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
015package org.apache.tapestry5.ioc.internal;
016
017import org.apache.tapestry5.ioc.def.ContributionDef;
018
019import java.util.Map;
020
021public 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}