001/* 002 * Copyright 2002-2012 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.test.annotation; 018 019import org.springframework.util.Assert; 020 021/** 022 * Implementation of {@link ProfileValueSource} which uses system properties as 023 * the underlying source. 024 * 025 * @author Rod Johnson 026 * @author Sam Brannen 027 * @since 2.0 028 */ 029public class SystemProfileValueSource implements ProfileValueSource { 030 031 private static final SystemProfileValueSource INSTANCE = new SystemProfileValueSource(); 032 033 034 /** 035 * Obtain the canonical instance of this ProfileValueSource. 036 */ 037 public static final SystemProfileValueSource getInstance() { 038 return INSTANCE; 039 } 040 041 042 /** 043 * Private constructor, enforcing the singleton pattern. 044 */ 045 private SystemProfileValueSource() { 046 } 047 048 /** 049 * Get the <em>profile value</em> indicated by the specified key from the 050 * system properties. 051 * @see System#getProperty(String) 052 */ 053 @Override 054 public String get(String key) { 055 Assert.hasText(key, "'key' must not be empty"); 056 return System.getProperty(key); 057 } 058 059}