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.samza.metadatastore; import com.google.common.collect.ImmutableMap; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; /** * In-memory {@link MetadataStore} with no persistence on disk. */ public class InMemoryMetadataStore implements MetadataStore { private final ConcurrentHashMap<String, byte[]> memStore = new ConcurrentHashMap<>(); @Override public void init() { } @Override public byte[] get(String key) { return memStore.get(key); } @Override public void put(String key, byte[] value) { memStore.put(key, value); } @Override public void delete(String key) { memStore.remove(key); } @Override public Map<String, byte[]> all() { return ImmutableMap.copyOf(memStore); } @Override public void flush() { } @Override public void close() { } }