| /* |
| * 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.jackrabbit.oak.composite; |
| |
| import org.apache.jackrabbit.guava.common.collect.ImmutableMap; |
| import org.apache.jackrabbit.oak.spi.mount.Mount; |
| |
| import java.util.Map; |
| import java.util.function.BiFunction; |
| import java.util.function.Function; |
| import java.util.function.Supplier; |
| |
| public class NodeMap<T> { |
| |
| private final Map<MountedNodeStore, CacheableSupplier<T>> suppliers; |
| |
| private NodeMap(Map<MountedNodeStore, CacheableSupplier<T>> suppliers) { |
| this.suppliers = suppliers; |
| } |
| |
| public static <T> NodeMap<T> create(Map<MountedNodeStore, T> nodes) { |
| ImmutableMap.Builder<MountedNodeStore, CacheableSupplier<T>> suppliers = ImmutableMap.builder(); |
| nodes.forEach((mns, node) -> suppliers.put(mns, new CacheableSupplier<T>(node))); |
| return new NodeMap<>(suppliers.build()); |
| } |
| |
| public T get(MountedNodeStore nodeStore) { |
| if (!suppliers.containsKey(nodeStore)) { |
| Mount mount = nodeStore.getMount(); |
| String mountName = mount.isDefault() ? "[default]" : mount.getName(); |
| throw new IllegalStateException("Node is not available for the node store " + mountName); |
| } |
| return suppliers.get(nodeStore).get(); |
| } |
| |
| public <R> NodeMap<R> getAndApply(BiFunction<MountedNodeStore, T, R> function) { |
| ImmutableMap.Builder<MountedNodeStore, CacheableSupplier<R>> newSuppliers = ImmutableMap.builder(); |
| suppliers.forEach((mns, node) -> newSuppliers.put(mns, node.getAndApply(curry(function, mns)))); |
| return new NodeMap<>(newSuppliers.build()); |
| } |
| |
| public <R> NodeMap<R> lazyApply(BiFunction<MountedNodeStore, T, R> function) { |
| ImmutableMap.Builder<MountedNodeStore, CacheableSupplier<R>> newSuppliers = ImmutableMap.builder(); |
| suppliers.forEach((mns, node) -> newSuppliers.put(mns, node.lazyApply(curry(function, mns)))); |
| return new NodeMap<>(newSuppliers.build()); |
| } |
| |
| private static <T, U, R> Function<U, R> curry(BiFunction<T, U, R> function, T value) { |
| return u -> function.apply(value, u); |
| } |
| |
| public NodeMap<T> replaceNode(MountedNodeStore nodeStore, T node) { |
| ImmutableMap.Builder<MountedNodeStore, CacheableSupplier<T>> newSuppliers = ImmutableMap.builder(); |
| suppliers.forEach((mns, n) -> { |
| if (mns != nodeStore) { |
| newSuppliers.put(mns, n); |
| } |
| }); |
| newSuppliers.put(nodeStore, new CacheableSupplier<>(node)); |
| return new NodeMap<>(newSuppliers.build()); |
| } |
| |
| private static class CacheableSupplier<T> implements Supplier<T> { |
| |
| private Supplier<T> supplier; |
| |
| private volatile T value; |
| |
| private CacheableSupplier(Supplier<T> supplier) { |
| this.supplier = supplier; |
| } |
| |
| public CacheableSupplier(T value) { |
| this.value = value; |
| } |
| |
| @Override |
| public T get() { |
| if (value == null) { |
| synchronized (this) { |
| if (value == null) { |
| value = supplier.get(); |
| supplier = null; |
| } |
| } |
| } |
| return value; |
| } |
| |
| public <R> CacheableSupplier<R> getAndApply(Function<T, R> function) { |
| return new CacheableSupplier<>(function.apply(get())); |
| } |
| |
| public <R> CacheableSupplier<R> lazyApply(Function<T, R> function) { |
| return new CacheableSupplier<>(() -> function.apply(get())); |
| } |
| } |
| } |