Interface FilteredRowSet
- All Superinterfaces:
AutoCloseable
,CachedRowSet
,Joinable
,ResultSet
,RowSet
,WebRowSet
,Wrapper
FilteredRowSet
must implement. The FilteredRowSetImpl
class
provides the reference implementation which may be extended if required.
Alternatively, a vendor is free to implement its own version
by implementing this interface.
1.0 Background
There are occasions when aRowSet
object has a need to provide a degree
of filtering to its contents. One possible solution is to provide
a query language for all standard RowSet
implementations; however,
this is an impractical approach for lightweight components such as disconnected
RowSet
objects. The FilteredRowSet
interface seeks to address this need
without supplying a heavyweight query language along with the processing that
such a query language would require.
A JDBC FilteredRowSet
standard implementation implements the
RowSet
interfaces and extends the
CachedRowSet
class. The
CachedRowSet
class provides a set of protected cursor manipulation
methods, which a FilteredRowSet
implementation can override
to supply filtering support.
2.0 Predicate Sharing
If aFilteredRowSet
implementation is shared using the
inherited createShared
method in parent interfaces, the
Predicate
should be shared without modification by all
FilteredRowSet
instance clones.
3.0 Usage
By implementing a Predicate
(see example in Predicate
class JavaDoc), a FilteredRowSet
could then be used as described
below.
FilteredRowSet frs = new FilteredRowSetImpl();
frs.populate(rs);
Range name = new Range("Alpha", "Bravo", "columnName");
frs.setFilter(name);
frs.next() // only names from "Alpha" to "Bravo" will be returned
In the example above, we initialize a Range
object which
implements the Predicate
interface. This object expresses
the following constraints: All rows outputted or modified from this
FilteredRowSet
object must fall between the values 'Alpha' and
'Bravo' both values inclusive, in the column 'columnName'. If a filter is
applied to a FilteredRowSet
object that contains no data that
falls within the range of the filter, no rows are returned.
This framework allows multiple classes implementing predicates to be used in combination to achieved the required filtering result with out the need for query language processing.
4.0 Updating a FilteredRowSet
Object
The predicate set on a FilteredRowSet
object
applies a criterion on all rows in a
RowSet
object to manage a subset of rows in a RowSet
object. This criterion governs the subset of rows that are visible and also
defines which rows can be modified, deleted or inserted.
Therefore, the predicate set on a FilteredRowSet
object must be
considered as bi-directional and the set criterion as the gating mechanism
for all views and updates to the FilteredRowSet
object. Any attempt
to update the FilteredRowSet
that violates the criterion will
result in a SQLException
object being thrown.
The FilteredRowSet
range criterion can be modified by applying
a new Predicate
object to the FilteredRowSet
instance at any time. This is possible if no additional references to the
FilteredRowSet
object are detected. A new filter has an
immediate effect on criterion enforcement within the
FilteredRowSet
object, and all subsequent views and updates will be
subject to similar enforcement.
5.0 Behavior of Rows Outside the Filter
Rows that fall outside of the filter set on aFilteredRowSet
object cannot be modified until the filter is removed or a
new filter is applied.
Furthermore, only rows that fall within the bounds of a filter will be synchronized with the data source.
- Since:
- 1.5
-
Field Summary
Fields declared in interface javax.sql.rowset.CachedRowSet
COMMIT_ON_ACCEPT_CHANGES
Fields declared in interface java.sql.ResultSet
CLOSE_CURSORS_AT_COMMIT, CONCUR_READ_ONLY, CONCUR_UPDATABLE, FETCH_FORWARD, FETCH_REVERSE, FETCH_UNKNOWN, HOLD_CURSORS_OVER_COMMIT, TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE, TYPE_SCROLL_SENSITIVE
Fields declared in interface javax.sql.rowset.WebRowSet
PUBLIC_XML_SCHEMA, SCHEMA_SYSTEM_ID
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Method Summary
Methods declared in interface javax.sql.rowset.CachedRowSet
acceptChanges, acceptChanges, columnUpdated, columnUpdated, commit, createCopy, createCopyNoConstraints, createCopySchema, createShared, execute, getKeyColumns, getOriginal, getOriginalRow, getPageSize, getRowSetWarnings, getShowDeleted, getSyncProvider, getTableName, nextPage, populate, populate, previousPage, release, restoreOriginal, rollback, rollback, rowSetPopulated, setKeyColumns, setMetaData, setOriginalRow, setPageSize, setShowDeleted, setSyncProvider, setTableName, size, toCollection, toCollection, toCollection, undoDelete, undoInsert, undoUpdate
Methods declared in interface javax.sql.rowset.Joinable
getMatchColumnIndexes, getMatchColumnNames, setMatchColumn, setMatchColumn, setMatchColumn, setMatchColumn, unsetMatchColumn, unsetMatchColumn, unsetMatchColumn, unsetMatchColumn
