Java tutorial
/* * Copyright 2016 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 com.google.common.collect.ImmutableMultiset; import com.google.common.collect.Maps; import com.google.common.collect.Multiset; import org.onlab.util.Tools; import org.onosproject.store.service.AsyncConsistentMultimap; import org.onosproject.store.service.Versioned; import java.util.Collection; import java.util.EnumSet; import java.util.Map; import java.util.Set; import java.util.concurrent.CompletableFuture; import java.util.function.BiConsumer; import java.util.function.BinaryOperator; import java.util.function.Consumer; import java.util.function.Function; import java.util.function.Supplier; import java.util.stream.Collector; import java.util.stream.Collectors; /** * An {@link AsyncConsistentMultimap} that maps its operation to operations to * a differently typed {@link AsyncConsistentMultimap} by transcoding operation * inputs and outputs while maintaining version numbers. * * @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 TranscodingAsyncConsistentMultimap<K1, V1, K2, V2> implements AsyncConsistentMultimap<K1, V1> { private final AsyncConsistentMultimap<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<? extends Versioned<V2>, ? extends Versioned<V1>> versionedValueTransform; private final Function<Versioned<Collection<? extends V2>>, Versioned<Collection<? extends V1>>> versionedValueCollectionDecode; private final Function<Collection<? extends V1>, Collection<V2>> valueCollectionEncode; public TranscodingAsyncConsistentMultimap(AsyncConsistentMultimap<K2, V2> backingMap, Function<K1, K2> keyEncoder, Function<K2, K1> keyDecoder, Function<V2, V1> valueDecoder, Function<V1, V2> valueEncoder) { this.backingMap = backingMap; this.keyEncoder = k -> k == null ? null : keyEncoder.apply(k); this.keyDecoder = k -> k == null ? null : keyDecoder.apply(k); this.valueDecoder = v -> v == null ? null : valueDecoder.apply(v); this.valueEncoder = v -> v == null ? null : valueEncoder.apply(v); this.versionedValueTransform = v -> v == null ? null : v.map(valueDecoder); this.versionedValueCollectionDecode = v -> v == null ? null : new Versioned<>(v.value().stream().map(valueDecoder).collect(Collectors.toSet()), v.version(), v.creationTime()); this.valueCollectionEncode = v -> v == null ? null : v.stream().map(valueEncoder).collect(Collectors.toSet()); } @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 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<Boolean> containsEntry(K1 key, V1 value) { try { return backingMap.containsEntry(keyEncoder.apply(key), valueEncoder.apply(value)); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> put(K1 key, V1 value) { try { return backingMap.put(keyEncoder.apply(key), valueEncoder.apply(value)); } 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> removeAll(K1 key, Collection<? extends V1> values) { try { return backingMap.removeAll(keyEncoder.apply(key), values.stream().map(valueEncoder).collect(Collectors.toSet())); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<Collection<? extends V1>>> removeAll(K1 key) { try { return backingMap.removeAll(keyEncoder.apply(key)).thenApply(versionedValueCollectionDecode); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Boolean> putAll(K1 key, Collection<? extends V1> values) { try { return backingMap.putAll(keyEncoder.apply(key), valueCollectionEncode.apply(values)); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Versioned<Collection<? extends V1>>> replaceValues(K1 key, Collection<V1> values) { try { return backingMap.replaceValues(keyEncoder.apply(key), valueCollectionEncode.apply(values)) .thenApply(versionedValueCollectionDecode); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Void> clear() { return backingMap.clear(); } @Override public CompletableFuture<Versioned<Collection<? extends V1>>> get(K1 key) { try { return backingMap.get(keyEncoder.apply(key)).thenApply(versionedValueCollectionDecode); } catch (Exception e) { return Tools.exceptionalFuture(e); } } @Override public CompletableFuture<Set<K1>> keySet() { return backingMap.keySet().thenApply(s -> s.stream().map(keyDecoder).collect(Collectors.toSet())); } @Override public CompletableFuture<Multiset<K1>> keys() { return backingMap.keys().thenApply(s -> s.stream().map(keyDecoder).collect(new MultisetCollector<>())); } @Override public CompletableFuture<Multiset<V1>> values() { return backingMap.values().thenApply(s -> s.stream().map(valueDecoder).collect(new MultisetCollector<>())); } @Override public CompletableFuture<Collection<Map.Entry<K1, V1>>> entries() { return backingMap.entries() .thenApply(s -> s.stream().map( e -> Maps.immutableEntry(keyDecoder.apply(e.getKey()), valueDecoder.apply(e.getValue()))) .collect(Collectors.toSet())); } @Override public CompletableFuture<Map<K1, Collection<V1>>> asMap() { throw new UnsupportedOperationException("Unsupported operation."); } @Override public String name() { return backingMap.name(); } @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 MultisetCollector<T> implements Collector<T, ImmutableMultiset.Builder<T>, Multiset<T>> { @Override public Supplier<ImmutableMultiset.Builder<T>> supplier() { return ImmutableMultiset::builder; } @Override public BiConsumer<ImmutableMultiset.Builder<T>, T> accumulator() { return ((builder, t) -> builder.add(t)); } @Override public BinaryOperator<ImmutableMultiset.Builder<T>> combiner() { return (a, b) -> { a.addAll(b.build()); return a; }; } @Override public Function<ImmutableMultiset.Builder<T>, Multiset<T>> finisher() { return ImmutableMultiset.Builder::build; } @Override public Set<Characteristics> characteristics() { return EnumSet.of(Characteristics.UNORDERED); } } }