info.archinnov.achilles.iterator.CQLSliceQueryIterator Maven / Gradle / Ivy

/**
 *
 * Copyright (C) 2012-2013 DuyHai DOAN
 *
 * Licensed 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 info.archinnov.achilles.iterator;

import info.archinnov.achilles.context.CQLPersistenceContext;
import info.archinnov.achilles.entity.CQLEntityMapper;
import info.archinnov.achilles.entity.metadata.EntityMeta;
import info.archinnov.achilles.entity.operations.CQLEntityProxifier;
import info.archinnov.achilles.proxy.CQLRowMethodInvoker;
import info.archinnov.achilles.query.slice.CQLSliceQuery;

import java.util.Iterator;

import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.Row;

public class CQLSliceQueryIterator implements Iterator {

	private CQLPersistenceContext context;
	private Iterator iterator;
	private String varyingComponentName;
	private Object lastVaryingComponentValue;
	private Class varyingComponentClass;
	private PreparedStatement ps;
	private EntityMeta meta;
	private int batchSize;
	private int count = 0;

	private CQLEntityMapper mapper = new CQLEntityMapper();
	private CQLRowMethodInvoker cqlInvoker = new CQLRowMethodInvoker();
	private CQLEntityProxifier proxifier = new CQLEntityProxifier();

	public CQLSliceQueryIterator(CQLSliceQuery sliceQuery, CQLPersistenceContext context, Iterator iterator,
			PreparedStatement ps) {
		this.context = context;
		this.iterator = iterator;
		this.ps = ps;
		this.meta = sliceQuery.getMeta();
		this.varyingComponentName = sliceQuery.getVaryingComponentName();
		this.varyingComponentClass = sliceQuery.getVaryingComponentClass();
		this.batchSize = sliceQuery.getBatchSize();
	}

	@Override
	public boolean hasNext() {
		if (!iterator.hasNext() && count == batchSize) {
			iterator = context.bindAndExecute(ps, lastVaryingComponentValue).iterator();
			count = 0;
		}
		return iterator.hasNext();
	}

	@Override
	public T next() {

		Row row = iterator.next();
		lastVaryingComponentValue = cqlInvoker.invokeOnRowForType(row, varyingComponentClass, varyingComponentName);
		T clusteredEntity = meta. instanciate();
		mapper.setEagerPropertiesToEntity(row, meta, clusteredEntity);
		count++;
		return proxify(clusteredEntity);
	}

	@Override
	public void remove() {
		throw new UnsupportedOperationException("Cannot remove clustered entity with iterator");
	}

	private T proxify(T clusteredEntity) {
		CQLPersistenceContext duplicate = context.duplicate(clusteredEntity);
		return proxifier.buildProxy(clusteredEntity, duplicate);
	}

}