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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.maven.plugin;
20  
21  import org.apache.maven.plugin.logging.Log;
22  
23  /**
24   * This interface forms the contract required for <code>Mojos</code> to interact with the <code>Maven</code>
25   * infrastructure.<br>
26   * It features an <code>execute()</code> method, which triggers the Mojo's build-process behavior, and can throw
27   * a MojoExecutionException or MojoFailureException if error conditions occur.<br>
28   * Also included is the <code>setLog(...)</code> method, which simply allows Maven to inject a logging mechanism which
29   * will allow the Mojo to communicate to the outside world through standard Maven channels.
30   *
31   * @author Jason van Zyl
32   */
33  public interface Mojo {
34      /** The component <code>role</code> hint for Plexus container */
35      String ROLE = Mojo.class.getName();
36  
37      /**
38       * Perform whatever build-process behavior this <code>Mojo</code> implements.<br>
39       * This is the main trigger for the <code>Mojo</code> inside the <code>Maven</code> system, and allows
40       * the <code>Mojo</code> to communicate errors.
41       *
42       * @throws MojoExecutionException if an unexpected problem occurs.
43       * Throwing this exception causes a "BUILD ERROR" message to be displayed.
44       * @throws MojoFailureException if an expected problem (such as a compilation failure) occurs.
45       * Throwing this exception causes a "BUILD FAILURE" message to be displayed.
46       */
47      void execute() throws MojoExecutionException, MojoFailureException;
48  
49      /**
50       * Inject a standard <code>Maven</code> logging mechanism to allow this <code>Mojo</code> to communicate events
51       * and feedback to the user.
52       *
53       * @param log a new logger
54       */
55      // TODO not sure about this here, and may want a getLog on here as well/instead
56      void setLog(Log log);
57  
58      /**
59       * Furnish access to the standard Maven logging mechanism which is managed in this base class.
60       *
61       * @return a log4j-like logger object which allows plugins to create messages at levels of <code>"debug"</code>,
62       * <code>"info"</code>, <code>"warn"</code>, and <code>"error"</code>. This logger is the accepted means to display
63       * information to the user.
64       */
65      Log getLog();
66  }