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/*
 * 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 com.arakelian.jdbc.handler;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.HashSet;
import java.util.Set;

public class SetHandler implements ResultSetHandler> {
    /**
     * Row handler
     */
    private final ResultSetHandler rowHandler;

    public SetHandler(final ResultSetHandler rowHandler) {
        if (rowHandler == null) {
            throw new IllegalArgumentException();
        }
        this.rowHandler = rowHandler;
    }

    public final ResultSetHandler getRowHandler() {
        return rowHandler;
    }

    /**
     * Whole ResultSet handler. It produce Set as result. To convert
     * individual rows into Java objects it uses the rowHandler.
     *
     * @param rs
     *            ResultSet to process.
     * @return a list of all rows in the result set
     * @throws SQLException
     *             error occurs
     */
    @Override
    public Set handle(final ResultSet rs, final ResultSetMetaData rsmd) throws SQLException {
        final Set result = createList();
        for (;;) {
            final T row = rowHandler.handle(rs, rsmd);
            if (rowHandler.wasLast(row)) {
                break;
            }
            result.add(row);
        }
        return result;
    }

    @Override
    public boolean wasLast(final Set result) {
        // handle method always exhausts ResultSet
        return true;
    }

    protected Set createList() {
        return new HashSet<>();
    }
}