org.glassfish.internal.api.UndoableCommand Maven / Gradle / Ivy
Show all versions of payara-micro Show documentation
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2010-2012 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package org.glassfish.internal.api;
import com.sun.enterprise.config.serverbeans.Server;
import org.glassfish.api.ActionReport;
import org.glassfish.api.admin.*;
import java.util.List;
/**
* Interface that augment the AdminCommand responsibilities by adding the ability
* to undo a previously successful execution of an administrative command.
*
* The ability to rollback is not meant to be used as an exception handling
* mechanism while in the {@link AdminCommand#execute(AdminCommandContext)} invocation.
* The ability to rollback is meant for undoing a successful command execution that
* need to be roll-backed for reasons outside of the knowledge of the command
* implementation.
*
*
Roll-backing can be very useful in clustering mode where actions can be performed
* successfully on some instances but fail on others necessitating to rollback the
* entire set of instances to a state previous to the action execution.
*
*
The implementations of this interface must retain any pertinent information necessary
* to undo the command within its instance context. Therefore all UndoableCommand implementations
* must have a {@link org.glassfish.hk2.api.PerLookup} scope otherwise the system will flag it
* as an error and will refuse to execute the command.
*
*
An undo-able command has a slightly more complicated set of phases execution as compared
* to the AdminCommand.
*
*
During the first phase, called the prepare phase, the framework will call
* this command prepare method as well as all supplemented commands prepare methods (if such
* supplemented commands implement the UndoableCommand interface). If the prepare phase is
* not successful, the command execution stops here and the command feedback is returned to the
* initiator.
*
*
Once the prepare phase has succeeded, the normal {@link AdminCommand#execute(AdminCommandContext)}
* method is invoked (and any supplemented methods).
*
*
If the framework is electing that successful commands execution need to be rolled back, it will
* call the {@link #undo(AdminCommandContext, ParameterMap, List)} method on the same instance that was used for the
* {@link #execute(AdminCommandContext)} invocation, as well as any supplemented commands that implement
* this interface.
*
* @author Jerome Dochez
*/
public interface UndoableCommand extends AdminCommand {
/**
* Checks whether the command execution has a chance of success before the execution is
* attempted. This could be useful in clustering environment where you must check certain
* pre-conditions before attempting to run an administrative change.
*
* For instance, the change-admin-password should probably not be attempted if all the
* servers instances are on-line and can be notified of the change.
*
*
No changes to the configuration should be made within the implementation of the
* prepare method since {@link #undo(AdminCommandContext, ParameterMap, List)} will not be called if the command
* execution stops at the prepare phase.
*
* Note that if, as part of prepare, remote instances have to be contacted, then it is the responsibility of
* the command implementation to invoke remote instaces for such verification.
*
* The framework will call prepare() method in DAS before execution of the main command
* and the execution of the main command will happen only if the prepare() call returns ActionReport.ExitCode.SUCCESS
* on DAS.
*
* @param context the command's context
* @param parameters parameters to the commands.
*/
@IfFailure(FailurePolicy.Error)
public ActionReport.ExitCode prepare(AdminCommandContext context, ParameterMap parameters);
/**
* Undo a previously successful execution of the command implementation. The context
* for undoing the administrative operation should be obtained from either the
* parameters passed to the command execution or the command instance context.
* The list of servers indicates to the command implementation on which servers the command succeeded
* The command implementation is guaranteed that the {@link #undo(AdminCommandContext, ParameterMap, List)}
* is called on DAS if the main command execution failed on one instance but it is the responsiblity of the command
* implementation to invoke remote instances to do the actual undo if required
*
* @param context the command's context
* @param parameters parameters passed to the command.
* @param instances instances on which the command succeeded
*/
public void undo(AdminCommandContext context, ParameterMap parameters, List instances);
}