text: /**
   * 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.apache.apex.malhar.contrib.util;
  
  import java.lang.reflect.Constructor;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * This is a copy from contrib, should be merged later.
   *
   */
  public class TupleGenerator<T>
  {
    private static final Logger logger = LoggerFactory.getLogger( TupleGenerator.class );
  
    private volatile long rowId = 0;
    private Constructor<T> constructor;
  
    private static Class<?>[] paramTypes = new Class<?>[]{Long.class, long.class, Integer.class, int.class };
  
    public TupleGenerator()
    {
    }
  
    public TupleGenerator( Class<T> tupleClass )
    {
      useTupleClass( tupleClass );
    }
  
    public void useTupleClass( Class<T> tupleClass )
    {
      for ( Class<?> paramType : paramTypes ) {
        constructor = tryGetConstructor( tupleClass, paramType );
        if ( constructor != null ) {
          break;
        }
      }
      if ( constructor == null ) {
        logger.error( "Not found proper constructor." );
        throw new RuntimeException( "Not found proper constructor." );
      }
    }
  
    protected Constructor<T> tryGetConstructor( Class<T> tupleClass, Class<?> parameterType )
    {
      try {
        return tupleClass.getConstructor( parameterType );
      } catch ( Exception e ) {
        return null;
      }
    }
  
    public void reset()
    {
      rowId = 0;
    }
  
    public T getNextTuple()
    {
      if ( constructor == null ) {
        throw new RuntimeException( "Not found proper constructor." );
      }
      long curRowId = ++rowId;
      try {
        return constructor.newInstance( curRowId );
      } catch ( Exception e) {
        logger.error( "newInstance failed.", e );
        return null;
      }
    }
  
  }
  