/*
* @(#)SQLInput.java 1.25 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.sql;
/**
* An input stream that contains a stream of values representing an
* instance of an SQL structured type or an SQL distinct type.
* This interface, used only for custom mapping, is used by the driver
* behind the scenes, and a programmer never directly invokes
* <code>SQLInput</code> methods. The <i>reader</i> methods
* (<code>readLong</code>, <code>readBytes</code>, and so on)
* provide a way to read the values in an <code>SQLInput</code> object.
* The method <code>wasNull</code> is used to determine whether the
* the last value read was SQL <code>NULL</code>.
* <P>When the method <code>getObject</code> is called with an
* object of a class implementing the interface <code>SQLData</code>,
* the JDBC driver calls the method <code>SQLData.getSQLType</code>
* to determine the SQL type of the user-defined type (UDT)
* being custom mapped. The driver
* creates an instance of <code>SQLInput</code>, populating it with the
* attributes of the UDT. The driver then passes the input
* stream to the method <code>SQLData.readSQL</code>, which in turn
* calls the <code>SQLInput</code> reader methods
* in its implementation for reading the
* attributes from the input stream.
* @since 1.2
*/
public interface SQLInput {
//================================================================
// Methods for reading attributes from the stream of SQL data.
// These methods correspond to the column-accessor methods of
// java.sql.ResultSet.
//================================================================
/**
* Reads the next attribute in the stream and returns it as a <code>String</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
String readString() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>boolean</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>false</code>
* @exception SQLException if a database access error occurs
*/
boolean readBoolean() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>byte</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code>
* @exception SQLException if a database access error occurs
*/
byte readByte() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>short</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code>
* @exception SQLException if a database access error occurs
*/
short readShort() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as an <code>int</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code>
* @exception SQLException if a database access error occurs
*/
int readInt() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>long</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code>
* @exception SQLException if a database access error occurs
*/
long readLong() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>float</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code>
* @exception SQLException if a database access error occurs
*/
float readFloat() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>double</code>
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>0</code>
* @exception SQLException if a database access error occurs
*/
double readDouble() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>java.math.BigDecimal</code>
* object in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
java.math.BigDecimal readBigDecimal() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as an array of bytes
* in the Java programming language.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
byte[] readBytes() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>java.sql.Date</code> object.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
java.sql.Date readDate() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>java.sql.Time</code> object.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
java.sql.Time readTime() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a <code>java.sql.Timestamp</code> object.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
java.sql.Timestamp readTimestamp() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a stream of Unicode characters.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
java.io.Reader readCharacterStream() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a stream of ASCII characters.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
java.io.InputStream readAsciiStream() throws SQLException;
/**
* Reads the next attribute in the stream and returns it as a stream of uninterpreted
* bytes.
*
* @return the attribute; if the value is SQL <code>NULL</code>, returns <code>null</code>
* @exception SQLException if a database access error occurs
*/
java.io.InputStream readBinaryStream() throws SQLException;
//================================================================
// Methods for reading items of SQL user-defined types from the stream.
//================================================================
/**
* Reads the datum at the head of the stream and returns it as an
* <code>Object</code> in the Java programming language. The
* actual type of the object returned is determined by the default type
* mapping, and any customizations present in this stream's type map.
*
* <P>A type map is registered with the stream by the JDBC driver before the
* stream is passed to the application.
*
* <P>When the datum at the head of the stream is an SQL <code>NULL</code>,
* the method returns <code>null</code>. If the datum is an SQL structured or distinct
* type, it determines the SQL type of the datum at the head of the stream.
* If the stream's type map has an entry for that SQL type, the driver
* constructs an object of the appropriate class and calls the method
* <code>SQLData.readSQL</code> on that object, which reads additional data from the
* stream, using the protocol described for that method.
*
* @return the datum at the head of the stream as an <code>Object</code> in the
* Java programming language;<code>null</code> if the datum is SQL <code>NULL</code>
* @exception SQLException if a database access error occurs
*/
Object readObject() throws SQLException;
/**
* Reads an SQL <code>REF</code> value from the stream and returns it as a
* <code>Ref</code> object in the Java programming language.
*
* @return a <code>Ref</code> object representing the SQL <code>REF</code> value
* at the head of the stream; <code>null</code> if the value read is
* SQL <code>NULL</code>
* @exception SQLException if a database access error occurs
*/
Ref readRef() throws SQLException;
/**
* Reads an SQL <code>BLOB</code> value from the stream and returns it as a
* <code>Blob</code> object in the Java programming language.
*
* @return a <code>Blob</code> object representing data of the SQL <code>BLOB</code> value
* at the head of the stream; <code>null</code> if the value read is
* SQL <code>NULL</code>
* @exception SQLException if a database access error occurs
*/
Blob readBlob() throws SQLException;
/**
* Reads an SQL <code>CLOB</code> value from the stream and returns it as a
* <code>Clob</code> object in the Java programming language.
*
* @return a <code>Clob</code> object representing data of the SQL <code>CLOB</code> value
* at the head of the stream; <code>null</code> if the value read is
* SQL <code>NULL</code>
* @exception SQLException if a database access error occurs
*/
Clob readClob() throws SQLException;
/**
* Reads an SQL <code>ARRAY</code> value from the stream and returns it as an
* <code>Array</code> object in the Java programming language.
*
* @return an <code>Array</code> object representing data of the SQL
* <code>ARRAY</code> value at the head of the stream; <code>null</code>
* if the value read is SQL <code>NULL</code>
* @exception SQLException if a database access error occurs
*/
Array readArray() throws SQLException;
/**
* Retrieves whether the last value read was SQL <code>NULL</code>.
*
* @return <code>true</code> if the most recently read SQL value was SQL
* <code>NULL</code>; <code>false</code> otherwise
* @exception SQLException if a database access error occurs
*
*/
boolean wasNull() throws SQLException;
//---------------------------- JDBC 3.0 -------------------------
/**
* Reads an SQL <code>DATALINK</code> value from the stream and returns it as a
* <code>java.net.URL</code> object in the Java programming language.
*
* @return a <code>java.net.URL</code> object.
* @exception SQLException if a database access error occurs,
* or if a URL is malformed
* @since 1.4
*/
java.net.URL readURL() throws SQLException;
}
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