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Java client for Arcus memcached
There is a newer version: 1.14.0
/*
 * arcus-java-client : Arcus Java client
 * Copyright 2014 JaM2in Co., Ltd.
 *
 * 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.io.ByteArrayOutputStream;
import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.Collections;

import net.spy.memcached.collection.BTreeFindPositionWithGet;
import net.spy.memcached.collection.CollectionResponse;
import net.spy.memcached.ops.BTreeFindPositionWithGetOperation;
import net.spy.memcached.ops.CollectionOperationStatus;
import net.spy.memcached.ops.OperationCallback;
import net.spy.memcached.ops.OperationState;
import net.spy.memcached.ops.OperationStatus;

public class BTreeFindPositionWithGetOperationImpl extends OperationImpl implements
		BTreeFindPositionWithGetOperation {

	private final ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();

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

	private static final OperationStatus END = new CollectionOperationStatus(
			true, "END", CollectionResponse.END);
	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 BTreeFindPositionWithGet get;

	protected int position = 0;
	protected int flags = 0;
	protected int count = 0;
	protected int index = 0;
	protected int pos = 0;
	protected int posDiff = 0;
	protected byte[] data = null;
	protected int readOffset = 0;
	protected byte lookingFor = '\0';
	protected int spaceCount = 0;

	private Boolean hasEFlag = null;

	public BTreeFindPositionWithGetOperationImpl(String key,
			BTreeFindPositionWithGet get, OperationCallback cb) {
		super(cb);
		this.key = key;
		this.get = get;
	}

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

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

		if (line.startsWith("VALUE ")) {
			// VALUE    \r\n
			String[] stuff = line.split(" ");
			assert stuff.length == 5;

			position = Integer.parseInt(stuff[1]);
			flags = Integer.parseInt(stuff[2]);
			count = Integer.parseInt(stuff[3]);
			index = Integer.parseInt(stuff[4]);

			assert count > 0;
			// position counter
			pos = position - index;
			posDiff = 1; 

			// start to read actual data
			setReadType(OperationReadType.DATA);
		} else {
			OperationStatus status = matchStatus(line, END, NOT_FOUND, NOT_FOUND_ELEMENT,
												UNREADABLE, TYPE_MISMATCH, BKEY_MISMATCH);
			if (getLogger().isDebugEnabled()) {
				getLogger().debug(status);
			}
			getCallback().receivedStatus(status);
			transitionState(OperationState.COMPLETE);
		}
	}

	@Override
	public void handleRead(ByteBuffer bb) {
		// Decode a data header.
		if (lookingFor == '\0' && data == null) {
			for (int i = 0; bb.remaining() > 0; i++) {
				byte b = bb.get();
				if (b == ' ') { // Handle spaces to parse the header.
					// One-time check to find if this responses have eflags.
					if (hasEFlag == null && spaceCount == 1) {
						String[] chunk = new String(byteBuffer.toByteArray()).split(" ");
						if (chunk[1].startsWith("0x")) {
							hasEFlag = true;
						} else {
							hasEFlag = false;
						}
					}

					spaceCount++;

					// Parse the value header.
					// FIXME this is not cool... please fix this :-(
					int spaceReduced = (hasEFlag != null && hasEFlag) ? 1 : 0;
					if (get.headerReady(spaceCount - spaceReduced)) {
						get.decodeItemHeader(new String(byteBuffer.toByteArray()));
						data = new byte[get.getDataLength()];
						byteBuffer.reset();
						spaceCount = 0;
						hasEFlag = null;
						break;
					}
				}
				else if (b == '\r') { // Ready to finish.
					continue;
				}
				else if (b == '\n') { // Finish the operation.
					OperationStatus status = matchStatus(byteBuffer.toString(), END,
							NOT_FOUND, NOT_FOUND_ELEMENT, UNREADABLE, TYPE_MISMATCH, BKEY_MISMATCH);

					if (getLogger().isDebugEnabled()) {
						getLogger().debug("Get complete!");
					}
					getCallback().receivedStatus(status);
					transitionState(OperationState.COMPLETE);
					data = null;
					break;
				}
				
				// Write to the result ByteBuffer 
				byteBuffer.write(b);
			}
			return;
		}
		
		// Read data
		assert key != null;
		assert data != null;
		// This will be the case, because we'll clear them when it's not.
		assert readOffset <= data.length
			: "readOffset is " + readOffset + " data.length is " + data.length;

		if (getLogger().isDebugEnabled()) {
			getLogger().debug("readOffset: %d, length: %d", readOffset, data.length);
		}
		
		if (lookingFor == '\0') {
			int toRead = data.length - readOffset;
			int available = bb.remaining();
			toRead = Math.min(toRead, available);

			if (getLogger().isDebugEnabled()) {
				getLogger().debug("Reading %d bytes", toRead);
			}
			
			bb.get(data, readOffset, toRead);
			readOffset += toRead;
		}
		
		if (lookingFor == '\0' && readOffset == data.length) {
			// put an element data.
			BTreeFindPositionWithGetOperation.Callback cb = (BTreeFindPositionWithGetOperation.Callback) getCallback();
			cb.gotData(key, flags, pos, get.getBkey(), get.getEflag(), data);
			
			// next position.
			pos += posDiff;
			lookingFor = '\r';
		}

		if (lookingFor != '\0' && bb.hasRemaining()) {
			do {
				byte tmp = bb.get();
				assert tmp == lookingFor : "Expecting " + lookingFor + ", got "
						+ (char) tmp;

				switch (lookingFor) {
				case '\r':
					lookingFor = '\n';
					break;
				case '\n':
					lookingFor = '\0';
					break;
				default:
					assert false : "Looking for unexpected char: "
							+ (char) lookingFor;
				}
			} while (lookingFor != '\0' && bb.hasRemaining());

			if (lookingFor == '\0') {
				data = null;
				readOffset = 0;
			}
		}
	}

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

		ByteBuffer bb = ByteBuffer.allocate(cmd.length() + key.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);
	}
}