com.gwtplatform.dispatch.server.actionhandler.ActionHandler Maven / Gradle / Ivy
/**
* Copyright 2011 ArcBees Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.gwtplatform.dispatch.server.actionhandler;
import com.gwtplatform.dispatch.server.ExecutionContext;
import com.gwtplatform.dispatch.shared.Action;
import com.gwtplatform.dispatch.shared.ActionException;
import com.gwtplatform.dispatch.shared.Result;
/**
* Instances of this interface will handle specific types of {@link Action}
* classes.
*
* Important! Your action handlers must be thread safe since they will be
* bound as singletons. For details, see
* http://code.google.com/p/google-guice/wiki/Scopes#Scopes_and_Concurrency.
*
* @param The type of the action extending {@link Action}.
* @param The type of the result extending {@link Result}.
* @author David Peterson
*/
public interface ActionHandler, R extends Result> {
/**
* Handles the specified action. If you want to build a compound action that
* can rollback automatically upon failure, call
* {@link ExecutionContext#execute(Action)}. See here
* for details.
*
* @param action The action.
* @param context The {@link ExecutionContext}.
* @return The {@link Result}.
* @throws ActionException if there is a problem performing the specified
* action.
*/
R execute(A action, ExecutionContext context) throws ActionException;
/**
* @return The type of {@link Action} supported by this handler.
*/
Class getActionType();
/**
* Undoes the specified action. If you want to build a compound action that
* can rollback automatically upon failure, call
* {@link ExecutionContext#undo(Action, Result)}. See here
* for details.
*
* @param action The action.
* @param result The result of the action.
* @param context The {@link ExecutionContext}.
* @throws ActionException if there is a problem performing the specified
* action.
*/
void undo(A action, R result, ExecutionContext context)
throws ActionException;
}