AbstractBatchDataUpgrade.java

package fr.openwide.core.jpa.more.business.upgrade.model;

import java.util.List;

import com.google.common.collect.Lists;

import fr.openwide.core.jpa.exception.SecurityServiceException;
import fr.openwide.core.jpa.exception.ServiceException;

public abstract class AbstractBatchDataUpgrade<T> implements IDataUpgrade {
	
	private static final int DEFAULT_BATCH_SIZE = 100;
	
	private int batchSize;
	
	protected AbstractBatchDataUpgrade() {
		this(DEFAULT_BATCH_SIZE);
	}
	
	protected AbstractBatchDataUpgrade(int batchSize) {
		this.batchSize = batchSize;
	}

	@Override
	public void perform() throws ServiceException, SecurityServiceException {
		List<T> allIds = listIds();
		List<List<T>> batches = Lists.partition(allIds, batchSize);
		
		for (List<T> batch : batches) {
			handleBatch(batch);
			batchEnd();
		}
	}
	
	protected abstract List<T> listIds();
	
	protected abstract void handleBatch(List<T> batchIds) throws ServiceException, SecurityServiceException;
	
	protected abstract void batchEnd();

}