#365 Making Services factory agnostic of specific services

processor/src/main/java/org/mapstruct/ap/model/assignment/SetterWrapperForCollectionsAndMaps.java

@@ -20,12 +20,10 @@ package org.mapstruct.ap.model.assignment;
 
 import java.util.HashSet;
 import java.util.Set;
-
 import javax.lang.model.element.ExecutableElement;
 
 import org.mapstruct.ap.model.common.Type;
-import org.mapstruct.ap.services.Services;
-import org.mapstruct.ap.spi.AccessorNamingStrategy;
+import org.mapstruct.ap.util.Executables;
 
 /**
  * This wrapper handles the situation were an assignment is done via the setter.
@@ -45,15 +43,11 @@ public class SetterWrapperForCollectionsAndMaps extends AssignmentWrapper {
     private final Assignment newCollectionOrMapAssignment;
 
     public SetterWrapperForCollectionsAndMaps(Assignment decoratedAssignment,
-                                        ExecutableElement targetSetter,
-                                        Assignment newCollectionOrMapAssignment) {
+                                              ExecutableElement targetSetter,
+                                              Assignment newCollectionOrMapAssignment) {
         super( decoratedAssignment );
 
-        AccessorNamingStrategy accessorNamingStrategy = Services.getAccessorNamingStrategy();
-
-        this.targetGetterName = accessorNamingStrategy.getCollectionGetterName(
-                accessorNamingStrategy.getPropertyName( targetSetter )
-        );
+        this.targetGetterName = Executables.getCollectionGetterName( targetSetter );
         this.newCollectionOrMapAssignment = newCollectionOrMapAssignment;
     }
 

processor/src/main/java/org/mapstruct/ap/naming/DefaultAccessorNamingStrategy.java

@@ -16,10 +16,9 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.mapstruct.ap.services;
+package org.mapstruct.ap.naming;
 
 import java.beans.Introspector;
-
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.type.DeclaredType;
@@ -36,7 +35,7 @@ import org.mapstruct.ap.spi.MethodType;
  *
  * @author Christian Schuster
  */
-class DefaultAccessorNamingStrategy implements AccessorNamingStrategy {
+public class DefaultAccessorNamingStrategy implements AccessorNamingStrategy {
 
     @Override
     public MethodType getMethodType(ExecutableElement method) {

processor/src/main/java/org/mapstruct/ap/naming/package-info.java

@@ -0,0 +1,24 @@
+/**
+ *  Copyright 2012-2015 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  Licensed 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.
+ */
+/**
+ * <p>
+ * SPI (service provider interface) contracts to be implemented for advanced use cases.
+ * </p>
+ */
+package org.mapstruct.ap.naming;

processor/src/main/java/org/mapstruct/ap/services/Services.java

@@ -19,8 +19,8 @@
 package org.mapstruct.ap.services;
 
 import java.util.ServiceLoader;
-
-import org.mapstruct.ap.spi.AccessorNamingStrategy;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * A simple locator for SPI implementations.
@@ -29,32 +29,35 @@ import org.mapstruct.ap.spi.AccessorNamingStrategy;
  */
 public class Services {
 
-    private static final AccessorNamingStrategy ACCESSOR_NAMING_STRATEGY = findAccessorNamingStrategy();
+    private static final ConcurrentMap<Class<?>, Object> SERVICES = new ConcurrentHashMap<Class<?>, Object>();
 
     private Services() {
     }
 
-    /**
-     * Obtain an implementation of {@link AccessorNamingStrategy}. If no specialized implementation is found using
-     * {@link ServiceLoader}, a JavaBeans-compliant default implementation is returned. The result is cached across
-     * invocations.
-     *
-     * @return The implementation of {@link AccessorNamingStrategy}.
-     * @throws IllegalStateException If more than one implementation is found by
-     *             {@link ServiceLoader#load(Class, ClassLoader)}.
-     */
-    public static AccessorNamingStrategy getAccessorNamingStrategy() {
-        return ACCESSOR_NAMING_STRATEGY;
-    }
+    public static <T> T get(Class<T> serviceType, T defaultValue) {
+        @SuppressWarnings("unchecked")
+        T service = (T) SERVICES.get( serviceType );
 
-    private static AccessorNamingStrategy findAccessorNamingStrategy() {
-        AccessorNamingStrategy defaultImpl = new DefaultAccessorNamingStrategy();
-        AccessorNamingStrategy impl = find( AccessorNamingStrategy.class );
-        if ( impl == null ) {
-            impl = defaultImpl;
+        if ( service == null ) {
+            service = loadAndCache( serviceType, defaultValue );
         }
 
-        return impl;
+        return service;
+    }
+
+    private static <T> T loadAndCache(Class<T> serviceType, T defaultValue) {
+        T service = find( serviceType );
+        if ( service == null ) {
+            service = defaultValue;
+        }
+
+        @SuppressWarnings("unchecked")
+        T cached = (T) SERVICES.putIfAbsent( serviceType, service );
+        if ( cached != null ) {
+            service = (T) cached;
+        }
+
+        return service;
     }
 
     private static <T> T find(Class<T> spi) {
@@ -68,7 +71,8 @@ public class Services {
                 throw new IllegalStateException(
                     "Multiple implementations have been found for the service provider interface "
                         + spi.getCanonicalName() + ": " + matchingImplementation.getClass().getCanonicalName() + ", "
-                        + implementation.getClass().getCanonicalName() + "." );
+                        + implementation.getClass().getCanonicalName() + "."
+                );
             }
         }
 

processor/src/main/java/org/mapstruct/ap/util/Executables.java

@@ -20,7 +20,6 @@ package org.mapstruct.ap.util;
 
 import java.util.ArrayList;
 import java.util.List;
-
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.TypeElement;
@@ -29,6 +28,7 @@ import javax.lang.model.type.TypeKind;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.util.Elements;
 
+import org.mapstruct.ap.naming.DefaultAccessorNamingStrategy;
 import org.mapstruct.ap.services.Services;
 import org.mapstruct.ap.spi.AccessorNamingStrategy;
 import org.mapstruct.ap.spi.MethodType;
@@ -43,7 +43,10 @@ import static org.mapstruct.ap.util.SpecificCompilerWorkarounds.replaceTypeEleme
  */
 public class Executables {
 
-    private static AccessorNamingStrategy accessorNamingStrategy = Services.getAccessorNamingStrategy();
+    private static AccessorNamingStrategy accessorNamingStrategy = Services.get(
+        AccessorNamingStrategy.class,
+        new DefaultAccessorNamingStrategy()
+    );
 
     private Executables() {
     }
@@ -51,7 +54,7 @@ public class Executables {
     public static boolean isGetterMethod(ExecutableElement method) {
         return isPublic( method ) &&
             method.getParameters().isEmpty() &&
-            Services.getAccessorNamingStrategy().getMethodType( method ) == MethodType.GETTER;
+            accessorNamingStrategy.getMethodType( method ) == MethodType.GETTER;
     }
 
     public static boolean isSetterMethod(ExecutableElement method) {
@@ -83,6 +86,11 @@ public class Executables {
         return accessorNamingStrategy.getElementName( adderMethod );
     }
 
+    public static String getCollectionGetterName(ExecutableElement targetSetter) {
+        String propertyName = accessorNamingStrategy.getPropertyName( targetSetter );
+        return accessorNamingStrategy.getCollectionGetterName( propertyName );
+    }
+
     /**
      * @param mirror the type mirror
      *