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Java™ Platform Standard Ed. 6 |
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public interface WebRowSet
The standard interface that all implementations of a WebRowSet
must implement.
WebRowSetImpl
provides the standard
reference implementation, which may be extended if required.
The standard WebRowSet XML Schema definition is available at the following URI:
http://java.sun.com/xml/ns/jdbc/webrowset.xsdIt describes the standard XML document format required when describing a
RowSet
object in XML and must be used be all standard implementations
of the WebRowSet
interface to ensure interoperability. In addition,
the WebRowSet
schema uses specific SQL/XML Schema annotations,
thus ensuring greater cross
platform inter-operability. This is an effort currently under way at the ISO
organization. The SQL/XML definition is available at the following URI:
http://standards.iso.org/iso/9075/2002/12/sqlxmlThe schema definition describes the internal data of a
RowSet
object
in three distinct areas:
RowSet
properties.
WebRowSet
object. The metadata described is closely aligned with the
metadata accessible in the underlying java.sql.ResultSet
interface.
WebRowSet
object) and the current
data. By keeping track of the delta between the original data and the current data,
a WebRowSet
maintains
the ability to synchronize changes in its data back to the originating data source.
WebRowSet
implementation
should use the XML Schema to describe update, insert, and delete operations
and to describe the state of a WebRowSet
object in XML.
WebRowSet
Object to XML
In this example, a WebRowSet
object is created and populated with a simple 2 column,
5 row table from a data source. Having the 5 rows in a WebRowSet
object
makes it possible to describe them in XML. The
metadata describing the various standard JavaBeans properties as defined
in the RowSet interface plus the standard properties defined in
the CachedRowSet
TM interface
provide key details that describe WebRowSet
properties. Outputting the WebRowSet object to XML using the standard
writeXml
methods describes the internal properties as follows:
<properties> <command>select co1, col2 from test_table</command> <concurrency>1</concurrency> <datasource/> <escape-processing>true</escape-processing> <fetch-direction>0</fetch-direction> <fetch-size>0</fetch-size> <isolation-level>1</isolation-level> <key-columns/> <map/> <max-field-size>0</max-field-size> <max-rows>0</max-rows> <query-timeout>0</query-timeout> <read-only>false</read-only> <rowset-type>TRANSACTION_READ_UNCOMMITED</rowset-type> <show-deleted>false</show-deleted> <table-name/> <url>jdbc:thin:oracle</url> <sync-provider> <sync-provider-name>.com.rowset.provider.RIOptimisticProvider</sync-provider-name> <sync-provider-vendor>Sun Microsystems</sync-provider-vendor> <sync-provider-version>1.0</sync-provider-name> <sync-provider-grade>LOW</sync-provider-grade> <data-source-lock>NONE</data-source-lock> </sync-provider> </properties>The meta-data describing the make up of the WebRowSet is described in XML as detailed below. Note both columns are described between the
column-definition
tags.
<metadata> <column-count>2</column-count> <column-definition> <column-index>1</column-index> <auto-increment>false</auto-increment> <case-sensitive>true</case-sensitive> <currency>false</currency> <nullable>1</nullable> <signed>false</signed> <searchable>true</searchable> <column-display-size>10</column-display-size> <column-label>COL1</column-label> <column-name>COL1</column-name> <schema-name/> <column-precision>10</column-precision> <column-scale>0</column-scale> <table-name/> <catalog-name/> <column-type>1</column-type> <column-type-name>CHAR</column-type-name> </column-definition> <column-definition> <column-index>2</column-index> <auto-increment>false</auto-increment> <case-sensitive>false</case-sensitive> <currency>false</currency> <nullable>1</nullable> <signed>true</signed> <searchable>true</searchable> <column-display-size>39</column-display-size> <column-label>COL2</column-label> <column-name>COL2</column-name> <schema-name/> <column-precision>38</column-precision> <column-scale>0</column-scale> <table-name/> <catalog-name/> <column-type>3</column-type> <column-type-name>NUMBER</column-type-name> </column-definition> </metadata>Having detailed how the properties and metadata are described, the following details how the contents of a
WebRowSet
object is described in XML. Note, that
this describes a WebRowSet
object that has not undergone any
modifications since its instantiation.
A currentRow
tag is mapped to each row of the table structure that the
WebRowSet
object provides. A columnValue
tag may contain
either the stringData
or binaryData
tag, according to
the SQL type that
the XML value is mapping back to. The binaryData
tag contains data in the
Base64 encoding and is typically used for BLOB
and CLOB
type data.
