[MRELEASE-1005] Extract ResourceGenerator from ReleasePhase
diff --git a/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/AbstractReleasePhase.java b/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/AbstractReleasePhase.java
index e03ff8b..672c18e 100644
--- a/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/AbstractReleasePhase.java
+++ b/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/AbstractReleasePhase.java
@@ -19,12 +19,9 @@
  * under the License.
  */
 
-import org.apache.maven.project.MavenProject;
 import org.apache.maven.shared.release.ReleaseResult;
 import org.codehaus.plexus.logging.AbstractLogEnabled;
 
-import java.util.List;
-
 /**
  * Base class for all phases.
  *
@@ -34,14 +31,6 @@
     extends AbstractLogEnabled
     implements ReleasePhase
 {
-    @Override
-    public ReleaseResult clean( List<MavenProject> reactorProjects )
-    {
-        // nothing to do by default
-
-        return getReleaseResultSuccess();
-    }
-
     protected void logInfo( ReleaseResult result, String message )
     {
         result.appendInfo( message );
diff --git a/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/ReleasePhase.java b/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/ReleasePhase.java
index d925ec6..1170856 100644
--- a/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/ReleasePhase.java
+++ b/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/ReleasePhase.java
@@ -63,11 +63,4 @@
                             List<MavenProject> reactorProjects )
         throws ReleaseExecutionException, ReleaseFailureException;
 
-    /**
-     * Clean up after a phase if it leaves any additional files in the checkout.
-     *
-     * @param reactorProjects the reactor projects
-     * @return the release result
-     */
-    ReleaseResult clean( List<MavenProject> reactorProjects );
 }
diff --git a/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/ResourceGenerator.java b/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/ResourceGenerator.java
new file mode 100644
index 0000000..8f85e3e
--- /dev/null
+++ b/maven-release-api/src/main/java/org/apache/maven/shared/release/phase/ResourceGenerator.java
@@ -0,0 +1,42 @@
+package org.apache.maven.shared.release.phase;
+
+/*
+ * 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.
+ */
+
+import java.util.List;
+
+import org.apache.maven.project.MavenProject;
+import org.apache.maven.shared.release.ReleaseResult;
+
+/**
+ * Additional interface for ReleasePhase if the phase generates resources, which should be cleaned up afterwards.
+ * 
+ * @author Robert Scholte
+ * @since 3.0.0
+ */
+public interface ResourceGenerator
+{
+    /**
+     * Clean up after a phase if it leaves any additional files in the checkout.
+     *
+     * @param reactorProjects the reactor projects
+     * @return the release result
+     */
+    ReleaseResult clean( List<MavenProject> reactorProjects );
+}
diff --git a/maven-release-manager/src/main/java/org/apache/maven/shared/release/DefaultReleaseManager.java b/maven-release-manager/src/main/java/org/apache/maven/shared/release/DefaultReleaseManager.java
index 1cbcb89..2eb77d6 100644
--- a/maven-release-manager/src/main/java/org/apache/maven/shared/release/DefaultReleaseManager.java
+++ b/maven-release-manager/src/main/java/org/apache/maven/shared/release/DefaultReleaseManager.java
@@ -34,6 +34,7 @@
 import org.apache.maven.shared.release.config.ReleaseDescriptorStoreException;
 import org.apache.maven.shared.release.config.ReleaseUtils;
 import org.apache.maven.shared.release.phase.ReleasePhase;
+import org.apache.maven.shared.release.phase.ResourceGenerator;
 import org.apache.maven.shared.release.strategy.Strategy;
 import org.codehaus.plexus.component.annotations.Component;
 import org.codehaus.plexus.component.annotations.Requirement;
@@ -539,8 +540,11 @@
         for ( String name : phases )
         {
             ReleasePhase phase = releasePhases.get( name );
-
-            phase.clean( cleanRequest.getReactorProjects() );
+            
+            if ( phase instanceof ResourceGenerator )
+            {
+                ( (ResourceGenerator) phase ).clean( cleanRequest.getReactorProjects() );
+            }
         }
 
         updateListener( cleanRequest.getReleaseManagerListener(), "cleanup", PHASE_END );
diff --git a/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/AbstractRewritePomsPhase.java b/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/AbstractRewritePomsPhase.java
index d068ce4..2a58da6 100644
--- a/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/AbstractRewritePomsPhase.java
+++ b/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/AbstractRewritePomsPhase.java
@@ -67,7 +67,7 @@
  * @author <a href="mailto:brett@apache.org">Brett Porter</a>
  */
 public abstract class AbstractRewritePomsPhase
-    extends AbstractReleasePhase
+    extends AbstractReleasePhase implements ResourceGenerator
 {
     /**
      * Tool that gets a configured SCM repository from release configuration.
@@ -141,8 +141,6 @@
     {
         ReleaseResult result = new ReleaseResult();
 
