| /* |
| * 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.drill.exec.coord.store; |
| |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import javax.annotation.Nullable; |
| |
| import com.google.common.base.Function; |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.Iterators; |
| import com.google.common.collect.Maps; |
| |
| public abstract class BaseTransientStore<V> implements TransientStore<V> { |
| private final Set<TransientStoreListener> listeners = Collections.newSetFromMap( |
| Maps.<TransientStoreListener, Boolean>newConcurrentMap()); |
| |
| protected final TransientStoreConfig<V> config; |
| |
| protected BaseTransientStore(final TransientStoreConfig<V> config) { |
| this.config = Preconditions.checkNotNull(config, "config cannot be null"); |
| } |
| |
| public TransientStoreConfig<V> getConfig() { |
| return config; |
| } |
| |
| @Override |
| public Iterator<String> keys() { |
| return Iterators.transform(entries(), new Function<Map.Entry<String, V>, String>() { |
| @Nullable |
| @Override |
| public String apply(@Nullable Map.Entry<String, V> input) { |
| return input.getKey(); |
| } |
| }); |
| } |
| |
| @Override |
| public Iterator<V> values() { |
| return Iterators.transform(entries(), new Function<Map.Entry<String, V>, V>() { |
| @Nullable |
| @Override |
| public V apply(final Map.Entry<String, V> entry) { |
| return entry.getValue(); |
| } |
| }); |
| } |
| |
| protected void fireListeners(final TransientStoreEvent<?> event) { |
| for (final TransientStoreListener listener:listeners) { |
| listener.onChange(event); |
| } |
| } |
| |
| @Override |
| public void addListener(final TransientStoreListener listener) { |
| listeners.add(Preconditions.checkNotNull(listener, "listener cannot be null")); |
| } |
| |
| @Override |
| public void removeListener(final TransientStoreListener listener) { |
| listeners.remove(Preconditions.checkNotNull(listener, "listener cannot be null")); |
| } |
| } |