PersistenceMemberProvider.java

/**
 *
 * 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.
 */

package org.guiceyfruit.jpa.support;

import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.TypeLiteral;
import java.lang.annotation.Annotation;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.Map;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.guiceyfruit.support.AnnotationMemberProviderSupport;

/**
 * Allows the JPA persistence context to be injected via {@link javax.persistence.PersistenceContext}
 *
 * @version $Revision: 1.1 $
 */
public class PersistenceMemberProvider extends AnnotationMemberProviderSupport<PersistenceContext> {

  private final Provider<EntityManager> defaultEntityManager;

  private Map<String, Provider<EntityManager>> namedEntityManagers;

  @Inject
  public PersistenceMemberProvider(Provider<EntityManager> defaultEntityManager) {
    this.defaultEntityManager = defaultEntityManager;
  }

  protected Object provide(PersistenceContext annotation, Member member,
      TypeLiteral<?> requiredType, Class<?> memberType, Annotation[] annotations) {

    Provider<EntityManager> provider = null;

    String name = annotation.name();
    if (namedEntityManagers != null && name != null && name.length() > 0) {
      provider = namedEntityManagers.get(name);
    }
    if (provider == null) {
      provider = defaultEntityManager;
    }
    return provider.get();
  }

  public boolean isNullParameterAllowed(PersistenceContext annotation, Method method,
      Class<?> parameterType, int parameterIndex) {
    return false;
  }

  public Map<String, Provider<EntityManager>> getNamedEntityManagers() {
    return namedEntityManagers;
  }

  @Inject(optional = true)
  public void setNamedEntityManagers(Map<String, Provider<EntityManager>> namedEntityManagers) {
    this.namedEntityManagers = namedEntityManagers;
  }
}