AnnotatedRebindingJpaModule.java

/**
 * Copyright 2010 CosmoCode GmbH
 *
 * 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 de.cosmocode.palava.jpa;

import java.lang.annotation.Annotation;
import java.util.Properties;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

import com.google.common.base.Preconditions;
import com.google.inject.Key;
import com.google.inject.Singleton;
import com.google.inject.name.Names;

import de.cosmocode.palava.core.inject.AbstractRebindModule;
import de.cosmocode.palava.core.inject.Config;
import de.cosmocode.palava.scope.UnitOfWork;

/**
 * A variation of the {@link JpaModule} which allows binding using an annotation.
 *
 * @since 3.2
 * @author Willi Schoenborn
 */
public final class AnnotatedRebindingJpaModule extends AbstractRebindModule {

    private final Class<? extends Annotation> annotation;
    private final Config config;
    
    public AnnotatedRebindingJpaModule(Class<? extends Annotation> annotation, String prefix) {
        this.annotation = Preconditions.checkNotNull(annotation, "Annotation");
        this.config = new Config(prefix);
    }

    @Override
    protected void configuration() {
        bind(String.class).annotatedWith(Names.named(PersistenceConfig.UNIT_NAME)).to(
            Key.get(String.class, Names.named(config.prefixed(PersistenceConfig.UNIT_NAME))));
    }

    @Override
    protected void optionals() {
        bind(Properties.class).annotatedWith(Names.named(PersistenceConfig.PROPERTIES)).to(
            Key.get(Properties.class, Names.named(config.prefixed(PersistenceConfig.PROPERTIES))));
    }

    @Override
    protected void bindings() {
        bind(PersistenceService.class).annotatedWith(annotation).
            to(DefaultPersistenceService.class).in(Singleton.class);
        bind(EntityManagerFactory.class).annotatedWith(annotation).
            to(Key.get(PersistenceService.class, annotation)).in(Singleton.class);
        bind(EntityManager.class).annotatedWith(annotation).
            toProvider(Key.get(PersistenceService.class, annotation)).in(UnitOfWork.class);
    }

    @Override
    protected void expose() {
        expose(PersistenceService.class).annotatedWith(annotation);
        expose(EntityManagerFactory.class).annotatedWith(annotation);
        expose(EntityManager.class).annotatedWith(annotation);
    }

}