o Added model normalizer for things like merging duplicate plugin declarations

git-svn-id: https://svn.apache.org/repos/asf/maven/components/branches/MNG-2766@773869 13f79535-47bb-0310-9956-ffa450edef68

maven-core/src/main/java/org/apache/maven/project/DefaultMavenProjectBuilder.java

@@ -42,6 +42,7 @@
 import org.apache.maven.model.interpolator.Interpolator;
 import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
 import org.apache.maven.model.lifecycle.LifecycleBindingsInjector;
+import org.apache.maven.model.normalization.Normalizer;
 import org.apache.maven.model.plugin.PluginConfigurationExpander;
 import org.apache.maven.profiles.DefaultProfileManager;
 import org.apache.maven.profiles.ProfileActivationException;
@@ -77,7 +78,10 @@ public class DefaultMavenProjectBuilder
     private RepositorySystem repositorySystem;
 
     @Requirement
-    List<ModelEventListener> listeners;
+    private List<ModelEventListener> listeners;
+
+    @Requirement
+    private Normalizer normalizer;
 
     @Requirement
     private Interpolator interpolator;
@@ -390,6 +394,11 @@ else if ( isParentLocal( domainModel.getRelativePathOfParent(), pomFile.getParen
             domainModels.addAll( mavenParents );
         }
 
+        for ( DomainModel domain : domainModels )
+        {
+            normalizer.mergeDuplicates( domain.getModel() );
+        }
+
         domainModels.add( new DomainModel( getSuperModel(), false ) );
         List<DomainModel> profileModels = new ArrayList<DomainModel>();
         //Process Profiles

maven-core/src/test/resources/org/apache/maven/project/ProjectClasspathTest.xml

@@ -36,6 +36,11 @@
           <role-hint>default</role-hint>
           <field-name>interpolator</field-name>
         </requirement>
+        <requirement>
+          <role>org.apache.maven.model.normalization.Normalizer</role>
+          <role-hint>default</role-hint>
+          <field-name>normalizer</field-name>
+        </requirement>
         <requirement>
           <role>org.apache.maven.model.lifecycle.LifecycleBindingsInjector</role>
           <role-hint>default</role-hint>

maven-model-builder/src/main/java/org/apache/maven/model/normalization/DefaultNormalizer.java

@@ -0,0 +1,80 @@
+package org.apache.maven.model.normalization;
+
+/*
+ * 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.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.maven.model.Build;
+import org.apache.maven.model.Model;
+import org.apache.maven.model.Plugin;
+import org.apache.maven.model.merge.MavenModelMerger;
+import org.codehaus.plexus.component.annotations.Component;
+
+/**
+ * Handles normalization of a model.
+ * 
+ * @author Benjamin Bentmann
+ */
+@Component( role = Normalizer.class )
+public class DefaultNormalizer
+    implements Normalizer
+{
+
+    private DuplicateMerger merger = new DuplicateMerger();
+
+    public void mergeDuplicates( Model model )
+    {
+        Build build = model.getBuild();
+        if ( build != null )
+        {
+            List<Plugin> original = build.getPlugins();
+            Map<Object, Plugin> normalized = new LinkedHashMap<Object, Plugin>();
+
+            for ( Plugin plugin : original )
+            {
+                Object key = plugin.getKey();
+                Plugin first = normalized.get( key );
+                if ( first != null )
+                {
+                    merger.mergePlugin( plugin, first );
+                }
+                normalized.put( key, plugin );
+            }
+
+            build.setPlugins( new ArrayList<Plugin>( normalized.values() ) );
+        }
+    }
+
+    private static class DuplicateMerger
+        extends MavenModelMerger
+    {
+
+        public void mergePlugin( Plugin target, Plugin source )
+        {
+            super.mergePlugin( target, source, false, Collections.emptyMap() );
+        }
+
+    }
+
+}

maven-model-builder/src/main/java/org/apache/maven/model/normalization/Normalizer.java

@@ -0,0 +1,39 @@
+package org.apache.maven.model.normalization;
+
+/*
+ * 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 org.apache.maven.model.Model;
+
+/**
+ * Handles normalization of a model.
+ * 
+ * @author Benjamin Bentmann
+ */
+public interface Normalizer
+{
+
+    /**
+     * Merges duplicate elements like multiple declarations of the same build plugin in the specified model.
+     * 
+     * @param model The model whose duplicate elements should be merged, must not be <code>null</code>.
+     */
+    void mergeDuplicates( Model model );
+
+}