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.tephra.snapshot; import com.google.common.collect.Maps; import it.unimi.dsi.fastutil.longs.LongArrayList; import org.apache.tephra.TransactionManager; import org.apache.tephra.persist.TransactionSnapshot; import java.io.IOException; import java.util.Map; import java.util.NavigableMap; /** * Handles serialization/deserialization of a {@link TransactionSnapshot} * and its elements to {@code byte[]}. */ public class SnapshotCodecV2 extends DefaultSnapshotCodec { @Override public int getVersion() { return 2; } @Override protected void encodeInProgress(BinaryEncoder encoder, Map<Long, TransactionManager.InProgressTx> inProgress) throws IOException { if (!inProgress.isEmpty()) { encoder.writeInt(inProgress.size()); for (Map.Entry<Long, TransactionManager.InProgressTx> entry : inProgress.entrySet()) { encoder.writeLong(entry.getKey()); // tx id encoder.writeLong(entry.getValue().getExpiration()); encoder.writeLong(entry.getValue().getVisibilityUpperBound()); encoder.writeInt(entry.getValue().getType().ordinal()); } } encoder.writeInt(0); // zero denotes end of list as per AVRO spec } @Override protected NavigableMap<Long, TransactionManager.InProgressTx> decodeInProgress(BinaryDecoder decoder) throws IOException { int size = decoder.readInt(); NavigableMap<Long, TransactionManager.InProgressTx> inProgress = Maps.newTreeMap(); while (size != 0) { // zero denotes end of list as per AVRO spec for (int remaining = size; remaining > 0; --remaining) { long txId = decoder.readLong(); long expiration = decoder.readLong(); long visibilityUpperBound = decoder.readLong(); int txTypeIdx = decoder.readInt(); TransactionManager.InProgressType txType; try { txType = TransactionManager.InProgressType.values()[txTypeIdx]; } catch (ArrayIndexOutOfBoundsException e) { throw new IOException("Type enum ordinal value is out of range: " + txTypeIdx); } inProgress.put(txId, new TransactionManager.InProgressTx(visibilityUpperBound, expiration, txType, new LongArrayList())); } size = decoder.readInt(); } return inProgress; } }