org.skife.jdbi.v2.ResultSetResultIterator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jdbi Show documentation

jDBI is designed to provide convenient tabular data access in Java(tm). It uses the Java collections framework for query results, provides a convenient means of externalizing sql statements, and provides named parameter support for any database being used.

There is a newer version: 2.78

Show newest version

/*
 * Licensed 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.skife.jdbi.v2;

import org.skife.jdbi.v2.exceptions.ResultSetException;
import org.skife.jdbi.v2.tweak.ResultSetMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

class ResultSetResultIterator implements ResultIterator
{
    private final ResultSetMapper mapper;
    private final SQLStatement jdbiStatement;
    private final ResultSet results;
    private final StatementContext context;

    private volatile boolean alreadyAdvanced = false;
    private volatile int count = 0;
    private volatile boolean hasNext = false;
    private volatile boolean closed = false;

    ResultSetResultIterator(ResultSetMapper mapper,
                            SQLStatement jdbiStatement,
                            Statement stmt,
                            StatementContext context)
            throws SQLException
    {
        this.mapper = mapper;
        this.context = context;
        this.jdbiStatement = jdbiStatement;
        this.results = stmt.getResultSet();

        this.jdbiStatement.addCleanable(Cleanables.forResultSet(results));
    }

    @Override
    public void close()
    {
        if (closed) {
            return;
        }
        closed = true;
        jdbiStatement.cleanup();
    }

    @Override
    public boolean hasNext()
    {
        if (closed) {
            return false;
        }

        if (alreadyAdvanced) {
            return hasNext;
        }

        hasNext = safeNext();

        if (hasNext) {
            alreadyAdvanced = true;
        }
        else {
            close();
        }

        return hasNext;
    }

    @Override
    public Type next()
    {
        if (closed) {
            throw new IllegalStateException("iterator is closed");
        }

        if (!hasNext()) {
            close();
            throw new IllegalStateException("No element to advance to");
        }

        try {
            return mapper.map(count++, results, context);
        }
        catch (SQLException e) {
            throw new ResultSetException("Error thrown mapping result set into return type", e, context);
        }
        finally {
            alreadyAdvanced = safeNext();
            if (!alreadyAdvanced) {
                close();
            }
        }
    }

    @Override
    public void remove()
    {
        throw new UnsupportedOperationException("Deleting from a result set iterator is not yet supported");
    }

    private boolean safeNext()
    {
        try {
            return results.next();
        }
        catch (SQLException e) {
            throw new ResultSetException("Unable to advance result set", e, context);
        }
    }
}