| /** |
| * 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.zookeeper.server.persistence; |
| |
| import java.io.IOException; |
| |
| import org.apache.jute.Record; |
| import org.apache.zookeeper.server.ServerStats; |
| import org.apache.zookeeper.txn.TxnHeader; |
| |
| /** |
| * Interface for reading transaction logs. |
| * |
| */ |
| public interface TxnLog { |
| |
| /** |
| + * Setter for ServerStats to monitor fsync threshold exceed |
| + * @param serverStats used to update fsyncThresholdExceedCount |
| + */ |
| void setServerStats(ServerStats serverStats); |
| |
| /** |
| * roll the current |
| * log being appended to |
| * @throws IOException |
| */ |
| void rollLog() throws IOException; |
| /** |
| * Append a request to the transaction log |
| * @param hdr the transaction header |
| * @param r the transaction itself |
| * returns true iff something appended, otw false |
| * @throws IOException |
| */ |
| boolean append(TxnHeader hdr, Record r) throws IOException; |
| |
| /** |
| * Start reading the transaction logs |
| * from a given zxid |
| * @param zxid |
| * @return returns an iterator to read the |
| * next transaction in the logs. |
| * @throws IOException |
| */ |
| TxnIterator read(long zxid) throws IOException; |
| |
| /** |
| * the last zxid of the logged transactions. |
| * @return the last zxid of the logged transactions. |
| * @throws IOException |
| */ |
| long getLastLoggedZxid() throws IOException; |
| |
| /** |
| * truncate the log to get in sync with the |
| * leader. |
| * @param zxid the zxid to truncate at. |
| * @throws IOException |
| */ |
| boolean truncate(long zxid) throws IOException; |
| |
| /** |
| * the dbid for this transaction log. |
| * @return the dbid for this transaction log. |
| * @throws IOException |
| */ |
| long getDbId() throws IOException; |
| |
| /** |
| * commmit the trasaction and make sure |
| * they are persisted |
| * @throws IOException |
| */ |
| void commit() throws IOException; |
| |
| /** |
| * close the transactions logs |
| */ |
| void close() throws IOException; |
| /** |
| * an iterating interface for reading |
| * transaction logs. |
| */ |
| public interface TxnIterator { |
| /** |
| * return the transaction header. |
| * @return return the transaction header. |
| */ |
| TxnHeader getHeader(); |
| |
| /** |
| * return the transaction record. |
| * @return return the transaction record. |
| */ |
| Record getTxn(); |
| |
| /** |
| * go to the next transaction record. |
| * @throws IOException |
| */ |
| boolean next() throws IOException; |
| |
| /** |
| * close files and release the |
| * resources |
| * @throws IOException |
| */ |
| void close() throws IOException; |
| } |
| } |
| |