-        super.clean( reactorProjects );
-
         if ( reactorProjects != null )
         {
             for ( MavenProject project : reactorProjects )
diff --git a/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhase.java b/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhase.java
index 56966c9..bf07fd6 100644
--- a/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhase.java
+++ b/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhase.java
@@ -37,7 +37,7 @@
  */
 @Component( role = ReleasePhase.class, hint = "create-backup-poms" )
 public class CreateBackupPomsPhase
-    extends AbstractBackupPomsPhase
+    extends AbstractBackupPomsPhase implements ResourceGenerator
 {
     @Override
     public ReleaseResult execute( ReleaseDescriptor releaseDescriptor, ReleaseEnvironment releaseEnvironment,
diff --git a/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/GenerateReleasePomsPhase.java b/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/GenerateReleasePomsPhase.java
index 455f9b4..7b6004f 100644
--- a/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/GenerateReleasePomsPhase.java
+++ b/maven-release-manager/src/main/java/org/apache/maven/shared/release/phase/GenerateReleasePomsPhase.java
@@ -74,7 +74,7 @@
  */
 @Component( role = ReleasePhase.class, hint = "generate-release-poms" )
 public class GenerateReleasePomsPhase
-    extends AbstractReleasePomsPhase
+    extends AbstractReleasePomsPhase implements ResourceGenerator
 {
     private static final String FINALNAME_EXPRESSION = "${project.artifactId}-${project.version}";
 
diff --git a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/AbstractRewritingReleasePhaseTestCase.java b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/AbstractRewritingReleasePhaseTestCase.java
index 427371c..b28fa91 100644
--- a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/AbstractRewritingReleasePhaseTestCase.java
+++ b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/AbstractRewritingReleasePhaseTestCase.java
@@ -653,7 +653,7 @@
         throws Exception
     {
         // This occurs when it is release:perform run standalone. Just check there are no errors.
-        phase.clean( Collections.<MavenProject>emptyList() );
+        ( (ResourceGenerator) phase ).clean( Collections.<MavenProject>emptyList() );
     }
 
     protected ReleaseDescriptorBuilder createUnmappedConfiguration( List<MavenProject> reactorProjects )
diff --git a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhaseTest.java b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhaseTest.java
index 2ffa781..44e43ee 100644
--- a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhaseTest.java
+++ b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/CreateBackupPomsPhaseTest.java
@@ -101,7 +101,7 @@
     {
         List<MavenProject> projects = getReactorProjects( getTestPath( path ) );
 
-        phase.clean( projects );
+        ( (ResourceGenerator) phase ).clean( projects );
 
         testProjectBackups( projects, false );
     }
diff --git a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/ReleasePhaseStub.java b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/ReleasePhaseStub.java
index 69b3f8e..7d28bdf 100644
--- a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/ReleasePhaseStub.java
+++ b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/ReleasePhaseStub.java
@@ -32,7 +32,7 @@
  * @author <a href="mailto:brett@apache.org">Brett Porter</a>
  */
 public class ReleasePhaseStub
-    implements ReleasePhase
+    implements ReleasePhase, ResourceGenerator
 {
     /**
      * Whether the phase was simulated.
diff --git a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForBranchPhaseTest.java b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForBranchPhaseTest.java
index 6eb74b2..0eff85c 100644
--- a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForBranchPhaseTest.java
+++ b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForBranchPhaseTest.java
@@ -28,7 +28,6 @@
 import java.util.List;
 import java.util.Objects;
 
-import org.apache.maven.artifact.ArtifactUtils;
 import org.apache.maven.project.MavenProject;
 import org.apache.maven.shared.release.config.ReleaseDescriptorBuilder;
 import org.apache.maven.shared.release.config.ReleaseUtils;
@@ -130,7 +129,7 @@
 
         assertTrue( testFile.exists() );
 
-        phase.clean( reactorProjects );
+        ( (ResourceGenerator) phase ).clean( reactorProjects );
 
         assertFalse( testFile.exists() );
     }
@@ -147,7 +146,7 @@
         testFile.delete();
         assertFalse( testFile.exists() );
 
-        phase.clean( reactorProjects );
+        ( (ResourceGenerator) phase ).clean( reactorProjects );
 
         assertFalse( testFile.exists() );
     }
diff --git a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForDevelopmentPhaseTest.java b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForDevelopmentPhaseTest.java
index d8b9330..5fcc549 100644
--- a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForDevelopmentPhaseTest.java
+++ b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForDevelopmentPhaseTest.java
@@ -133,7 +133,7 @@
 
         assertTrue( testFile.exists() );
 
-        phase.clean( reactorProjects );
+        ( (ResourceGenerator) phase ).clean( reactorProjects );
 
         assertFalse( testFile.exists() );
     }
@@ -148,7 +148,7 @@
         testFile.delete();
         assertFalse( testFile.exists() );
 
-        phase.clean( reactorProjects );
+        ( (ResourceGenerator) phase ).clean( reactorProjects );
 
         assertFalse( testFile.exists() );
     }
diff --git a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForReleasePhaseTest.java b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForReleasePhaseTest.java
index d81b7a5..ebe9ef0 100644
--- a/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForReleasePhaseTest.java
+++ b/maven-release-manager/src/test/java/org/apache/maven/shared/release/phase/RewritePomsForReleasePhaseTest.java
@@ -31,7 +31,6 @@
 
 import org.apache.maven.project.MavenProject;
 import org.apache.maven.shared.release.config.ReleaseDescriptorBuilder;
-import org.apache.maven.shared.release.config.ReleaseStageVersions;
 import org.apache.maven.shared.release.config.ReleaseUtils;
 import org.apache.maven.shared.release.env.DefaultReleaseEnvironment;
 import org.apache.maven.shared.release.util.ReleaseUtil;
@@ -131,7 +130,7 @@
 
         assertTrue( testFile.exists() );
 
-        phase.clean( reactorProjects );
+        ( (ResourceGenerator) phase ).clean( reactorProjects );
 
         assertFalse( testFile.exists() );
     }
@@ -146,7 +145,7 @@
         testFile.delete();
         assertFalse( testFile.exists() );
 
-        phase.clean( reactorProjects );
+        ( (ResourceGenerator) phase ).clean( reactorProjects );
 
         assertFalse( testFile.exists() );
     }