMANTICS: |
| return "FULL" ; |
| case INFO_ONLY_SEMANTICS: |
| return "INFO_ONLY" ; |
| case MINIMAL_SEMANTICS: |
| return "MINIMAL" ; |
| default: |
| return "UNKNOWN(" + type + ")" ; |
| } |
| } |
| |
| public String toString() |
| { |
| return "ServantCachingPolicy[" + typeToName() + "]" ; |
| } |
| |
| private ServantCachingPolicy( int type ) |
| { |
| this.type = type ; |
| } |
| |
| public int getType() |
| { |
| return type ; |
| } |
| |
| /** Return the default servant caching policy. |
| */ |
| public synchronized static ServantCachingPolicy getPolicy() |
| { |
| return getFullPolicy() ; |
| } |
| |
| public synchronized static ServantCachingPolicy getFullPolicy() |
| { |
| if (policy == null) |
| policy = new ServantCachingPolicy( FULL_SEMANTICS ) ; |
| |
| return policy ; |
| } |
| |
| public synchronized static ServantCachingPolicy getInfoOnlyPolicy() |
| { |
| if (infoOnlyPolicy == null) |
| infoOnlyPolicy = new ServantCachingPolicy( INFO_ONLY_SEMANTICS ) ; |
| |
| return infoOnlyPolicy ; |
| } |
| |
| public synchronized static ServantCachingPolicy getMinimalPolicy() |
| { |
| if (minimalPolicy == null) |
| minimalPolicy = new ServantCachingPolicy( MINIMAL_SEMANTICS ) ; |
| |
| return minimalPolicy ; |
| } |
| |
| public int policy_type () |
| { |
| return ORBConstants.SERVANT_CACHING_POLICY ; |
| } |
| |
| public org.omg.CORBA.Policy copy () |
| { |
| return this ; |
| } |
| |
| public void destroy () |
| { |
| // NO-OP |
| } |
| } |