/*
 * 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.persistence.strategy.value;

import java.io.Serializable;
import java.security.Principal;

import org.apache.openjpa.jdbc.kernel.JDBCStore;
import org.apache.openjpa.jdbc.meta.ValueMapping;
import org.apache.openjpa.jdbc.meta.strats.AbstractValueHandler;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.schema.ColumnIO;
import org.apache.openjpa.meta.JavaTypes;

/**
 * A ValueHandler which handles a Principal and stores it as String representation.
 * I use Principal because this class exists in every JDK. A more practical example
 * could be joda LocalDate or the new Java8 Date classes.
 */
public class PrincipalValueStrategyHandler extends AbstractValueHandler {

    private static final long serialVersionUID = 8371304701543038775L;

    private static final PrincipalValueStrategyHandler _instance = new PrincipalValueStrategyHandler();

    public static PrincipalValueStrategyHandler getInstance() {
        return _instance;
    }

    @Override
    public Column[] map(ValueMapping arg0, String name, ColumnIO arg2,
                        boolean arg3) {

        Column col = new Column();
        col.setName(name);
        col.setJavaType(JavaTypes.STRING);

        return new Column[]{col};
    }

    public Object toDataStoreValue(ValueMapping vm, Object val, JDBCStore store) {

        if (val instanceof Principal) {
            return ((Principal) val).getName();
        }

        return null;
    }

    public Object toObjectValue(ValueMapping vm, final Object val) {
        if (val == null || !(val instanceof String)) {
            return null;
        }

        return new TestPrincipal((String) val);
    }


    public static class TestPrincipal implements Principal, Serializable {
        private final String name;

        public TestPrincipal(String name) {
            this.name = name;
        }

        @Override
        public String getName() {
            return name;
        }
    }
}