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 *
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 *
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package org.hsqldb.jdbc;

import java.sql.SQLException;
import java.sql.Savepoint;

/**
 * The representation of a savepoint, which is a point within
 * the current transaction that can be referenced from the
 * {@code Connection.rollback} method. When a transaction
 * is rolled back to a savepoint all changes made after that
 * savepoint are undone.
 * <p>
 * Savepoints can be either named or unnamed. Unnamed savepoints
 * are identified by an ID generated by the underlying data source.
 *
 * <!-- start Release-specific documentation -->
 * <div class="ReleaseSpecificDocumentation">
 * <p class="rshead">HSQLDB-Specific Information:</p>
 *
 * SQL 2003 standard does not support unnamed savepoints. However, this
 * feature is supported from version 2.0.<p>
 *
 * If the connection is autoCommit, setting savepoints has no effect as any
 * such savepoint is cleared upon the execution of the first transactional
 * statement.
 *
 * </div>
 * <!-- end release-specific documentation -->
 *
 * @author Campbell Burnet (campbell-burnet@users dot sourceforge.net)
 * @since JDK 1.4, HSQLDB 1.7.2
 */
public class JDBCSavepoint implements Savepoint {

    int            id;
    String         name;
    JDBCConnection connection;

    JDBCSavepoint(String name, JDBCConnection conn) throws SQLException {

        if (name == null) {
            throw JDBCUtil.nullArgument("name");
        }

        if (conn == null) {
            throw JDBCUtil.nullArgument("conn");
        }

        this.name       = name;
        this.id         = -1;
        this.connection = conn;
    }

    JDBCSavepoint(JDBCConnection conn) throws SQLException {

        if (conn == null) {
            throw JDBCUtil.nullArgument("conn");
        }

        this.id         = conn.getSavepointID();
        this.name       = "SYSTEM_SAVEPOINT_" + id;
        this.connection = conn;
    }

    /**
     * Retrieves the generated ID for the savepoint that this
     * {@code Savepoint} object represents.
     * @return the numeric ID of this savepoint
     * @throws SQLException if this is a named savepoint
     * @since 1.4
     */
    public int getSavepointId() throws SQLException {

        if (id != -1) {
            return id;
        }

        throw JDBCUtil.notSupported();
    }

    /**
     * Retrieves the name of the savepoint that this {@code Savepoint}
     * object represents.
     * @return the name of this savepoint
     * @throws SQLException if this is an un-named savepoint
     * @since 1.4
     */
    public String getSavepointName() throws SQLException {

        if (id == -1) {
            return name;
        }

        throw JDBCUtil.notSupported();
    }

    public String toString() {
        return super.toString() + "[name=" + name + "]";
    }
}
