Java tutorial
/* * Copyright 2016-present Open Networking Laboratory * * 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 org.onosproject.store.primitives.impl; import java.util.Collection; import java.util.Map; import java.util.Map.Entry; import java.util.Set; import java.util.concurrent.CompletableFuture; import java.util.concurrent.Executor; import java.util.function.BiFunction; import java.util.function.Consumer; import java.util.function.Function; import java.util.function.Predicate; import java.util.stream.Collectors; import org.onlab.util.Tools; import org.onosproject.store.primitives.TransactionId; import org.onosproject.store.service.AsyncConsistentMap; import org.onosproject.store.service.MapEvent; import org.onosproject.store.service.MapEventListener; import org.onosproject.store.service.MapTransaction; import org.onosproject.store.service.Versioned; import com.google.common.collect.Maps; /** * An {@code AsyncConsistentMap} that maps its operations to operations on a * differently typed {@code AsyncConsistentMap} 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 TranscodingAsyncConsistentMap<K1, V1, K2, V2> implements AsyncConsistentMap<K1, V1> { private final AsyncConsistentMap<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<Versioned<V2>, Versioned<V1>> versionedValueTransform; private final Map<MapEventListener<K1, V1>, InternalBackingMapEventListener> listeners = Maps .newIdentityHashMap(); public TranscodingAsyncConsistentMap(AsyncConsistentMap<K2, V2> backingMap, Function<K1, K2> keyEncoder, Function<K2, K1> keyDecoder, Function<V1, V2> valueEncoder, Function<V2, V1> valueDecoder) { 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.versionedValueTransform = v -> v == null ? null : v.map(valueDecoder); } @Override public String name() { return backingMap.name(); } @Override public CompletableFuture<Integer> size() { return backingMap.size(); } @Override public CompletableFuture<Boolean> containsKey(K1 key) { try { return backingMap.containsKey(keyEncoder.apply(key)); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> containsValue(V1 value) { try { return backingMap.containsValue(valueEncoder.apply(value)); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<V1>> get(K1 key) { try { return backingMap.get(keyEncoder.apply(key)).thenApply(versionedValueTransform); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<V1>> computeIf(K1 key, Predicate<? super V1> condition, BiFunction<? super K1, ? super V1, ? extends V1> remappingFunction) { try { return backingMap .computeIf(keyEncoder.apply(key), v -> condition.test(valueDecoder.apply(v)), (k, v) -> valueEncoder .apply(remappingFunction.apply(keyDecoder.apply(k), valueDecoder.apply(v)))) .thenApply(versionedValueTransform); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<V1>> put(K1 key, V1 value) { try { return backingMap.put(keyEncoder.apply(key), valueEncoder.apply(value)) .thenApply(versionedValueTransform); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<V1>> putAndGet(K1 key, V1 value) { try { return backingMap.putAndGet(keyEncoder.apply(key), valueEncoder.apply(value)) .thenApply(versionedValueTransform); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<V1>> remove(K1 key) { try { return backingMap.remove(keyEncoder.apply(key)).thenApply(versionedValueTransform); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Void> clear() { return backingMap.clear(); } @Override public CompletableFuture<Set<K1>> keySet() { return backingMap.keySet().thenApply(s -> s.stream().map(keyDecoder).collect(Collectors.toSet())); } @Override public CompletableFuture<Collection<Versioned<V1>>> values() { return backingMap.values() .thenApply(c -> c.stream().map(versionedValueTransform).collect(Collectors.toList())); } @Override public CompletableFuture<Set<Entry<K1, Versioned<V1>>>> entrySet() { return backingMap.entrySet().thenApply(s -> s.stream().map( e -> Maps.immutableEntry(keyDecoder.apply(e.getKey()), versionedValueTransform.apply(e.getValue()))) .collect(Collectors.toSet())); } @Override public CompletableFuture<Versioned<V1>> putIfAbsent(K1 key, V1 value) { try { return backingMap.putIfAbsent(keyEncoder.apply(key), valueEncoder.apply(value)) .thenApply(versionedValueTransform); } catch (Exception e) { return Tools.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 Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> remove(K1 key, long version) { try { return backingMap.remove(keyEncoder.apply(key), version); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<V1>> replace(K1 key, V1 value) { try { return backingMap.replace(keyEncoder.apply(key), valueEncoder.apply(value)) .thenApply(versionedValueTransform); } catch (Exception e) { return Tools.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 Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> replace(K1 key, long oldVersion, V1 newValue) { try { return backingMap.replace(keyEncoder.apply(key), oldVersion, valueEncoder.apply(newValue)); } catch (Exception e) { return Tools.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) { InternalBackingMapEventListener backingMapListener = listeners.remove(listener); if (backingMapListener != null) { return backingMap.removeListener(backingMapListener); } else { return CompletableFuture.completedFuture(null); } } @Override public CompletableFuture<Boolean> prepare(MapTransaction<K1, V1> transaction) { try { return backingMap.prepare(transaction.map(keyEncoder, valueEncoder)); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Void> commit(TransactionId transactionId) { return backingMap.commit(transactionId); } @Override public CompletableFuture<Void> rollback(TransactionId transactionId) { return backingMap.rollback(transactionId); } @Override public CompletableFuture<Boolean> prepareAndCommit(MapTransaction<K1, V1> transaction) { try { return backingMap.prepareAndCommit(transaction.map(keyEncoder, valueEncoder)); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public void addStatusChangeListener(Consumer<Status> listener) { backingMap.addStatusChangeListener(listener); } @Override public void removeStatusChangeListener(Consumer<Status> listener) { backingMap.removeStatusChangeListener(listener); } @Override public Collection<Consumer<Status>> statusChangeListeners() { return backingMap.statusChangeListeners(); } 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<K1, V1>(event.name(), keyDecoder.apply(event.key()), event.newValue() != null ? event.newValue().map(valueDecoder) : null, event.oldValue() != null ? event.oldValue().map(valueDecoder) : null)); } } }