001    // Copyright 2009 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;
016    
017    import org.apache.tapestry5.ioc.def.ContributionDef;
018    
019    import java.util.Map;
020    
021    public class MappedConfigurationOverride<K, V>
022    {
023        private final Map<K, V> configuration;
024    
025        private final K key;
026    
027        private final V overrideValue;
028    
029        private final ContributionDef contribDef;
030    
031        public MappedConfigurationOverride(ContributionDef contribDef, Map<K, V> configuration, K key, V overrideValue)
032        {
033            this.contribDef = contribDef;
034            this.configuration = configuration;
035            this.key = key;
036            this.overrideValue = overrideValue;
037        }
038    
039        void apply()
040        {
041            if (!configuration.containsKey(key))
042                throw new IllegalArgumentException(
043                        String.format("Override for key %s (at %s) does not match an existing key.", key, contribDef));
044    
045            if (overrideValue == null)
046                configuration.remove(key);
047            else
048                configuration.put(key, overrideValue);
049        }
050    
051        public ContributionDef getContribDef()
052        {
053            return contribDef;
054        }
055    }