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/***********************************************************************************************************************
 * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
 *
 * 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 eu.stratosphere.addons.hbase.common;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.util.Base64;

/**
 * Utility for {@link TableInputFormat}
 */
public class HBaseUtil {

	/**
	 * Writes the given scan into a Base64 encoded string.
	 * 
	 * @param scan
	 *        The scan to write out.
	 * @return The scan saved in a Base64 encoded string.
	 * @throws IOException
	 *         When writing the scan fails.
	 */
	static String convertScanToString(Scan scan) throws IOException {
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		DataOutputStream dos = new DataOutputStream(out);
		scan.write(dos);
		return Base64.encodeBytes(out.toByteArray());
	}

	/**
	 * Converts the given Base64 string back into a Scan instance.
	 * 
	 * @param base64
	 *        The scan details.
	 * @return The newly created Scan instance.
	 * @throws IOException
	 *         When reading the scan instance fails.
	 */
	public static Scan convertStringToScan(String base64) throws IOException {
		ByteArrayInputStream bis = new ByteArrayInputStream(Base64.decode(base64));
		DataInputStream dis = new DataInputStream(bis);
		Scan scan = new Scan();
		scan.readFields(dis);
		return scan;
	}
}