Merge pull request #8 from tporadowski/entityfactory-gson-config

EntityFactory allows fine-tuning of Gson

Author: gschwab

src/main/java/com/arangodb/entity/EntityFactory.java

@@ -40,7 +40,7 @@ public class EntityFactory {
   private static Gson gson;
   private static Gson gsonNull;
 
-  private static GsonBuilder getBuilder() {
+  public static GsonBuilder getGsonBuilder() {
     return new GsonBuilder()
       .addSerializationExclusionStrategy(new ExcludeExclusionStrategy(true))
       .addDeserializationExclusionStrategy(new ExcludeExclusionStrategy(false))
@@ -101,10 +101,32 @@ private static GsonBuilder getBuilder() {
   }
 
   static {
-    gson = getBuilder().create();
-    gsonNull = getBuilder().serializeNulls().create();
+	  configure(getGsonBuilder());
   }
 
+  /**
+   * Configures instances of Gson used by this factory.
+   * 
+   * @param builders one or two GsonBuilder instances. If only one is provided it will be used for
+   *        initializing both <code>gson</code> and <code>gsonNull</code> fields (latter with
+   *        <code>serializeNulls()</code> called prior to creating). If two are given - first initializes <code>gson</code>
+   *        field, second initializes <code>gsonNull</code> (used when serialization of nulls is requested).
+   */
+  public static void configure(GsonBuilder ...builders) {
+	  if (builders.length < 1) {
+		  throw new IllegalArgumentException("builders");
+	  }
+
+	  gson = builders[0].create();
+	  
+	  if (builders.length > 1) {
+		  gsonNull = builders[1].create();
+	  } else {
+		  //use the first one again, but with nulls serialization turned on
+		  gsonNull = builders[0].serializeNulls().create();
+	  }
+  }
+  
   public static <T> T createEntity(String jsonText, Type type) {
     return gson.fromJson(jsonText, type);
   }

src/test/java/com/arangodb/ArangoDriverDocumentTest.java

@@ -36,6 +36,7 @@
 
 import com.arangodb.entity.CollectionEntity;
 import com.arangodb.entity.DocumentEntity;
+import com.arangodb.entity.EntityFactory;
 
 /**
  * @author tamtam180 - kirscheless at gmail.com
@@ -54,7 +55,8 @@ public ArangoDriverDocumentTest(ArangoConfigure configure, ArangoDriver driver)
 
   CollectionEntity col1;
   CollectionEntity col2;
-
+  TestInterfaceInstanceCreator testInstanceCreator;
+  
   @Before
   public void before() throws ArangoException {
 
@@ -72,12 +74,18 @@ public void before() throws ArangoException {
     col1 = driver.createCollection(collectionName);
     col2 = driver.createCollection(collectionName2);
 
+    //configure Gson to use our instance creator whenever documents of TestInterface are requested
+    testInstanceCreator = new TestInterfaceInstanceCreator();
+	EntityFactory.configure(EntityFactory.getGsonBuilder().registerTypeAdapter(TestInterface.class, testInstanceCreator));
+
     logger.debug("--");
 
   }
 
   @After
   public void after() {
+	//revert to default configuration
+	EntityFactory.configure(EntityFactory.getGsonBuilder());
     logger.debug("----------");
   }
 
@@ -320,7 +328,27 @@ public void test_get_document() throws ArangoException {
     assertThat(retVal.getEntity().getDesc(), is("説明:9999"));
     assertThat(retVal.getEntity().getAge(), is(9999));
   }
+ 
+  @Test
+  public void test_get_document_with_instance_creator() throws ArangoException {
+	//save an instance of TestInterfaceImpl with null as "name"
+	DocumentEntity<TestInterfaceImpl> doc = driver.createDocument(collectionName, new TestInterfaceImpl(null), null, false);
+
+	assertThat(doc.getDocumentKey(), is(notNullValue()));
+	assertThat(doc.getDocumentHandle(), is(collectionName + "/" + doc.getDocumentKey()));
+	assertThat(doc.getDocumentRevision(), is(not(0L)));
 
+	//now we should get back an instance created with our configured InstanceCreator<TestInterface> (with "name" already set)
+	DocumentEntity<TestInterface> retVal = driver.getDocument(doc.getDocumentHandle(), TestInterface.class);
+    assertThat(retVal.getDocumentHandle(), is(doc.getDocumentHandle()));
+    assertThat(retVal.getDocumentRevision(), is(doc.getDocumentRevision()));
+    assertThat(retVal.getDocumentKey(), is(doc.getDocumentKey()));
+    assertThat(retVal.getEntity(), instanceOf(TestInterface.class));
+    assertThat(retVal.getEntity(), instanceOf(TestInterfaceImpl.class));
+	assertThat(testInstanceCreator.getCounter(), is(1));
+    assertThat(retVal.getEntity().getName(), is("name 0"));
+  }
+  
   @Test
   public void test_get_document_collection_not_found() throws ArangoException {
     // Get

src/test/java/com/arangodb/TestInterface.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2015 tporadowski
+ *
+ * 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.
+ */
+
+package com.arangodb;
+
+/**
+ * @author tporadowski - tomasz at poradowski.com
+ */
+public interface TestInterface {
+	String getName();
+}

src/test/java/com/arangodb/TestInterfaceImpl.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2015 tporadowski
+ *
+ * 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.
+ */
+
+package com.arangodb;
+
+/**
+ * @author tporadowski - tomasz at poradowski.com
+ */
+public class TestInterfaceImpl implements TestInterface {
+	private String name;
+	
+	public TestInterfaceImpl(String name) {
+		this.name = name;
+	}
+	
+	@Override
+	public String getName() {
+		return name;
+	}
+
+}

src/test/java/com/arangodb/TestInterfaceInstanceCreator.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2015 tporadowski
+ *
+ * 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.
+ */
+
+package com.arangodb;
+
+import java.lang.reflect.Type;
+
+import com.google.gson.InstanceCreator;
+
+/**
+ * @author tporadowski - tomasz at poradowski.com
+ */
+public class TestInterfaceInstanceCreator implements
+		InstanceCreator<TestInterface> {
+
+	private int counter;
+	
+	@Override
+	public TestInterface createInstance(Type type) {
+		return new TestInterfaceImpl("name " + counter++);
+	}
+
+	/**
+	 * @return the counter
+	 */
+	public int getCounter() {
+		return counter;
+	}
+}