<name>/support/general</name>
<url>http://wamblee.org</url>
<dependencies>
+ <dependency>
+ <groupId>javax.persistence</groupId>
+ <artifactId>persistence-api</artifactId>
+ <scope>provided</scope>
+ </dependency>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
+ <scope>provided</scope>
</dependency>
<dependency>
<groupId>oro</groupId>
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.persistence;
+
+/**
+ * Detachable implementation that takes care of the basic logic for detachable
+ * objects. All that needs to be done is to implement {@link #load()}.
+ *
+ * @param <T>
+ * The type of the object to be attached/detached
+ * @param <Ref>
+ * The type of the reference to store when the object is detached.
+ */
+public abstract class AbstractDetachable<T, Ref> implements Detachable<T> {
+
+ private T object;
+ private Ref reference;
+
+ /**
+ * Constructs the detachable.
+ *
+ * @param aObject
+ * Object.
+ * @throws IllegalArgumentException
+ * When the object passed in is null.
+ */
+ protected AbstractDetachable(T aObject) {
+ if (aObject == null) {
+ throw new IllegalArgumentException("Object '" + aObject +
+ "' is null");
+ }
+ object = aObject;
+ reference = null;
+ }
+
+ /*
+ * (non-Javadoc)
+ *
+ * @see org.wamblee.persistence.Detachable#detach()
+ */
+ public void detach() {
+ if (object == null) {
+ return; // Nothing to do.
+ }
+ reference = getReference(object);
+ if (reference == null) {
+ throw new IllegalStateException("Object '" + object +
+ "' not persisted yet'");
+ }
+ object = null;
+ }
+
+ /*
+ * (non-Javadoc)
+ *
+ * @see org.wamblee.persistence.Detachable#get()
+ */
+ public T get() {
+ if (object == null) {
+ object = load(reference);
+ reference = null;
+ }
+ return object;
+ }
+
+ /**
+ * For testing.
+ *
+ * @return current object.
+ */
+ T getObject() {
+ return object;
+ }
+
+ /**
+ * For testing.
+ *
+ * @return The reference.
+ */
+ Ref getReference() {
+ return reference;
+ }
+
+ /**
+ * Loads the object based on a reference.
+ *
+ * @param aReference
+ * Reference.
+ * @return Object (may be null ).
+ */
+ protected abstract T load(Ref aReference);
+
+ /**
+ * Obtains the reference for a given object.
+ *
+ * @param aObject
+ * Object.
+ * @return Reference.
+ */
+ protected abstract Ref getReference(T aObject);
+
+}
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.persistence;
+
+import java.io.Serializable;
+
+/**
+ * Represents a detachable object. It represent a reference to a persistent object.
+ * The object is detachable in that the memory footprint can be reduced by not keeping
+ * a reference to the complete java object, but only to its identify in persistent
+ * storage. This is typically the primary key in a relational database.
+ */
+public interface Detachable<T> extends Serializable {
+
+ /**
+ * Detaches the object.
+ */
+ void detach();
+
+ /**
+ * Gets the object, attaching it if needed.
+ * @return
+ */
+ T get();
+
+}
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.persistence;
+
+/**
+ * Inmemory detachable that simply returns the object passed in. Typiocally used for testing.
+ * It does nothing at detach.
+ *
+ * @param <T>
+ * Type of the detachable.
+ */
+public class InMemoryDetachable<T> implements Detachable<T> {
+
+ private T object;
+
+ /**
+ * Constructs the detachable.
+ * @param aObject
+ */
+ public InMemoryDetachable(T aObject) {
+ object = aObject;
+ }
+
+ /*
+ * (non-Javadoc)
+ * @see org.wamblee.persistence.Detachable#detach()
+ */
+ public void detach() {
+ // No op.
+ }
+
+ /*
+ * (non-Javadoc)
+ * @see org.wamblee.persistence.Detachable#get()
+ */
+ public T get() {
+ return object;
+ }
+
+}
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.persistence;
+
+import java.io.Serializable;
+
+import javax.persistence.EntityManager;
+
+/**
+ * Detachable JPA entity.
+ *
+ * @author Erik Brakkee
+ *
+ * @param <T> Entity type.
+ */
+public class JpaDetachable<T> extends AbstractDetachable<T, Serializable> {
+
+ private EntityManager entityManager;
+ private Class<T> entityType;
+
+ /**
+ * Constructs the detachable.
+ * @param aEntity Entity.
