RecordAccessorProviderFactory.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 gobblin.recordaccess;

import java.util.ServiceLoader;


/**
 * This object can build RecordAccessors for a given object type. Developers who wish to
 * provide custom RecordAccessors can do so by implementing the RecordAccessProvider interface
 * and ensuring that their JAR has a META-INF/services/ entry pointing the ServiceLoader to
 * the custom implementation.
 */
public class RecordAccessorProviderFactory {
  private static ServiceLoader<RecordAccessorProvider> recordAccessorProviders =
      ServiceLoader.load(RecordAccessorProvider.class);

  /**
   * Get a RecordAccessor for a given object. Throws IllegalArgumentException if none
   * can be built.
   */
  public synchronized static RecordAccessor getRecordAccessorForObject(Object obj) {
    for (RecordAccessorProvider p: recordAccessorProviders) {
      RecordAccessor accessor = p.recordAccessorForObject(obj);
      if (accessor != null) {
        return accessor;
      }
    }

    throw new IllegalArgumentException("Can't build accessor for object " + obj.toString() + "!");
  }
}