Java tutorial
/* * Copyright 2016-present Open Networking Foundation * * Licensed 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 io.atomix.core.map.impl; import com.google.common.collect.Maps; import io.atomix.core.collection.AsyncDistributedCollection; import io.atomix.core.collection.impl.TranscodingAsyncDistributedCollection; import io.atomix.core.map.AsyncDistributedMap; import io.atomix.core.map.DistributedMap; import io.atomix.core.map.MapEvent; import io.atomix.core.map.MapEventListener; import io.atomix.core.set.AsyncDistributedSet; import io.atomix.core.set.impl.TranscodingAsyncDistributedSet; import io.atomix.primitive.impl.DelegatingAsyncPrimitive; import io.atomix.utils.concurrent.Futures; import java.time.Duration; import java.util.Map; import java.util.Map.Entry; import java.util.concurrent.CompletableFuture; import java.util.concurrent.Executor; import java.util.function.BiFunction; import java.util.function.Function; import java.util.stream.Collectors; /** * An {@code AsyncDistributedMap} that maps its operations to operations on a * differently typed {@code AsyncDistributedMap} by transcoding operation inputs and outputs. * * @param <K2> key type of other map * @param <V2> value type of other map * @param <K1> key type of this map * @param <V1> value type of this map */ public class TranscodingAsyncDistributedMap<K1, V1, K2, V2> extends DelegatingAsyncPrimitive implements AsyncDistributedMap<K1, V1> { private final AsyncDistributedMap<K2, V2> backingMap; private final Function<K1, K2> keyEncoder; private final Function<K2, K1> keyDecoder; private final Function<V2, V1> valueDecoder; private final Function<V1, V2> valueEncoder; private final Function<Entry<K2, V2>, Entry<K1, V1>> entryDecoder; private final Function<Entry<K1, V1>, Entry<K2, V2>> entryEncoder; private final Map<MapEventListener<K1, V1>, InternalBackingMapEventListener> listeners = Maps .newIdentityHashMap(); public TranscodingAsyncDistributedMap(AsyncDistributedMap<K2, V2> backingMap, Function<K1, K2> keyEncoder, Function<K2, K1> keyDecoder, Function<V1, V2> valueEncoder, Function<V2, V1> valueDecoder) { super(backingMap); this.backingMap = backingMap; this.keyEncoder = k -> k == null ? null : keyEncoder.apply(k); this.keyDecoder = k -> k == null ? null : keyDecoder.apply(k); this.valueEncoder = v -> v == null ? null : valueEncoder.apply(v); this.valueDecoder = v -> v == null ? null : valueDecoder.apply(v); this.entryDecoder = e -> e == null ? null : Maps.immutableEntry(keyDecoder.apply(e.getKey()), valueDecoder.apply(e.getValue())); this.entryEncoder = e -> e == null ? null : Maps.immutableEntry(keyEncoder.apply(e.getKey()), valueEncoder.apply(e.getValue())); } @Override public CompletableFuture<Integer> size() { return backingMap.size(); } @Override public CompletableFuture<Boolean> isEmpty() { return backingMap.isEmpty(); } @Override public CompletableFuture<Boolean> containsKey(K1 key) { try { return backingMap.containsKey(keyEncoder.apply(key)); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> containsValue(V1 value) { try { return backingMap.containsValue(valueEncoder.apply(value)); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<V1> get(K1 key) { try { return backingMap.get(keyEncoder.apply(key)).thenApply(valueDecoder); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<V1> getOrDefault(K1 key, V1 defaultValue) { try { return backingMap.getOrDefault(keyEncoder.apply(key), valueEncoder.apply(defaultValue)) .thenApply(valueDecoder); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<V1> put(K1 key, V1 value) { try { return backingMap.put(keyEncoder.apply(key), valueEncoder.apply(value)).thenApply(valueDecoder); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<Void> putAll(Map<? extends K1, ? extends V1> map) { return backingMap.putAll(map.entrySet().stream().map(e -> entryEncoder.apply((Map.Entry<K1, V1>) e)) .collect(Collectors.toMap(e -> e.getKey(), e -> e.getValue()))); } @Override public CompletableFuture<V1> remove(K1 key) { try { return backingMap.remove(keyEncoder.apply(key)).thenApply(valueDecoder); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<V1> computeIfAbsent(K1 key, Function<? super K1, ? extends V1> mappingFunction) { return backingMap .computeIfAbsent(keyEncoder.apply(key), (k) -> valueEncoder.apply(mappingFunction.apply(keyDecoder.apply(k)))) .thenApply(valueDecoder); } @Override public CompletableFuture<V1> computeIfPresent(K1 key, BiFunction<? super K1, ? super V1, ? extends V1> remappingFunction) { return backingMap .computeIfPresent(keyEncoder.apply(key), (k, v) -> valueEncoder .apply(remappingFunction.apply(keyDecoder.apply(k), valueDecoder.apply(v)))) .thenApply(valueDecoder); } @Override public CompletableFuture<V1> compute(K1 key, BiFunction<? super K1, ? super V1, ? extends V1> remappingFunction) { return backingMap .compute(keyEncoder.apply(key), (k, v) -> valueEncoder .apply(remappingFunction.apply(keyDecoder.apply(k), valueDecoder.apply(v)))) .thenApply(valueDecoder); } @Override public CompletableFuture<Void> clear() { return backingMap.clear(); } @Override public AsyncDistributedSet<K1> keySet() { return new TranscodingAsyncDistributedSet<>(backingMap.keySet(), keyEncoder, keyDecoder); } @Override public AsyncDistributedCollection<V1> values() { return new TranscodingAsyncDistributedCollection<>(backingMap.values(), valueEncoder, valueDecoder); } @Override public AsyncDistributedSet<Entry<K1, V1>> entrySet() { return new TranscodingAsyncDistributedSet<>(backingMap.entrySet(), entryEncoder, entryDecoder); } @Override public CompletableFuture<V1> putIfAbsent(K1 key, V1 value) { try { return backingMap.putIfAbsent(keyEncoder.apply(key), valueEncoder.apply(value)).thenApply(valueDecoder); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> remove(K1 key, V1 value) { try { return backingMap.remove(keyEncoder.apply(key), valueEncoder.apply(value)); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<V1> replace(K1 key, V1 value) { try { return backingMap.replace(keyEncoder.apply(key), valueEncoder.apply(value)).thenApply(valueDecoder); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> replace(K1 key, V1 oldValue, V1 newValue) { try { return backingMap.replace(keyEncoder.apply(key), valueEncoder.apply(oldValue), valueEncoder.apply(newValue)); } catch (Exception e) { return Futures.exceptionalFuture(e); } } @Override public CompletableFuture<Void> addListener(MapEventListener<K1, V1> listener, Executor executor) { synchronized (listeners) { InternalBackingMapEventListener backingMapListener = listeners.computeIfAbsent(listener, k -> new InternalBackingMapEventListener(listener)); return backingMap.addListener(backingMapListener, executor); } } @Override public CompletableFuture<Void> removeListener(MapEventListener<K1, V1> listener) { synchronized (listeners) { InternalBackingMapEventListener backingMapListener = listeners.remove(listener); if (backingMapListener != null) { return backingMap.removeListener(backingMapListener); } else { return CompletableFuture.completedFuture(null); } } } @Override public DistributedMap<K1, V1> sync(Duration operationTimeout) { return new BlockingDistributedMap<>(this, operationTimeout.toMillis()); } private class InternalBackingMapEventListener implements MapEventListener<K2, V2> { private final MapEventListener<K1, V1> listener; InternalBackingMapEventListener(MapEventListener<K1, V1> listener) { this.listener = listener; } @Override public void event(MapEvent<K2, V2> event) { listener.event(new MapEvent<>(event.type(), keyDecoder.apply(event.key()), event.newValue() != null ? valueDecoder.apply(event.newValue()) : null, event.oldValue() != null ? valueDecoder.apply(event.oldValue()) : null)); } } }