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 * <p/> * http://www.apache.org/licenses/LICENSE-2.0 * <p/> * 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.drill.exec.testing.store; import java.util.Iterator; import java.util.Map; import java.util.concurrent.ConcurrentMap; import com.google.common.collect.Iterables; import com.google.common.collect.Maps; import org.apache.drill.exec.store.sys.BasePersistentStore; import org.apache.drill.exec.store.sys.PersistentStoreMode; public class NoWriteLocalStore<V> extends BasePersistentStore<V> { private final ConcurrentMap<String, V> store = Maps.newConcurrentMap(); public void delete(final String key) { store.remove(key); } @Override public PersistentStoreMode getMode() { return PersistentStoreMode.PERSISTENT; } @Override public V get(final String key) { return store.get(key); } @Override public void put(final String key, final V value) { store.put(key, value); } @Override public boolean putIfAbsent(final String key, final V value) { final V old = store.putIfAbsent(key, value); return value != old; } @Override public Iterator<Map.Entry<String, V>> getRange(final int skip, final int take) { return Iterables.limit(Iterables.skip(store.entrySet(), skip), take).iterator(); } @Override public void close() throws Exception { store.clear(); } }