    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    }