| /* |
| * 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.commons.configuration2; |
| |
| import org.apache.commons.configuration2.interpol.Lookup; |
| |
| /** |
| * <p> |
| * A specialized implementation of the {@code Lookup} interface which uses a {@code Configuration} object to resolve |
| * variables. |
| * </p> |
| * <p> |
| * This class is passed an {@link ImmutableConfiguration} object at construction time. In its implementation of the |
| * {@code lookup()} method it simply queries this configuration for the passed in variable name. So the keys passed to |
| * {@code lookup()} are mapped directly to configuration properties. |
| * </p> |
| * |
| * @since 2.0 |
| */ |
| public class ConfigurationLookup implements Lookup { |
| /** The configuration to which lookups are delegated. */ |
| private final ImmutableConfiguration configuration; |
| |
| /** |
| * Creates a new instance of {@code ConfigurationLookup} and sets the associated {@code ImmutableConfiguration}. |
| * |
| * @param config the configuration to use for lookups (must not be <b>null</b>) |
| * @throws IllegalArgumentException if the configuration is <b>null</b> |
| */ |
| public ConfigurationLookup(final ImmutableConfiguration config) { |
| if (config == null) { |
| throw new IllegalArgumentException("Configuration must not be null!"); |
| } |
| configuration = config; |
| } |
| |
| /** |
| * Gets the {@code ImmutableConfiguration} used by this object. |
| * |
| * @return the associated {@code ImmutableConfiguration} |
| */ |
| public ImmutableConfiguration getConfiguration() { |
| return configuration; |
| } |
| |
| /** |
| * {@inheritDoc} This implementation calls {@code getProperty()} on the associated configuration. The return value is |
| * directly returned. Note that this may be a complex object, e.g. a collection or an array. |
| */ |
| @Override |
| public Object lookup(final String variable) { |
| return getConfiguration().getProperty(variable); |
| } |
| } |