package org.springframework.batch.integration.chunk;
   
   import java.util.ArrayList;
   import java.util.List;
   
   import org.apache.commons.logging.Log;
   import org.apache.commons.logging.LogFactory;
   import org.springframework.batch.item.ItemReader;
   import org.springframework.batch.item.ParseException;
  import org.springframework.batch.item.UnexpectedInputException;
  import org.springframework.stereotype.Component;
  
  @Component
  public class TestItemReader<T> implements ItemReader<T> {
  
  	private static final Log logger = LogFactory.getLog(TestItemReader.class);
  
  	/**
  	 * Counts the number of chunks processed in the handler.
  	 */
  	public volatile int count = 0;
  
  	/**
  	 * Item that causes failure in handler.
  	 */
  	public final static String FAIL_ON = "bad";
  
  	/**
  	 * Item that causes handler to wait to simulate delayed processing.
  	 */
  	public static final String WAIT_ON = "wait";
  
  	private List<T> items = new ArrayList<T>();
  	
  	/**
  	 * @param items the items to set
  	 */
  	public void setItems(List<T> items) {
  		this.items = items;
  	}
  
  	public T read() throws Exception, UnexpectedInputException, ParseException {
  
  		if (count>=items.size()) {
  			return null;
  		}
  
  		T item = items.get(count++);
  
  		logger.debug("Reading "+item);
  
  		if (item.equals(WAIT_ON)) {
  			try {
  				Thread.sleep(200);
  			}
  			catch (InterruptedException e) {
  				Thread.currentThread().interrupt();
  				throw new RuntimeException("Unexpected interruption.", e);
  			}
  		}
  
  		if (item.equals(FAIL_ON)) {
  			throw new IllegalStateException("Planned failure on: " + FAIL_ON);
  		}
  		
  		return item;
  
  	}
  
  }