/*
 * @(#)RowId.java	1.5 06/05/28
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.sql;
 
/**
 * 
 * The representation (mapping) in the Java programming language of an SQL ROWID
 * value. An SQL ROWID is a built-in type, a value of which can be thought of as
 * an address  for its identified row in a database table. Whether that address
 * is logical or, in any  respects, physical is determined by its originating data 
 * source.  
 * <p>
 * Methods in the interfaces <code>ResultSet</code>, <code>CallableStatement</code>,
 * and <code>PreparedStatement</code>, such as <code>getRowId</code> and <code>setRowId</code>
 * allow a programmer to access a SQL <code>ROWID</code>  value. The <code>RowId</code>
 * interface provides a method 
 * for representing the value of the <code>ROWID</code> as a byte array or as a 
 * <code>String</code>. 
 * <p>
 * The method <code>getRowIdLifetime</code> in the interface <code>DatabaseMetaData</code>,
 * can be used 
 * to determine if a <code>RowId</code> object remains valid for the duration of the transaction in 
 * which  the <code>RowId</code> was created, the duration of the session in which 
 * the <code>RowId</code> was created,
 * or, effectively, for as long as its identified row is not deleted. In addition
 * to specifying the duration of its valid lifetime outside its originating data
 * source, <code>getRowIdLifetime</code> specifies the duration of a <code>ROWID</code>
 * value's valid lifetime 
 * within its originating data source. In this, it differs from a large object,
 * because there is no limit on the valid lifetime of a large  object within its 
 * originating data source.  
 * <p>
 * All methods on the <code>RowId</code> interface must be fully implemented if the 
 * JDBC driver supports the data type.
 *
 * @see java.sql.DatabaseMetaData
 * @since 1.6
 */

public interface RowId {
    /**
     * Compares this <code>RowId</code> to the specified object. The result is 
     * <code>true</code> if and only if the argument is not null and is a RowId 
     * object that represents the same ROWID as  this object. 
     * <p>
     * It is important 
     * to consider both the origin and the valid lifetime of a <code>RowId</code>
     * when comparing it to another <code>RowId</code>. If both are valid, and 
     * both are from the same table on the same data source, then if they are equal
     * they identify 
     * the same row; if one or more is no longer guaranteed to be valid, or if 
     * they originate from different data sources, or different tables on the
     * same data source, they  may be equal but still
     * not identify the same row. 
     * 
     * @param obj the <code>Object</code> to compare this <code>RowId</code> object
     *     against.
     * @return true if the <code>RowId</code>s are equal; false otherwise
     * @since 1.6
     */
    boolean equals(Object obj);
    
    /** 
     * Returns an array of bytes representing the value of the SQL <code>ROWID</code>
     * designated by this <code>java.sql.RowId</code> object.
     * 
     * @return an array of bytes, whose length is determined by the driver supplying
     *     the connection, representing the value of the ROWID designated by this
     *     java.sql.RowId object.  
     */
     byte[] getBytes();
     
     /**
      * Returns a String representing the value of the SQL ROWID designated by this
      * <code>java.sql.RowId</code> object.
      * <p>
      *Like <code>java.sql.Date.toString()</code>
      * returns the contents of its DATE as the <code>String</code> "2004-03-17" 
      * rather than as  DATE literal in SQL (which would have been the <code>String</code>
      * DATE "2004-03-17"), toString() 
      * returns the contents of its ROWID in a form specific to the driver supplying 
      * the connection, and possibly not as a <code>ROWID</code> literal. 
      * 
      * @return a String whose format is determined by the driver supplying the 
      *     connection, representing the value of the <code>ROWID</code> designated
      *     by this <code>java.sql.RowId</code>  object. 
      */
     String toString();
     
     /**
      * Returns a hash code value of this <code>RowId</code> object.
      *
      * @return a hash code for the <code>RowId</code>
      */
     int hashCode();

}