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Java client for Arcus memcached
There is a newer version: 1.13.2
/*
 * arcus-java-client : Arcus Java client
 * Copyright 2010-2014 NAVER Corp.
 *
 * 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 net.spy.memcached.protocol.ascii;

import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.Collections;

import net.spy.memcached.KeyUtil;
import net.spy.memcached.collection.BTreeFindPosition;
import net.spy.memcached.collection.CollectionResponse;
import net.spy.memcached.ops.APIType;
import net.spy.memcached.ops.BTreeFindPositionOperation;
import net.spy.memcached.ops.CollectionOperationStatus;
import net.spy.memcached.ops.OperationCallback;
import net.spy.memcached.ops.OperationState;
import net.spy.memcached.ops.OperationStatus;
import net.spy.memcached.ops.OperationType;

public class BTreeFindPositionOperationImpl extends OperationImpl implements
		BTreeFindPositionOperation {

	private static final OperationStatus GET_CANCELED = new CollectionOperationStatus(
			false, "collection canceled", CollectionResponse.CANCELED);

	private static final OperationStatus POSITION = new CollectionOperationStatus(
			true, "POSITION", CollectionResponse.OK); // OK is arbitrary response
	private static final OperationStatus NOT_FOUND = new CollectionOperationStatus(
			false, "NOT_FOUND", CollectionResponse.NOT_FOUND);
	private static final OperationStatus UNREADABLE = new CollectionOperationStatus(
			false, "UNREADABLE", CollectionResponse.UNREADABLE);
	private static final OperationStatus BKEY_MISMATCH = new CollectionOperationStatus(
			false, "BKEY_MISMATCH", CollectionResponse.BKEY_MISMATCH);
	private static final OperationStatus TYPE_MISMATCH = new CollectionOperationStatus(
			false, "TYPE_MISMATCH", CollectionResponse.TYPE_MISMATCH);
	private static final OperationStatus NOT_FOUND_ELEMENT = new CollectionOperationStatus(
			false, "NOT_FOUND_ELEMENT", CollectionResponse.NOT_FOUND_ELEMENT);

	protected final String key;
	protected final BTreeFindPosition get;

	protected byte[] data = null;
	protected int readOffset = 0;
	protected byte lookingFor = '\0';
	protected int spaceCount = 0;

	public BTreeFindPositionOperationImpl(String key, BTreeFindPosition get,
			OperationCallback cb) {
		super(cb);
		this.key = key;
		this.get = get;
		setAPIType(APIType.BOP_POSITION);
		setOperationType(OperationType.READ);
	}

	@Override
	public BTreeFindPosition getGet() {
		return get;
	}

	@Override
	public void handleLine(String line) {
		if (getLogger().isDebugEnabled()) {
			getLogger().debug("Got line %s", line);
		}

		Integer position = null;

		if (line.startsWith("POSITION=")) {
			String[] stuff = line.split("=");
			assert stuff.length == 2;
			assert "POSITION".equals(stuff[0]);

			// FIXME exception-based conversion.
			try {
				// expected : POSITION= : 0 or positive integer
				position = Integer.parseInt(stuff[1]);
				BTreeFindPositionOperation.Callback cb = (BTreeFindPositionOperation.Callback) getCallback();
				cb.gotData(position);
				getCallback().receivedStatus(POSITION);
			} catch (Exception e) {
				// expected : 
			}
		} else {
			OperationStatus status = matchStatus(line, NOT_FOUND, UNREADABLE,
					BKEY_MISMATCH, TYPE_MISMATCH, NOT_FOUND_ELEMENT);
			if (getLogger().isDebugEnabled()) {
				getLogger().debug(status);
			}
			getCallback().receivedStatus(status);
		}

		transitionState(OperationState.COMPLETE);
	}

	@Override
	public void initialize() {
		String cmd = get.getCommand();
		String args = get.stringify();

		ByteBuffer bb = ByteBuffer.allocate(KeyUtil.getKeyBytes(key).length
				+ cmd.length() + args.length() + 16);

		setArguments(bb, cmd, key, args);
		bb.flip();
		setBuffer(bb);

		if (getLogger().isDebugEnabled()) {
			getLogger().debug(
					"Request in ascii protocol: "
							+ (new String(bb.array()))
									.replace("\r\n", "\\r\\n"));
		}
	}

	@Override
	protected void wasCancelled() {
		getCallback().receivedStatus(GET_CANCELED);
	}

	public Collection getKeys() {
		return Collections.singleton(key);
	}

}