Java tutorial
/* * Copyright (c) 2016, Stein Eldar Johnsen * * 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 net.morimekta.config.impl; import net.morimekta.config.Config; import net.morimekta.config.util.ConfigUtil; import com.google.common.collect.ImmutableMap; import java.util.Map; import java.util.Set; import java.util.function.Supplier; import java.util.stream.Collectors; /** * A config mapped onto different keys. */ public class MappedConfig implements Config { private final ImmutableMap<String, String> mapping; private final Supplier<Config> contained; public MappedConfig(Supplier<Config> contained, Map<String, String> mapping) { this.contained = contained; this.mapping = ImmutableMap.copyOf(mapping); } @Override public Object get(String key) { if (!mapping.containsKey(key)) { return null; } return contained.get().get(mapping.get(key)); } @Override public boolean containsKey(String key) { if (!mapping.containsKey(key)) { return false; } return contained.get().containsKey(mapping.get(key)); } @Override public Set<String> keySet() { return mapping.keySet().stream().filter(this::containsKey).collect(Collectors.toSet()); } @Override public boolean equals(Object o) { if (o == this) { return true; } else if (o == null || !(o instanceof Config)) { return false; } return ConfigUtil.equals(this, (Config) o); } @Override public int hashCode() { return ConfigUtil.hashCode(this); } @Override public String toString() { return ConfigUtil.toString(this); } }