idgenerator.java

torque服务器源代码

package org.apache.torque.oid;

/* ====================================================================
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 * reserved.
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 *    if and wherever such third-party acknowledgments normally appear.
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import java.sql.Connection;
import java.math.BigDecimal;

/**
 * Interface to be implemented by id generators.  It is possible
 * that some implementations might not require all the arguments,
 * for example MySQL will not require a keyInfo Object, while the
 * IDBroker implementation does not require a Connection as
 * it only rarely needs one and retrieves a connection from the
 * Connection pool service only when needed.
 *
 * @author <a href="mailto:[e-mail]">John D. McNally</a>
 * @version $Id: IdGenerator.java,v 1.7 2002/05/07 17:13:22 mpoeschl Exp $
 */
public interface IdGenerator
{
    /**
     * Returns an id as a primitive int.  If you use numeric
     * identifiers, it's suggested that {@link
     * #getIdAsLong(Connection, Object)} be used instead (due to the
     * limitted range of this method).
     *
     * @param connection A Connection.
     * @param keyInfo an Object that contains additional info.
     * @return An int with the value for the id.
     * @exception Exception Database error.
     */
    int getIdAsInt(Connection connection, Object keyInfo)
        throws Exception;

    /**
     * Returns an id as a primitive long.
     *
     * @param connection A Connection.
     * @param keyInfo an Object that contains additional info.
     * @return A long with the value for the id.
     * @exception Exception Database error.
     */
    long getIdAsLong(Connection connection, Object keyInfo)
        throws Exception;

    /**
     * Returns an id as a BigDecimal.
     *
     * @param connection A Connection.
     * @param keyInfo an Object that contains additional info.
     * @return A BigDecimal id.
     * @exception Exception Database error.
     */
    BigDecimal getIdAsBigDecimal(Connection connection, Object keyInfo)
        throws Exception;

    /**
     * Returns an id as a String.
     *
     * @param connection A Connection.
     * @param keyInfo an Object that contains additional info.
     * @return A String id
     * @exception Exception Database error.
     */
    String getIdAsString(Connection connection, Object keyInfo)
        throws Exception;

    /**
     * A flag to determine the timing of the id generation
     *
     * @return a <code>boolean</code> value
     */
    boolean isPriorToInsert();

    /**
     * A flag to determine the timing of the id generation
     *
     * @return Whether id is availble post-<code>insert</code>.
     */
    boolean isPostInsert();

    /**
     * A flag to determine whether a Connection is required to
     * generate an id.
     *
     * @return a <code>boolean</code> value
     */
    boolean isConnectionRequired();
}