| /* |
| * 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.interpol; |
| |
| /** |
| * <p> |
| * An enumeration class defining constants for the {@code Lookup} objects |
| * available for each {@code Configuration} object per default. |
| * </p> |
| * <p> |
| * When a new configuration object derived from {@code AbstractConfiguration} is |
| * created it installs a {@link ConfigurationInterpolator} with a default set of |
| * {@link Lookup} objects. These lookups are defined by this enumeration class. |
| * </p> |
| * <p> |
| * All the default {@code Lookup} classes are state-less, thus their instances |
| * can be shared between multiple configuration objects. Therefore, it makes |
| * sense to keep shared instances in this enumeration class. |
| * </p> |
| * |
| * @version $Id$ |
| * @since 2.0 |
| */ |
| public enum DefaultLookups |
| { |
| /** The lookup for system properties. */ |
| SYSTEM_PROPERTIES("sys", new SystemPropertiesLookup()), |
| |
| /** The lookup for environment properties. */ |
| ENVIRONMENT("env", new EnvironmentLookup()), |
| |
| /** The lookup for constants. */ |
| CONST("const", new ConstantLookup()); |
| |
| /** The prefix under which the associated lookup object is registered. */ |
| private final String prefix; |
| |
| /** The associated lookup instance. */ |
| private final Lookup lookup; |
| |
| /** |
| * Creates a new instance of {@code DefaultLookups} and sets the prefix and |
| * the associated lookup instance. |
| * |
| * @param prfx the prefix |
| * @param look the {@code Lookup} instance |
| */ |
| private DefaultLookups(String prfx, Lookup look) |
| { |
| prefix = prfx; |
| lookup = look; |
| } |
| |
| /** |
| * Returns the standard prefix for the lookup object of this kind. |
| * |
| * @return the prefix |
| */ |
| public String getPrefix() |
| { |
| return prefix; |
| } |
| |
| /** |
| * Returns the standard {@code Lookup} instance of this kind. |
| * |
| * @return the associated {@code Lookup} object |
| */ |
| public Lookup getLookup() |
| { |
| return lookup; |
| } |
| } |