    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *     https://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.configuration2.interpol;
    018
    019import org.apache.commons.text.lookup.StringLookupFactory;
    020
    021/**
    022 * <p>
    023 * A specialized implementation of the {@code Lookup} interface that allows access to system properties.
    024 * </p>
    025 * <p>
    026 * This implementation relies on {@code StrLookup.systemPropertiesLookup()} from the Commons Lang project to resolve
    027 * system properties. It can be used for referencing system properties in configuration files in an easy way, for
    028 * instance:
    029 * </p>
    030 *
    031 * <pre>
    032 * current.user = ${sys:user.name}
    033 * </pre>
    034 *
    035 * <p>
    036 * {@code SystemPropertiesLookup} is one of the standard lookups that is registered per default for each configuration.
    037 * </p>
    038 *
    039 * @since 2.0
    040 * @deprecated Use {@link DefaultLookups#SYSTEM_PROPERTIES}.
    041 */
    042@Deprecated
    043public class SystemPropertiesLookup implements Lookup {
    044    @Override
    045    public Object lookup(final String variable) {
    046        return StringLookupFactory.INSTANCE.systemPropertyStringLookup().lookup(variable);
    047    }
    048}