001/* -*- mode: Java; c-basic-offset: 2; indent-tabs-mode: nil; coding: utf-8-unix -*- 002 * 003 * Copyright © 2017-2018 microBean. 004 * 005 * Licensed under the Apache License, Version 2.0 (the "License"); 006 * you may not use this file except in compliance with the License. 007 * You may obtain a copy of the License at 008 * 009 * http://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 014 * implied. See the License for the specific language governing 015 * permissions and limitations under the License. 016 */ 017package org.microbean.configuration.spi; 018 019import java.io.Serializable; 020 021import java.util.Collections; 022import java.util.Map; 023import java.util.Set; 024 025import org.microbean.configuration.Configurations; 026 027import org.microbean.configuration.api.ConfigurationValue; 028 029/** 030 * An {@link AbstractConfiguration} conceptually housing only the 031 * configuration property that returns a {@link Map}-convertible 032 * {@link String} representing configuration coordinates for the 033 * calling application. 034 * 035 * @author <a href="https://about.me/lairdnelson" 036 * target="_parent">Laird Nelson</a> 037 * 038 * @see Configurations#getConfigurationCoordinates() 039 */ 040public final class ConfigurationCoordinates extends AbstractConfiguration implements Serializable { 041 042 043 /* 044 * Static fields. 045 */ 046 047 048 /** 049 * The version of this class for {@linkplain Serializable 050 * serialization} purposes. 051 */ 052 private static final long serialVersionUID = 1L; 053 054 055 /* 056 * Constructors. 057 */ 058 059 060 /** 061 * Creates a new {@link ConfigurationCoordinates}. 062 */ 063 public ConfigurationCoordinates() { 064 super(); 065 } 066 067 068 /* 069 * Instance methods. 070 */ 071 072 073 /** 074 * Attempts to return a value for the {@linkplain 075 * System#getProperty(String, String) System property} named {@value 076 * org.microbean.configuration.Configurations#CONFIGURATION_COORDINATES}. 077 * 078 * <p>This method may return {@code null}.</p> 079 * 080 * @param ignoredConfigurationCoordinates a {@link Map} of 081 * configuration coordinates in effect for the request; effectively 082 * ignored since by definition this method will be returning a 083 * {@link ConfigurationValue} {@linkplain 084 * ConfigurationValue#getValue() containing} a {@link String} value 085 * representing a {@link Map} of configuration coordinates for the 086 * caller; may be {@code null}; not used by this implementation 087 * 088 * @param name the name of the configuration property for which a 089 * value should be returned; may be {@code null} 090 * 091 * @return a {@link ConfigurationValue} representing the 092 * configuration coordinates to assign to the caller, or {@code 093 * null} 094 */ 095 @Override 096 public final ConfigurationValue getValue(final Map<String, String> ignoredConfigurationCoordinates, final String name) { 097 ConfigurationValue returnValue = null; 098 if (Configurations.CONFIGURATION_COORDINATES.equals(name)) { 099 final String configurationCoordinates = System.getProperty(Configurations.CONFIGURATION_COORDINATES); 100 if (configurationCoordinates != null) { 101 returnValue = new ConfigurationValue(this, null, name, configurationCoordinates, true); 102 } 103 } 104 return returnValue; 105 } 106 107 /** 108 * Returns a {@link Set} of the names of all {@link 109 * ConfigurationValue}s that might be returned by this {@link 110 * Configuration}. 111 * 112 * <p>This method never returns {@code null}.</p> 113 * 114 * <p>This implementation returns a {@link Set} with only the value 115 * of {@link Configurations#CONFIGURATION_COORDINATES} in it.</p> 116 * 117 * @return a non-{@code null} {@link Set} of names 118 */ 119 public final Set<String> getNames() { 120 return Collections.singleton(Configurations.CONFIGURATION_COORDINATES); 121 } 122 123}