WebLogic Server 5.1.0 API Reference

weblogic.db.jdbc
Class DataSet

java.lang.Object
  |
  +--weblogic.db.jdbc.DataSet

Direct Known Subclasses:

QueryDataSet, TableDataSet

public abstract class DataSet

extends java.lang.Object

implements WLSerializable

DataSet is the abstract parent class of TableDataSet and QueryDataSet. A DataSet manages record caching details.

Each DataSet is bound to a Schema, which holds metadata such as the name, datatype, and size of each record in the DataSet. Records in a DataSet are accessible by index position (0-based).

For implementation and usage, see the Developers Guide and tutorials.

Author:

Copyright (c) 1995-1998 by WebLogic, Inc. All Rights Reserved., Copyright (c) 1998-1999 by BEA Systems, Inc. All Rights Reserved.
Copyright © 2000 BEA Systems, Inc. All Rights Reserved.

See Also:

Record, Schema, QueryDataSet, TableDataSet, Serialized Form

Field Summary

protected boolean	cached
protected boolean	resetable
protected java.sql.ResultSet	resultval
protected java.sql.Statement	stmt

Constructor Summary

DataSet()
Internal use only.

Method Summary

Record	addRecord() Adds a new Record to a DataSet.
boolean	allRecordsRetrieved() Determines whether all records for a DataSet have been retrieved.
DataSet	clearRecords() Clears all Records from a DataSet.
void	close() Closes all the resources associated with a DataSet.
java.sql.Connection	connection() Returns the Connection object of a DataSet.
boolean	containsRecord(int pos) Determines whether a Record exists at the specified position.
void	destroy() Internal use only.
DataSet	fetchRecords() Fetches all records.
DataSet	fetchRecords(int maxrecs) Fetches at most the specified number of records.
DataSet	fetchRecords(int start, int maxrecs) Fetches at most the specified number of records starting at the specified record.
Record	getRecord(int pos) Gets a Record at the specified 0-based index position in a DataSet.
java.sql.ResultSet	getResultSet() Gets the java.sql.ResultSet used to create a DataSet.
abstract java.lang.String	getSelectString() Gets the SelectStatement associated with a DataSet.
void	initialize() Internal use only.
int	lastFetchSize() Returns the number of records fetched in the previous fetch action.
int[]	maxColumnWidths(boolean with_heading) Calculates the maximum widths of the columns in a DataSet.
void	readObject(WLObjectInput sis) Internal use only.
DataSet	releaseRecords() Closes the DataSet and releases all Records from it but does not nullify them.
Record	removeRecord(Record rec) Removes the specified Record object from a DataSet.
DataSet	reset() Clears the current contents of a DataSet.
abstract java.sql.ResultSet	resultSet() Returns the java.sql.ResultSet associated with a DataSet.
Schema	schema() Returns the Schema object of a DataSet.
int	size() Returns the number of Records in a DataSet.
java.lang.String	toString() Returns the string representation of all the Records of a DataSet.
void	writeObject(WLObjectOutput sos) Internal use only.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

resetable

protected boolean resetable

cached

protected boolean cached

stmt

protected transient java.sql.Statement stmt

resultval

protected transient java.sql.ResultSet resultval

Constructor Detail

DataSet

public DataSet()

Internal use only.

Method Detail

resultSet

public abstract java.sql.ResultSet resultSet()
                                      throws java.sql.SQLException,
                                             DataSetException

Returns the java.sql.ResultSet associated with a DataSet.

Returns:

JDBC ResultSet

Throws:

java.sql.SQLException - if there is a SQL error

DataSetException - if there is a data error

getResultSet

public java.sql.ResultSet getResultSet()

Gets the java.sql.ResultSet used to create a DataSet.

Returns:

JDBC ResultSet

connection

public java.sql.Connection connection()

Returns the Connection object of a DataSet. This may return null if the DataSet was instantiated with a java.sql.ResultSet object.

Returns:

Connection object

schema

public Schema schema()
              throws java.sql.SQLException,
                     DataSetException

Returns the Schema object of a DataSet.

Returns:

Schema object

Throws:

java.sql.SQLException - if there is a SQL error

DataSetException - if there is a data error

size

public int size()

Returns the number of Records in a DataSet.

Returns:

Number of Records

allRecordsRetrieved

public boolean allRecordsRetrieved()

Determines whether all records for a DataSet have been retrieved.

