com.wandrell.pattern.command.CommandExecutor Maven / Gradle / Ivy
/**
* The MIT License (MIT)
*
* Copyright (c) 2014 the original author or authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package com.wandrell.pattern.command;
/**
* Interface for the command executor pattern. It is designed to work with the
* command pattern interfaces existing on this same package: {@link Command} ,
* {@link ResultCommand} and {@link UndoableCommand}.
*
* It is the executor's main job to receive one of these commands through its
* own {@link #execute(Command) execute} method and processing it by calling
* that same command's {@code execute} method, differentiating between the bare
* {@code Command}, which returns nothing, and the {@code ResultCommand}, which
* generates a value during it's execution.
*
* For the first a {@link #execute(Command) execute(Command)}, with a
* {@code void} type, is used. While the second is executed through the
* {@link #execute(ResultCommand) execute(ResultCommand)} which will return the
* value generated by the command.
*
* Both methods are expected to execute the command as soon as they receive it.
* There can be additional operations, such as catching exceptions, injecting
* dependencies or setting up the environment. But these should be minimal, and
* never postpone the command's execution more than necessary.
*
* Additionally, implementations of {@link UndoableCommand} are handled through
* the {@link #undo(UndoableCommand) undo} method, which will take care of the
* command's own {@code undo} method in a similar way to the previously
* explained {@code execute} method.
*
* @author Bernardo Martínez Garrido
* @see Command
* @see ResultCommand
* @see UndoableCommand
*/
public interface CommandExecutor {
/**
* Executes the received {@code Command}.
*
* Any exception thrown by the command is expected to be caught and handled
* inside this method.
*
* @param command
* the {@code Command} to be executed
*/
public void execute(final Command command);
/**
* Executes the received {@code ResultCommand} and returns the value
* generated by this operation.
*
* Any exception thrown by the command is expected to be caught and handled
* inside this method.
*
* @param command
* the {@code ResultCommand} to be executed
* @param
* the type generated by the command
* @return an object generated by the command
*/
public V execute(final ResultCommand command);
/**
* Undoes the received {@code UndoableCommand}.
*
* If there is nothing to undo then the method is expected to act as if it
* ignored the command, doing nothing.
*
* Any exception thrown by the command is expected to be caught and handled
* inside this method.
*
* @param command
* the {@code UndoableCommand} to be undone
*/
public void undo(final UndoableCommand command);
}