    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}