Methods declared in interface java.sql.ResultSet
absolute, afterLast, beforeFirst, cancelRowUpdates, clearWarnings, close, deleteRow, findColumn, first, getArray, getArray, getAsciiStream, getAsciiStream, getBigDecimal, getBigDecimal, getBigDecimal, getBigDecimal, getBinaryStream, getBinaryStream, getBlob, getBlob, getBoolean, getBoolean, getByte, getByte, getBytes, getBytes, getCharacterStream, getCharacterStream, getClob, getClob, getConcurrency, getCursorName, getDate, getDate, getDate, getDate, getDouble, getDouble, getFetchDirection, getFetchSize, getFloat, getFloat, getHoldability, getInt, getInt, getLong, getLong, getMetaData, getNCharacterStream, getNCharacterStream, getNClob, getNClob, getNString, getNString, getObject, getObject, getObject, getObject, getObject, getObject, getRef, getRef, getRow, getRowId, getRowId, getShort, getShort, getSQLXML, getSQLXML, getStatement, getString, getString, getTime, getTime, getTime, getTime, getTimestamp, getTimestamp, getTimestamp, getTimestamp, getType, getUnicodeStream, getUnicodeStream, getURL, getURL, getWarnings, insertRow, isAfterLast, isBeforeFirst, isClosed, isFirst, isLast, last, moveToCurrentRow, moveToInsertRow, next, previous, refreshRow, relative, rowDeleted, rowInserted, rowUpdated, setFetchDirection, setFetchSize, updateArray, updateArray, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateBigDecimal, updateBigDecimal, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBoolean, updateBoolean, updateByte, updateByte, updateBytes, updateBytes, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateClob, updateClob, updateClob, updateClob, updateClob, updateClob, updateDate, updateDate, updateDouble, updateDouble, updateFloat, updateFloat, updateInt, updateInt, updateLong, updateLong, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNString, updateNString, updateNull, updateNull, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateRef, updateRef, updateRow, updateRowId, updateRowId, updateShort, updateShort, updateSQLXML, updateSQLXML, updateString, updateString, updateTime, updateTime, updateTimestamp, updateTimestamp, wasNull
Methods declared in interface javax.sql.RowSet
addRowSetListener, clearParameters, execute, getCommand, getDataSourceName, getEscapeProcessing, getMaxFieldSize, getMaxRows, getPassword, getQueryTimeout, getTransactionIsolation, getTypeMap, getUrl, getUsername, isReadOnly, removeRowSetListener, setArray, setAsciiStream, setAsciiStream, setAsciiStream, setAsciiStream, setBigDecimal, setBigDecimal, setBinaryStream, setBinaryStream, setBinaryStream, setBinaryStream, setBlob, setBlob, setBlob, setBlob, setBlob, setBlob, setBoolean, setBoolean, setByte, setByte, setBytes, setBytes, setCharacterStream, setCharacterStream, setCharacterStream, setCharacterStream, setClob, setClob, setClob, setClob, setClob, setClob, setCommand, setConcurrency, setDataSourceName, setDate, setDate, setDate, setDate, setDouble, setDouble, setEscapeProcessing, setFloat, setFloat, setInt, setInt, setLong, setLong, setMaxFieldSize, setMaxRows, setNCharacterStream, setNCharacterStream, setNCharacterStream, setNCharacterStream, setNClob, setNClob, setNClob, setNClob, setNClob, setNClob, setNString, setNString, setNull, setNull, setNull, setNull, setObject, setObject, setObject, setObject, setObject, setObject, setPassword, setQueryTimeout, setReadOnly, setRef, setRowId, setRowId, setShort, setShort, setSQLXML, setSQLXML, setString, setString, setTime, setTime, setTime, setTime, setTimestamp, setTimestamp, setTimestamp, setTimestamp, setTransactionIsolation, setType, setTypeMap, setUrl, setURL, setUsername
Methods declared in interface javax.sql.rowset.WebRowSet
readXml, readXml, writeXml, writeXml, writeXml, writeXml
Methods declared in interface java.sql.Wrapper
isWrapperFor, unwrap
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Method Details
-
setFilter
Applies the givenPredicate
object to thisFilteredRowSet
object. The filter applies controls both to inbound and outbound views, constraining which rows are visible and which rows can be manipulated.A new
Predicate
object may be set at any time. This has the effect of changing constraints on theRowSet
object's data. In addition, modifying the filter at runtime presents issues whereby multiple components may be operating on oneFilteredRowSet
object. Application developers must take responsibility for managing multiple handles toFilteredRowSet
objects when their underlingPredicate
objects change.- Parameters:
p
- aPredicate
object defining the filter for thisFilteredRowSet
object. Setting a null value will clear the predicate, allowing all rows to become visible.- Throws:
SQLException
- if an error occurs when setting thePredicate
object
-
getFilter
Predicate getFilter()Retrieves the active filter for thisFilteredRowSet
object.- Returns:
- p the
Predicate
for thisFilteredRowSet
object;null
if no filter has been set.
-