o Introduced model cache to avoid repeated building of models that can occur multiple times during a reactor build (e.g. parents and imported POMs)

git-svn-id: https://svn.apache.org/repos/asf/maven/components/trunk@797959 13f79535-47bb-0310-9956-ffa450edef68

maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultModelBuilder.java

@@ -424,11 +424,28 @@ public class DefaultModelBuilder
 
         if ( parent != null )
         {
-            parentData = readParentLocally( childModel, request, problems );
+            String groupId = parent.getGroupId();
+            String artifactId = parent.getArtifactId();
+            String version = parent.getVersion();
+
+            parentData = getCache( request.getModelCache(), groupId, artifactId, version, ModelCacheTag.RAW );
 
             if ( parentData == null )
             {
-                parentData = readParentExternally( childModel, request, problems );
+                parentData = readParentLocally( childModel, request, problems );
+
+                if ( parentData == null )
+                {
+                    parentData = readParentExternally( childModel, request, problems );
+                }
+
+                putCache( request.getModelCache(), groupId, artifactId, version, ModelCacheTag.RAW, parentData );
+            }
+            else
+            {
+                parentData =
+                    new ModelData( ModelUtils.cloneModel( parentData.getModel() ), parentData.getGroupId(),
+                                   parentData.getArtifactId(), parentData.getVersion() );
             }
         }
         else
@@ -497,23 +514,27 @@ public class DefaultModelBuilder
     {
         Parent parent = childModel.getParent();
 
+        String groupId = parent.getGroupId();
+        String artifactId = parent.getArtifactId();
+        String version = parent.getVersion();
+
         ModelResolver modelResolver = request.getModelResolver();
 
         if ( modelResolver == null )
         {
             throw new IllegalArgumentException( "no model resolver provided, cannot resolve parent POM "
-                + toId( parent ) + " for POM " + toSourceHint( childModel ) );
+                + toId( groupId, artifactId, version ) + " for POM " + toSourceHint( childModel ) );
         }
 
         ModelSource modelSource;
         try
         {
-            modelSource = modelResolver.resolveModel( parent.getGroupId(), parent.getArtifactId(), parent.getVersion() );
+            modelSource = modelResolver.resolveModel( groupId, artifactId, version );
         }
         catch ( UnresolvableModelException e )
         {
-            problems.add( new ModelProblem( "Non-resolvable parent POM " + toId( parent ) + " for POM "
+            problems.add( new ModelProblem( "Non-resolvable parent POM " + toId( groupId, artifactId, version )
-                + toSourceHint( childModel ) + ": " + e.getMessage(), ModelProblem.Severity.FATAL,
+                + " for POM " + toSourceHint( childModel ) + ": " + e.getMessage(), ModelProblem.Severity.FATAL,
                                             toSourceHint( childModel ), e ) );
             throw new ModelBuildingException( problems );
         }
@@ -557,60 +578,95 @@ public class DefaultModelBuilder
 
             it.remove();
 
-            if ( modelResolver == null )
+            String groupId = dependency.getGroupId();
-            {
+            String artifactId = dependency.getArtifactId();
-                throw new IllegalArgumentException( "no model resolver provided, cannot resolve import POM "
+            String version = dependency.getVersion();
-                    + toId( dependency ) + " for POM " + toSourceHint( model ) );
-            }
 
-            ModelSource importSource;
+            Model importModel =
-            try
+                getCache( request.getModelCache(), groupId, artifactId, version, ModelCacheTag.EFFECTIVE );
-            {
-                importSource =
-                    modelResolver.resolveModel( dependency.getGroupId(), dependency.getArtifactId(),
-                                                dependency.getVersion() );
-            }
-            catch ( UnresolvableModelException e )
-            {
-                problems.add( new ModelProblem( "Non-resolvable import POM " + toId( dependency ) + " for POM "
-                    + toSourceHint( model ) + ": " + e.getMessage(), ModelProblem.Severity.ERROR,
-                                                toSourceHint( model ), e ) );
-                continue;
-            }
 
