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package org.hsqldb.jdbc;

import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.StringConverter;

import java.io.IOException;
import java.sql.RowId;
import java.sql.SQLException;
import java.util.Arrays;

/* $Id: JDBCRowId.java 5969 2019-04-27 14:59:54Z fredt $ */

//campbell-burnet@users 20060522 - doc 1.8.1 full synch up to Mustang Build 84

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.

Methods in the interfaces ResultSet, CallableStatement,
and PreparedStatement, such as getRowId and setRowId
allow a programmer to access a SQL ROWID  value. The RowId
interface provides a method
for representing the value of the ROWID as a byte array or as a
String.

The method getRowIdLifetime in the interface DatabaseMetaData,
can be used
to determine if a RowId object remains valid for the duration of the transaction in
which  the RowId was created, the duration of the session in which
the RowId 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, getRowIdLifetime specifies the duration of a ROWID
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.

All methods on the RowId interface must be fully implemented if the
JDBC driver supports the data type.
Author:
Campbell Burnet (campbell-burnet@users dot sourceforge.net)
See Also:
DatabaseMetaData
Since:
JDK 1.6, HSQLDB 2.0/**
 *
 * 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 JDK 1.6, HSQLDB 2.0
 * @author Campbell Burnet (campbell-burnet@users dot sourceforge.net)
 */
public final class JDBCRowId implements RowId {

    private int hash;

    // ------------------------- Internal Implementation -----------------------
    private final byte[] id;

    
Constructs a new JDBCRowId instance wrapping the given octet sequence. 

This constructor may be used internally to retrieve result set values as
RowId objects, yet it also may need to be public to allow access from
other packages. As such (in the interest of efficiency) this object
maintains a reference to the given octet sequence rather than making a
copy; special care should be taken by external clients never to use this
constructor with a byte array object that may later be modified
externally.
Params:
id – the octet sequence representing the Rowid value
Throws:
SQLException – if the argument is null/**
     * Constructs a new JDBCRowId instance wrapping the given octet sequence. <p>
     *
     * This constructor may be used internally to retrieve result set values as
     * RowId objects, yet it also may need to be public to allow access from
     * other packages. As such (in the interest of efficiency) this object
     * maintains a reference to the given octet sequence rather than making a
     * copy; special care should be taken by external clients never to use this
     * constructor with a byte array object that may later be modified
     * externally.
     *
     * @param id the octet sequence representing the Rowid value
     * @throws SQLException if the argument is null
     */
    public JDBCRowId(final byte[] id) throws SQLException {

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

    
Constructs a new JDBCRowId instance whose internal octet sequence is
is a copy of the octet sequence of the given RowId object. 

Params:
id – the octet sequence representing the Rowid value
Throws:
SQLException – if the argument is null/**
     * Constructs a new JDBCRowId instance whose internal octet sequence is
     * is a copy of the octet sequence of the given RowId object. <p>
     *
     * @param id the octet sequence representing the Rowid value
     * @throws SQLException if the argument is null
     */
    public JDBCRowId(RowId id) throws SQLException {
        this(id.getBytes());
    }

    
Constructs a new JDBCRowId instance whose internal octet sequence is
is that represented by the given hexadecimal character sequence. 

Params:
hex – the hexadecimal character sequence from which to derive
       the internal octet sequence
Throws:
SQLException – if the argument is null or is not a valid
        hexadecimal character sequence/**
     * Constructs a new JDBCRowId instance whose internal octet sequence is
     * is that represented by the given hexadecimal character sequence. <p>
     * @param hex the hexadecimal character sequence from which to derive
     *        the internal octet sequence
     * @throws java.sql.SQLException if the argument is null or is not a valid
     *         hexadecimal character sequence
     */
    public JDBCRowId(final String hex) throws SQLException {

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

        try {
            this.id = StringConverter.hexStringToByteArray(hex);
        } catch (IOException e) {
            throw JDBCUtil.sqlException(ErrorCode.JDBC_INVALID_ARGUMENT,
                                    "hex: " + e);

            // .illegalHexadecimalCharacterSequenceArgumentException("hex", e);
        }
    }

    
Compares this RowId to the specified object. The result is
true if and only if the argument is not null and is a RowId
object that represents the same ROWID as  this object.

It is important
to consider both the origin and the valid lifetime of a RowId
when comparing it to another RowId. 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.
Params:
obj – the Object to compare this RowId object
    against.
Returns:
true if the RowIds are equal; false otherwise
Since:
JDK 1.6, HSQLDB 2.0/**
     * 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 JDK 1.6, HSQLDB 2.0
     */
    public boolean equals(Object obj) {
        return (obj instanceof JDBCRowId)
               && Arrays.equals(this.id, ((JDBCRowId) obj).id);
    }

    
Returns an array of bytes representing the value of the SQL ROWID
designated by this java.sql.RowId object.
Returns:
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./**
     * 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.
     */
    public byte[] getBytes() {
        return id.clone();
    }

    
Returns a String representing the value of the SQL ROWID designated by this
java.sql.RowId object.

Like java.sql.Date.toString()
returns the contents of its DATE as the String "2004-03-17"
rather than as  DATE literal in SQL (which would have been the String
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 ROWID literal.
Returns:
a String whose format is determined by the driver supplying the
    connection, representing the value of the ROWID designated
    by this java.sql.RowId  object./**
     * 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.
     */
    public String toString() {
        return StringConverter.byteArrayToHexString(id);
    }

    
Returns a hash code value of this RowId object.
Returns:
a hash code for the RowId/**
     * Returns a hash code value of this <code>RowId</code> object.
     *
     * @return a hash code for the <code>RowId</code>
     */
    public int hashCode() {

        if (hash == 0) {
            hash = Arrays.hashCode(id);
        }

        return hash;
    }

    
Direct access to id bytes for subclassing.
Returns:
direct reference to id bytes./**
     * Direct access to id bytes for subclassing.
     *
     * @return direct reference to id bytes.
     */
    Object id() {
        return id;
    }
}