| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.contrib.bkjournal; |
| |
| import java.io.IOException; |
| import java.util.Comparator; |
| import org.apache.zookeeper.ZooKeeper; |
| import org.apache.zookeeper.CreateMode; |
| import org.apache.zookeeper.ZooDefs.Ids; |
| import org.apache.zookeeper.KeeperException; |
| |
| import org.apache.hadoop.hdfs.protocol.HdfsConstants; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * Utility class for storing the metadata associated |
| * with a single edit log segment, stored in a single ledger |
| */ |
| public class EditLogLedgerMetadata { |
| static final Log LOG = LogFactory.getLog(EditLogLedgerMetadata.class); |
| |
| private String zkPath; |
| private final long ledgerId; |
| private final int version; |
| private final long firstTxId; |
| private long lastTxId; |
| private boolean inprogress; |
| |
| public static final Comparator COMPARATOR |
| = new Comparator<EditLogLedgerMetadata>() { |
| public int compare(EditLogLedgerMetadata o1, |
| EditLogLedgerMetadata o2) { |
| if (o1.firstTxId < o2.firstTxId) { |
| return -1; |
| } else if (o1.firstTxId == o2.firstTxId) { |
| return 0; |
| } else { |
| return 1; |
| } |
| } |
| }; |
| |
| EditLogLedgerMetadata(String zkPath, int version, |
| long ledgerId, long firstTxId) { |
| this.zkPath = zkPath; |
| this.ledgerId = ledgerId; |
| this.version = version; |
| this.firstTxId = firstTxId; |
| this.lastTxId = HdfsConstants.INVALID_TXID; |
| this.inprogress = true; |
| } |
| |
| EditLogLedgerMetadata(String zkPath, int version, long ledgerId, |
| long firstTxId, long lastTxId) { |
| this.zkPath = zkPath; |
| this.ledgerId = ledgerId; |
| this.version = version; |
| this.firstTxId = firstTxId; |
| this.lastTxId = lastTxId; |
| this.inprogress = false; |
| } |
| |
| String getZkPath() { |
| return zkPath; |
| } |
| |
| long getFirstTxId() { |
| return firstTxId; |
| } |
| |
| long getLastTxId() { |
| return lastTxId; |
| } |
| |
| long getLedgerId() { |
| return ledgerId; |
| } |
| |
| int getVersion() { |
| return version; |
| } |
| |
| boolean isInProgress() { |
| return this.inprogress; |
| } |
| |
| void finalizeLedger(long newLastTxId) { |
| assert this.lastTxId == HdfsConstants.INVALID_TXID; |
| this.lastTxId = newLastTxId; |
| this.inprogress = false; |
| } |
| |
| static EditLogLedgerMetadata read(ZooKeeper zkc, String path) |
| throws IOException, KeeperException.NoNodeException { |
| try { |
| byte[] data = zkc.getData(path, false, null); |
| String[] parts = new String(data).split(";"); |
| if (parts.length == 3) { |
| int version = Integer.valueOf(parts[0]); |
| long ledgerId = Long.valueOf(parts[1]); |
| long txId = Long.valueOf(parts[2]); |
| return new EditLogLedgerMetadata(path, version, ledgerId, txId); |
| } else if (parts.length == 4) { |
| int version = Integer.valueOf(parts[0]); |
| long ledgerId = Long.valueOf(parts[1]); |
| long firstTxId = Long.valueOf(parts[2]); |
| long lastTxId = Long.valueOf(parts[3]); |
| return new EditLogLedgerMetadata(path, version, ledgerId, |
| firstTxId, lastTxId); |
| } else { |
| throw new IOException("Invalid ledger entry, " |
| + new String(data)); |
| } |
| } catch(KeeperException.NoNodeException nne) { |
| throw nne; |
| } catch(Exception e) { |
| throw new IOException("Error reading from zookeeper", e); |
| } |
| } |
| |
| void write(ZooKeeper zkc, String path) |
| throws IOException, KeeperException.NodeExistsException { |
| this.zkPath = path; |
| String finalisedData; |
| if (inprogress) { |
| finalisedData = String.format("%d;%d;%d", |
| version, ledgerId, firstTxId); |
| } else { |
| finalisedData = String.format("%d;%d;%d;%d", |
| version, ledgerId, firstTxId, lastTxId); |
| } |
| try { |
| zkc.create(path, finalisedData.getBytes(), |
| Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); |
| } catch (KeeperException.NodeExistsException nee) { |
| throw nee; |
| } catch (Exception e) { |
| throw new IOException("Error creating ledger znode"); |
| } |
| } |
| |
| boolean verify(ZooKeeper zkc, String path) { |
| try { |
| EditLogLedgerMetadata other = read(zkc, path); |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("Verifying " + this.toString() |
| + " against " + other); |
| } |
| return other == this; |
| } catch (Exception e) { |
| LOG.error("Couldn't verify data in " + path, e); |
| return false; |
| } |
| } |
| |
| public boolean equals(Object o) { |
| if (!(o instanceof EditLogLedgerMetadata)) { |
| return false; |
| } |
| EditLogLedgerMetadata ol = (EditLogLedgerMetadata)o; |
| return ledgerId == ol.ledgerId |
| && firstTxId == ol.firstTxId |
| && lastTxId == ol.lastTxId |
| && version == ol.version; |
| } |
| |
| public int hashCode() { |
| int hash = 1; |
| hash = hash * 31 + (int)ledgerId; |
| hash = hash * 31 + (int)firstTxId; |
| hash = hash * 31 + (int)lastTxId; |
| hash = hash * 31 + (int)version; |
| return hash; |
| } |
| |
| public String toString() { |
| return "[LedgerId:"+ledgerId + |
| ", firstTxId:" + firstTxId + |
| ", lastTxId:" + lastTxId + |
| ", version:" + version + "]"; |
| } |
| |
| } |