+ */
+ public JpaDetachable(EntityManager aEntityManager, T aEntity) {
+ super(aEntity);
+ entityManager = aEntityManager;
+ entityType = (Class<T>)aEntity.getClass();
+ }
+
+ /*
+ * (non-Javadoc)
+ * @see org.wamblee.persistence.AbstractDetachable#getReference(java.lang.Object)
+ */
+ protected Serializable getReference(T aObject) {
+ Persistent persistent = PersistentFactory.create(aObject);
+ return persistent.getPrimaryKey();
+ }
+
+ @Override
+ protected T load(Serializable aReference) {
+ return entityManager.find(entityType, aReference);
+ }
+}
List<Accessor> pkAccessors = AnnotationUtils.analyse(aClass, Id.class);
List<Accessor> versionAccessors = AnnotationUtils.analyse(aClass,
Version.class);
- Accessor<Serializable> pk = null;
- if ( pkAccessors.size() > 0 ) {
+ Accessor<Serializable> pk = null;
+ if (pkAccessors.size() > 0) {
pk = pkAccessors.get(0);
}
- Accessor<Integer> version = null;
- if ( versionAccessors.size() > 0 ) {
+ Accessor<Integer> version = null;
+ if (versionAccessors.size() > 0) {
version = versionAccessors.get(0);
}
- if (pk != null|| version != null) {
+ if (pk != null || version != null) {
return new EntityAccessor(pk, version);
}
return null;
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.persistence;
+
+import static org.mockito.Mockito.*;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.TestCase.*;
+
+public class AbstractDetachableTest {
+
+ public static class X {
+
+ }
+
+ public static interface DetachableMethods {
+ Integer getReference(X aObject);
+
+ X load(Integer aReference);
+ }
+
+ public class MyDetachable extends AbstractDetachable<X, Integer> {
+
+ public MyDetachable(X aObj) {
+ super(aObj);
+ }
+
+ @Override
+ protected Integer getReference(X aObject) {
+ return methods.getReference(aObject);
+ }
+
+ @Override
+ protected X load(Integer aReference) {
+ return methods.load(aReference);
+ }
+
+ }
+
+ private DetachableMethods methods;
+ private AbstractDetachable<X, Integer> detachable;
+ private X x;
+
+ @Before
+ public void setUp() {
+ methods = mock(DetachableMethods.class);
+ }
+
+ @Test(expected = IllegalArgumentException.class)
+ public void testNullPassedIn() {
+ detachable = new MyDetachable(null);
+ }
+
+ @Test
+ public void testDetach() {
+ x = new X();
+ Integer ref = 100;
+ when(methods.getReference(any(X.class))).thenReturn(ref);
+ detachable = new MyDetachable(x);
+ verifyNoMoreInteractions(methods);
+ detachable.detach();
+ verify(methods).getReference(same(x));
+ assertNull(detachable.getObject());
+ assertEquals(ref, detachable.getReference());
+ }
+
+ @Test
+ public void testDetachTwice() {
+ reset(methods);
+ testDetach();
+ detachable.detach();
+ detachable.detach();
+ verifyNoMoreInteractions(methods);
+ }
+
+ @Test(expected = IllegalStateException.class)
+ public void testDetachWithNullReference() {
+ x = new X();
+ Integer ref = 100;
+ when(methods.getReference(any(X.class))).thenReturn(null);
+ detachable = new MyDetachable(x);
+ verifyNoMoreInteractions(methods);
+ detachable.detach();
+ }
+
+ @Test
+ public void testReattach() {
+ testDetach();
+ reset(methods);
+
+ X x2 = new X(); // the new X loaded from persistent storage.
+ when(methods.load(detachable.getReference())).thenReturn(x2);
+
+ X x3 = detachable.get();
+ verify(methods).load(100);
+ assertSame(x2, x3);
+
+ assertSame(x2, detachable.getObject());
+ }
+
+ @Test
+ public void testGetInvokedTwiceNoLoads() {
+ testReattach();
+ reset(methods);
+ detachable.get();
+ detachable.get();
+ verifyNoMoreInteractions(methods);
+ }
+
+
+}
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.persistence;
+
+import static junit.framework.Assert.*;
+
+import org.junit.Test;
+
+public class InMemoryDetachableTest {
+
+ public static class X {
+
+ }
+
+ @Test
+ public void testXxx() {
+ X x = new X();
+ InMemoryDetachable<X> detachable = new InMemoryDetachable<X>(x);
+ assertSame(x, detachable.get());
+ }
+}
--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.persistence;
+
+import static org.mockito.Mockito.*;
+
+import javax.persistence.EntityManager;
+import javax.persistence.Id;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.TestCase.*;
+
+public class JpaDetachableTest {
+
+ public class X {
+ @Id
+ private int id;
+
+ }
+
+ private EntityManager em;
+
+ @Before
+ public void setUp() {
+ em = mock(EntityManager.class);
+ }
+
+ @Test
+ public void testDetachAttach() {
+ X x = new X();
+ x.id = 100;
+
+ JpaDetachable<X> d = new JpaDetachable<X>(em, x);
+ assertNull(d.getReference());
+ d.detach();
+ assertEquals(100, d.getReference());
+
+ X x2 = new X();
+ x2.id = 100;
+ when(em.find(X.class, 100)).thenReturn(x2);
+ X x3 = d.get();
+ assertSame(x2, x3);
+ verify(em).find(X.class, 100);
+
+ }
+}
git://wamblee.org / utils / commitdiff