-            if ( importRequest == null )
+            if ( importModel == null )
             {
-                importRequest = new DefaultModelBuildingRequest();
+                if ( modelResolver == null )
-                importRequest.setValidationLevel( ModelBuildingRequest.VALIDATION_LEVEL_MINIMAL );
+                {
+                    throw new IllegalArgumentException( "no model resolver provided, cannot resolve import POM "
+                        + toId( groupId, artifactId, version ) + " for POM " + toSourceHint( model ) );
+                }
+
+                ModelSource importSource;
+                try
+                {
+                    importSource = modelResolver.resolveModel( groupId, artifactId, version );
+                }
+                catch ( UnresolvableModelException e )
+                {
+                    problems.add( new ModelProblem( "Non-resolvable import POM " + toId( groupId, artifactId, version )
+                        + " for POM " + toSourceHint( model ) + ": " + e.getMessage(), ModelProblem.Severity.ERROR,
+                                                    toSourceHint( model ), e ) );
+                    continue;
+                }
+
+                if ( importRequest == null )
+                {
+                    importRequest = new DefaultModelBuildingRequest();
+                    importRequest.setValidationLevel( ModelBuildingRequest.VALIDATION_LEVEL_MINIMAL );
+                }
+
+                importRequest.setModelSource( importSource );
+                importRequest.setModelResolver( modelResolver.newCopy() );
+
+                ModelBuildingResult importResult;
+                try
+                {
+                    importResult = build( importRequest );
+                }
+                catch ( ModelBuildingException e )
+                {
+                    problems.addAll( e.getProblems() );
+                    continue;
+                }
+
+                problems.addAll( importResult.getProblems() );
+
+                importModel = importResult.getEffectiveModel();
+
+                putCache( request.getModelCache(), groupId, artifactId, version, ModelCacheTag.EFFECTIVE, importModel );
             }
-
+            else
-            importRequest.setModelSource( importSource );
-            importRequest.setModelResolver( modelResolver.newCopy() );
-
-            ModelBuildingResult importResult;
-            try
             {
-                importResult = build( importRequest );
+                importModel = ModelUtils.cloneModel( importModel );
             }
-            catch ( ModelBuildingException e )
-            {
-                problems.addAll( e.getProblems() );
-                continue;
-            }
-
-            problems.addAll( importResult.getProblems() );
 
             if ( importModels == null )
             {
                 importModels = new ArrayList<Model>();
             }
 
-            importModels.add( importResult.getEffectiveModel() );
+            importModels.add( importModel );
         }
 
         dependencyManagementImporter.importManagement( model, importModels, request );
     }
 
+    private <T> void putCache( ModelCache modelCache, String groupId, String artifactId, String version,
+                               ModelCacheTag<T> tag, T data )
+    {
+        if ( modelCache != null )
+        {
+            modelCache.put( groupId, artifactId, version, tag.getName(), data );
+        }
+    }
+
+    private <T> T getCache( ModelCache modelCache, String groupId, String artifactId, String version,
+                            ModelCacheTag<T> tag )
+    {
+        if ( modelCache != null )
+        {
+            return tag.getType().cast( modelCache.get( groupId, artifactId, version, tag.getName() ) );
+        }
+        return null;
+    }
+
     private void fireBuildExtensionsAssembled( Model model, ModelBuildingRequest request, List<ModelProblem> problems )
         throws ModelBuildingException
     {
@@ -669,16 +725,6 @@ public class DefaultModelBuilder
         return toId( groupId, artifactId, version );
     }
 
-    private String toId( Parent parent )
-    {
-        return toId( parent.getGroupId(), parent.getArtifactId(), parent.getVersion() );
-    }
-
-    private String toId( Dependency dependency )
-    {
-        return toId( dependency.getGroupId(), dependency.getArtifactId(), dependency.getVersion() );
-    }
-
     private String toId( String groupId, String artifactId, String version )
     {
         StringBuilder buffer = new StringBuilder( 96 );

maven-model-builder/src/main/java/org/apache/maven/model/building/DefaultModelBuildingRequest.java

@@ -61,6 +61,8 @@ public class DefaultModelBuildingRequest
 
     private List<ModelBuildingListener> modelBuildingListeners;
 
+    private ModelCache modelCache;
+
     public File getPomFile()
     {
         return pomFile;
@@ -279,4 +281,16 @@ public class DefaultModelBuildingRequest
         return this;
     }
 
