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 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
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 *  KIND, either express or implied.  See the License for the
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package org.apache.cayenne.access;

import java.util.Map;

import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.Persistent;
import org.apache.cayenne.configuration.Constants;
import org.apache.cayenne.configuration.RuntimeProperties;
import org.apache.cayenne.di.Inject;
import org.apache.commons.collections.map.AbstractReferenceMap;
import org.apache.commons.collections.map.ReferenceMap;

/**
 * Default implementation of {@link ObjectMapRetainStrategy}.
 * 
 * @since 3.1
 */
public class DefaultObjectMapRetainStrategy implements ObjectMapRetainStrategy {

    private static final String WEAK_RETAIN_STRATEGY = "weak";
    private static final String SOFT_RETAIN_STRATEGY = "soft";
    private static final String HARD_RETAIN_STRATEGY = "hard";

    protected RuntimeProperties runtimeProperties;

    public DefaultObjectMapRetainStrategy(@Inject RuntimeProperties runtimeProperties) {
        this.runtimeProperties = runtimeProperties;
    }

    @SuppressWarnings("unchecked")
    public Map<Object, Persistent> createObjectMap() {
        String strategy = runtimeProperties
                .get(Constants.SERVER_OBJECT_RETAIN_STRATEGY_PROPERTY);

        if (strategy == null || WEAK_RETAIN_STRATEGY.equals(strategy)) {
            return new ReferenceMap(AbstractReferenceMap.HARD, AbstractReferenceMap.WEAK);
        } else if (SOFT_RETAIN_STRATEGY.equals(strategy)) {
            return new ReferenceMap(AbstractReferenceMap.HARD, AbstractReferenceMap.SOFT);
        } else if (HARD_RETAIN_STRATEGY.equals(strategy)) {
            return new ReferenceMap(AbstractReferenceMap.HARD, AbstractReferenceMap.HARD);
        } else {
            throw new CayenneRuntimeException("Unsupported retain strategy %s", strategy);
        }
    }
}