| /* |
| * 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.wayang.core.api.configuration; |
| |
| import org.apache.commons.lang3.Validate; |
| import org.apache.wayang.core.api.Configuration; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * Implementation of {@link KeyValueProvider} that uses a {@link Map} to provide a value. |
| */ |
| public class MapBasedKeyValueProvider<Key, Value> extends KeyValueProvider<Key, Value> { |
| |
| private final Map<Key, Value> storedValues = new HashMap<>(); |
| |
| private final boolean isCaching; |
| |
| /** |
| * Creates a new caching instance. |
| */ |
| public MapBasedKeyValueProvider(KeyValueProvider<Key, Value> parent) { |
| this(parent, true); |
| } |
| |
| /** |
| * Creates a new caching instance. |
| */ |
| public MapBasedKeyValueProvider(KeyValueProvider<Key, Value> parent, Configuration configuration) { |
| this(parent, configuration, true); |
| } |
| |
| /** |
| * Creates a new instance. |
| * |
| * @param isCaching if, when a value is provided by the {@code parent}, that value should be cached in the new instance |
| */ |
| public MapBasedKeyValueProvider(KeyValueProvider<Key, Value> parent, boolean isCaching) { |
| super(parent); |
| this.isCaching = isCaching; |
| } |
| |
| |
| /** |
| * Creates a new instance. |
| * |
| * @param isCaching if, when a value is provided by the {@code parent}, that value should be cached in the new instance |
| */ |
| public MapBasedKeyValueProvider(Configuration configuration, boolean isCaching) { |
| super(null, configuration); |
| this.isCaching = isCaching; |
| } |
| |
| /** |
| * Creates a new instance. |
| */ |
| public MapBasedKeyValueProvider(KeyValueProvider<Key, Value> parent, Configuration configuration, boolean isCaching) { |
| super(parent, configuration); |
| this.isCaching = isCaching; |
| } |
| |
| @Override |
| public Value tryToProvide(Key key, KeyValueProvider<Key, Value> requestee) { |
| Validate.notNull(key); |
| return this.storedValues.get(key); |
| } |
| |
| @Override |
| protected void processParentEntry(Key key, Value value) { |
| super.processParentEntry(key, value); |
| if (this.isCaching && value != null) { |
| this.storedValues.putIfAbsent(key, value); |
| } |
| } |
| |
| @Override |
| public void set(Key key, Value value) { |
| Validate.notNull(key); |
| this.storedValues.put(key, value); |
| } |
| |
| } |