+    public ModelCache getModelCache()
+    {
+        return this.modelCache;
+    }
+
+    public DefaultModelBuildingRequest setModelCache( ModelCache modelCache )
+    {
+        this.modelCache = modelCache;
+
+        return this;
+    }
+
 }

maven-model-builder/src/main/java/org/apache/maven/model/building/ModelBuildingRequest.java

@@ -262,4 +262,20 @@ public interface ModelBuildingRequest
      */
     ModelBuildingRequest setModelBuildingListeners( List<? extends ModelBuildingListener> modelBuildingListeners );
 
+    /**
+     * Gets the model cache to use for reuse of previously built models.
+     * 
+     * @return The model cache or {@code null} if not set.
+     */
+    ModelCache getModelCache();
+
+    /**
+     * Sets the model cache to use for reuse of previously built models. This is an optional component that serves
+     * performance optimizations.
+     * 
+     * @param modelCache The model cache to use, may be {@code null}.
+     * @return This request, never {@code null}.
+     */
+    ModelBuildingRequest setModelCache( ModelCache modelCache );
+
 }

maven-model-builder/src/main/java/org/apache/maven/model/building/ModelCache.java

@@ -0,0 +1,56 @@
+package org.apache.maven.model.building;
+
+/*
+ * 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.
+ */
+
+/**
+ * Caches auxiliary data used during model building like already processed raw/effective models. The data in the cache
+ * is meant for exclusive consumption by the model builder and is opaque to the cache implementation. The cache key is
+ * formed by a combination of group id, artifact id, version and tag. The first three components generally refer to the
+ * identify of a model. The tag allows for further classification of the associated data on the sole discretion of the
+ * model builder.
+ * 
+ * @author Benjamin Bentmann
+ */
+public interface ModelCache
+{
+
+    /**
+     * Puts the specified data into the cache.
+     * 
+     * @param groupId The group id of the cache record, must not be {@code null}.
+     * @param artifactId The artifact id of the cache record, must not be {@code null}.
+     * @param version The version of the cache record, must not be {@code null}.
+     * @param tag The tag of the cache record, must not be {@code null}.
+     * @param data The data to store in the cache, must not be {@code null}.
+     */
+    void put( String groupId, String artifactId, String version, String tag, Object data );
+
+    /**
+     * Gets the specified data from the cache.
+     * 
+     * @param groupId The group id of the cache record, must not be {@code null}.
+     * @param artifactId The artifact id of the cache record, must not be {@code null}.
+     * @param version The version of the cache record, must not be {@code null}.
+     * @param tag The tag of the cache record, must not be {@code null}.
+     * @return The requested data or {@code null} if none was present in the cache.
+     */
+    Object get( String groupId, String artifactId, String version, String tag );
+
+}

maven-model-builder/src/main/java/org/apache/maven/model/building/ModelCacheTag.java

@@ -0,0 +1,84 @@
+package org.apache.maven.model.building;
+
+/*
+ * 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;
+
+/**
+ * Describes a tag used by the model builder to access a {@link ModelCache}. This interface simply aggregates a name and
+ * a class to provide some type safety when working with the otherwise untyped cache.
+ * 
+ * @author Benjamin Bentmann
+ * @param <T> The type of data associated with the tag.
+ */
+interface ModelCacheTag<T>
+{
+
+    /**
+     * Gets the name of the tag.
+     * 
+     * @return The name of the tag, must not be {@code null}.
+     */
+    String getName();
+
+    /**
+     * Gets the type of data associated with this tag.
+     * 
+     * @return The type of data, must not be {@code null}.
+     */
+    Class<T> getType();
+
+    /**
+     * The tag used to denote raw model data.
+     */
+    public static final ModelCacheTag<ModelData> RAW = new ModelCacheTag<ModelData>()
+    {
+
+        public String getName()
+        {
+            return "raw";
+        }
+
+        public Class<ModelData> getType()
+        {
+            return ModelData.class;
+        }
+
+    };
+
+    /**
+     * The tag used to denote an effective model.
+     */
+    public static final ModelCacheTag<Model> EFFECTIVE = new ModelCacheTag<Model>()
+    {
+
+        public String getName()
+        {
+            return "effective";
+        }
+
+        public Class<Model> getType()
+        {
+            return Model.class;
+        }
+
+    };
+
+}