package org.apache.maven.enforcer.rule.api;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  */

 /**

  * Interface to be implemented by any rules executed by the enforcer.

  *

  * @author <a href="mailto:brianf@apache.org">Brian Fox</a>

  * @version $Id: EnforcerRule.java 987781 2010-08-21 16:23:40Z dennisl $

  */

 public interface EnforcerRule

 {

     /**

      * This is the interface into the rule. This method should throw an exception

      * containing a reason message if the rule fails the check. The plugin will

      * then decide based on the fail flag if it should stop or just log the

      * message as a warning.

      *

      * @param helper The helper provides access to the log, MavenSession and has

      * helpers to get common components. It is also able to lookup components

      * by class name.

      *

      * @throws EnforcerRuleException the enforcer rule exception

      */

     void execute( EnforcerRuleHelper helper )

         throws EnforcerRuleException;

     /**

      * This method tells the enforcer if the rule results may be cached. If the result is true,

      * the results will be remembered for future executions in the same build (ie children). Subsequent

      * iterations of the rule will be queried to see if they are also cacheable. This will allow the rule to be

      * uncached further down the tree if needed.

      *

      * @return <code>true</code> if rule is cacheable

      */

     boolean isCacheable();

     /**

      * Checks if cached result is valid.

      *

      * @param cachedRule the last cached instance of the rule. This is to be used by the rule to

      * potentially determine if the results are still valid (ie if the configuration has been overridden)

      *

      * @return <code>true</code> if the stored results are valid for the same id.

      */

     boolean isResultValid( EnforcerRule cachedRule );

     /**

      * If the rule is to be cached, this id is used as part of the key. This can allow rules to take parameters

      * that allow multiple results of the same rule to be cached.

      *

      * @return id to be used by the enforcer to determine uniqueness of cache results. The ids only need to be unique

      * within a given rule implementation as the full key will be [classname]-[id]

      */

     String getCacheId();

 }