Returns:

True if query is complete

reset

public DataSet reset()
              throws DataSetException,
                     java.sql.SQLException

Clears the current contents of a DataSet. This will cause a requery to the database on the next fetch action. This method cannot be called on QueryDataSets instantiated with an explicit java.sql.ResultSet argument.

Returns:

DataSet object

Throws:

java.sql.SQLException - if there is a SQL error

DataSetException - if there is a data error

clearRecords

public DataSet clearRecords()

Clears all Records from a DataSet.

Returns:

DataSet object

releaseRecords

public DataSet releaseRecords()
                       throws java.sql.SQLException,
                              DataSetException

Closes the DataSet and releases all Records from it but does not nullify them. This is so a DataSet can be reused to generate new records while any records still held by the application remain readable.

Returns:

DataSet object

Throws:

java.sql.SQLException - if there is a SQL error

DataSetException - if there is a problem with the DataSet

getRecord

public Record getRecord(int pos)
                 throws DataSetException

Gets a Record at the specified 0-based index position in a DataSet.

Parameters:

pos - 0-based index in the DataSet

Returns:

Record object

Throws:

DataSetException - if Record is not found at that position

lastFetchSize

public int lastFetchSize()

Returns the number of records fetched in the previous fetch action.

Returns:

Number of records fetched

fetchRecords

public DataSet fetchRecords()
                     throws java.sql.SQLException,
                            DataSetException

Fetches all records.

Returns:

DataSet object

Throws:

java.sql.SQLException - if the records cannot be retrieved

DataSetException - if there is a problem with the DataSet

fetchRecords

public DataSet fetchRecords(int maxrecs)
                     throws java.sql.SQLException,
                            DataSetException

Fetches at most the specified number of records.

Parameters:

maxrecs - Maximum number of records to fetch

Returns:

DataSet object

Throws:

java.sql.SQLException - if the records cannot be retrieved

DataSetException - if there is a problem with the DataSet

fetchRecords

public DataSet fetchRecords(int start,
                            int maxrecs)
                     throws java.sql.SQLException,
                            DataSetException

Fetches at most the specified number of records starting at the specified record.

Parameters:

start - Position of first record to fetch

maxrecs - Maximum number of records to fetch

Returns:

DataSet object

Throws:

java.sql.SQLException - if the records cannot be retrieved

DataSetException - if there is a problem with the DataSet

close

public void close()
           throws java.sql.SQLException,
                  DataSetException

Closes all the resources associated with a DataSet.

Throws:

DataSetException - if there is an error with the DataSet

java.sql.SQLException - if there is a SQL error

addRecord

public Record addRecord()
                 throws DataSetException,
                        java.sql.SQLException

Adds a new Record to a DataSet.

Returns:

Record object

Throws:

DataSetException - if the Record cannot be added

java.sql.SQLException - if there is a SQL error

removeRecord

public Record removeRecord(Record rec)
                    throws DataSetException

Removes the specified Record object from a DataSet.

Parameters:

rec - Record to be removed

Returns:

Record removed

Throws:

DataSetException - if the Record is not present

getSelectString

public abstract java.lang.String getSelectString()

Gets the SelectStatement associated with a DataSet.

Returns:

SelectStatement

containsRecord

public boolean containsRecord(int pos)

Determines whether a Record exists at the specified position.

Parameters:

pos - Index into the DataSet

Returns:

True if Record exists

toString

public java.lang.String toString()

Returns the string representation of all the Records of a DataSet.

Returns:

String value

Overrides:

toString in class java.lang.Object

maxColumnWidths

public int[] maxColumnWidths(boolean with_heading)
                      throws DataSetException,
                             java.sql.SQLException

Calculates the maximum widths of the columns in a DataSet.

Parameters:

with_heading - True if width of column headings should be included in calculation

Returns:

Maximum widths of all columns

Throws:

DataSetException - if there is an error in the DataSet

java.sql.SQLException - if there is a SQL error

initialize

public void initialize()

Internal use only.

destroy

public void destroy()

Internal use only.

readObject

public void readObject(WLObjectInput sis)
                throws java.io.IOException,
                       java.lang.ClassNotFoundException

Internal use only.

Specified by:

readObject in interface WLSerializable

Throws:

java.io.IOException - if there is an error

java.lang.ClassNotFoundException - if there is an error

writeObject

public void writeObject(WLObjectOutput sos)
                 throws java.io.IOException

Internal use only.

Specified by:

writeObject in interface WLSerializable