Java tutorial
/* * * 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.bookkeeper.client; import java.io.IOException; import java.security.GeneralSecurityException; import org.apache.bookkeeper.client.AsyncCallback.OpenCallback; import org.apache.bookkeeper.client.BookKeeper.DigestType; import org.apache.bookkeeper.util.StringUtils; import org.apache.log4j.Logger; import org.apache.zookeeper.KeeperException; import org.apache.zookeeper.AsyncCallback.DataCallback; import org.apache.bookkeeper.proto.BookkeeperInternalCallbacks.GenericCallback; import org.apache.zookeeper.data.Stat; /** * Encapsulates the ledger open operation * */ class LedgerOpenOp implements DataCallback { static final Logger LOG = Logger.getLogger(LedgerOpenOp.class); BookKeeper bk; long ledgerId; OpenCallback cb; Object ctx; LedgerHandle lh; byte[] passwd; DigestType digestType; /** * Constructor. * * @param bk * @param ledgerId * @param digestType * @param passwd * @param cb * @param ctx */ public LedgerOpenOp(BookKeeper bk, long ledgerId, DigestType digestType, byte[] passwd, OpenCallback cb, Object ctx) { this.bk = bk; this.ledgerId = ledgerId; this.passwd = passwd; this.cb = cb; this.ctx = ctx; this.digestType = digestType; } /** * Inititates the ledger open operation */ public void initiate() { /** * Asynchronously read the ledger metadata node. */ bk.getZkHandle().getData(StringUtils.getLedgerNodePath(ledgerId), false, this, ctx); } /** * Implements ZooKeeper data callback. * @see org.apache.zookeeper.AsyncCallback.DataCallback#processResult(int, String, Object, byte[], Stat) */ public void processResult(int rc, String path, Object ctx, byte[] data, Stat stat) { if (rc == KeeperException.Code.NONODE.intValue()) { if (LOG.isDebugEnabled()) { LOG.debug("No such ledger: " + ledgerId, KeeperException.create(KeeperException.Code.get(rc), path)); } cb.openComplete(BKException.Code.NoSuchLedgerExistsException, null, this.ctx); return; } if (rc != KeeperException.Code.OK.intValue()) { LOG.error("Could not read metadata for ledger: " + ledgerId, KeeperException.create(KeeperException.Code.get(rc), path)); cb.openComplete(BKException.Code.ZKException, null, this.ctx); return; } LedgerMetadata metadata; try { metadata = LedgerMetadata.parseConfig(data); } catch (IOException e) { LOG.error("Could not parse ledger metadata for ledger: " + ledgerId, e); cb.openComplete(BKException.Code.ZKException, null, this.ctx); return; } try { lh = new LedgerHandle(bk, ledgerId, metadata, digestType, passwd); } catch (GeneralSecurityException e) { LOG.error("Security exception while opening ledger: " + ledgerId, e); cb.openComplete(BKException.Code.DigestNotInitializedException, null, this.ctx); return; } if (metadata.close != LedgerMetadata.NOTCLOSED) { // Ledger was closed properly cb.openComplete(BKException.Code.OK, lh, this.ctx); return; } lh.recover(new GenericCallback<Void>() { @Override public void operationComplete(int rc, Void result) { if (rc != BKException.Code.OK) { cb.openComplete(BKException.Code.LedgerRecoveryException, null, LedgerOpenOp.this.ctx); } else { cb.openComplete(BKException.Code.OK, lh, LedgerOpenOp.this.ctx); } } }); } }