/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * 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,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.openjpa.lib.conf;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.apache.openjpa.lib.log.Log;
import org.apache.openjpa.lib.util.Localizer;

/**
 * Simple configuration provider that sets configuration based on a
 * provided map.
 *
 * @author Abe White
 */
public class MapConfigurationProvider implements ConfigurationProvider {

    private static final Localizer _loc = Localizer.forPackage
        (MapConfigurationProvider.class);

    private Map _props = null;

    /**
     * Construct with null properties.
     */
    public MapConfigurationProvider() {
    }

    /**
     * Constructor; supply properties map.
     */
    public MapConfigurationProvider(Map props) {
        addProperties(props);
    }

    @Override
    public Map getProperties() {
        return (_props == null) ? Collections.EMPTY_MAP : _props;
    }

    @Override
    public void addProperties(Map props) {
        if (props == null || props.isEmpty())
            return;
        if (_props == null)
            _props = new HashMap();
        _props.putAll(props);
    }

    @Override
    public Object addProperty(String key, Object value) {
        if (_props == null)
            _props = new HashMap();
        return _props.put(key, value);
    }

    @Override
    public void setInto(Configuration conf) {
        setInto(conf, conf.getConfigurationLog());
    }

    /**
     * Set properties into configuration. If the log is non-null, will log
     * a TRACE message about the set.
     */
    protected void setInto(Configuration conf, Log log) {
        if (log != null && log.isTraceEnabled())
            log.trace(_loc.get("conf-load", getProperties()));
        if (_props != null)
            conf.fromProperties(_props);
    }
}
