001    // Copyright 2006 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry5.ioc.internal.services;
016    
017    import org.apache.tapestry5.ioc.services.SymbolProvider;
018    
019    /**
020     * Obtains symbol values from JVM System properties. This implementation is usually ordered first, so that explicit
021     * overrides, provided as JVM system properties, can take effect.
022     */
023    public class SystemPropertiesSymbolProvider implements SymbolProvider
024    {
025        public String valueForSymbol(String symbolName)
026        {
027            return System.getProperty(symbolName);
028        }
029    }