<data> <currentRow> <columnValue> firstrow </columnValue> <columnValue> 1 </columnValue> </currentRow> <currentRow> <columnValue> secondrow </columnValue> <columnValue> 2 </columnValue> </currentRow> <currentRow> <columnValue> thirdrow </columnValue> <columnValue> 3 </columnValue> </currentRow> <currentRow> <columnValue> fourthrow </columnValue> <columnValue> 4 </columnValue> </currentRow> </data>
WebRowSet
object involves simply moving to the row
to be deleted and then calling the method deleteRow
, as in any other
RowSet
object. The following
two lines of code, in which wrs is a WebRowSet
object, delete
the third row.
wrs.absolute(3); wrs.deleteRow();The XML description shows the third row is marked as a
deleteRow
,
which eliminates the third row in the WebRowSet
object.
<data> <currentRow> <columnValue> firstrow </columnValue> <columnValue> 1 </columnValue> </currentRow> <currentRow> <columnValue> secondrow </columnValue> <columnValue> 2 </columnValue> </currentRow> <deleteRow> <columnValue> thirdrow </columnValue> <columnValue> 3 </columnValue> </deleteRow> <currentRow> <columnValue> fourthrow </columnValue> <columnValue> 4 </columnValue> </currentRow> </data>
WebRowSet
object can insert a new row by moving to the insert row,
calling the appropriate updater methods for each column in the row, and then
calling the method insertRow
.
wrs.moveToInsertRow(); wrs.updateString(1, "fifththrow"); wrs.updateString(2, "5"); wrs.insertRow();The following code fragment changes the second column value in the row just inserted. Note that this code applies when new rows are inserted right after the current row, which is why the method
next
moves the cursor to the correct row.
Calling the method acceptChanges
writes the change to the data source.
wrs.moveToCurrentRow(); wrs.next(); wrs.updateString(2, "V"); wrs.acceptChanges(); :Describing this in XML demonstrates where the Java code inserts a new row and then performs an update on the newly inserted row on an individual field.
<data> <currentRow> <columnValue> firstrow </columnValue> <columnValue> 1 </columnValue> </currentRow> <currentRow> <columnValue> secondrow </columnValue> <columnValue> 2 </columnValue> </currentRow> <currentRow> <columnValue> newthirdrow </columnValue> <columnValue> III </columnValue> </currentRow> <insertRow> <columnValue> fifthrow </columnValue> <columnValue> 5 </columnValue> <updateValue> V </updateValue> </insertRow> <currentRow> <columnValue> fourthrow </columnValue> <columnValue> 4 </columnValue> </currentRow> </date>
wrs.absolute(5); wrs.updateString(1, "new4thRow"); wrs.updateString(2, "IV"); wrs.updateRow();In XML, this is described by the
modifyRow
tag. Both the original and new
values are contained within the tag for original row tracking purposes.
<data> <currentRow> <columnValue> firstrow </columnValue> <columnValue> 1 </columnValue> </currentRow> <currentRow> <columnValue> secondrow </columnValue> <columnValue> 2 </columnValue> </currentRow> <currentRow> <columnValue> newthirdrow </columnValue> <columnValue> III </columnValue> </currentRow> <currentRow> <columnValue> fifthrow </columnValue> <columnValue> 5 </columnValue> </currentRow> <modifyRow> <columnValue> fourthrow </columnValue> <updateValue> new4thRow </updateValue> <columnValue> 4 </columnValue> <updateValue> IV </updateValue> </modifyRow> </data>
JdbcRowSet
,
CachedRowSet
,
FilteredRowSet
,
JoinRowSet
Field Summary | |
---|---|
static String |
PUBLIC_XML_SCHEMA
The public identifier for the XML Schema definition that defines the XML tags and their valid values for a WebRowSet implementation. |
static String |
SCHEMA_SYSTEM_ID
The URL for the XML Schema definition file that defines the XML tags and their valid values for a WebRowSet implementation. |
Fields inherited from interface javax.sql.rowset.CachedRowSet |
---|
COMMIT_ON_ACCEPT_CHANGES |
Fields inherited from 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 |
Method Summary | |
---|---|
void |
readXml(InputStream iStream)
Reads a stream based XML input to populate this WebRowSet
object. |
void |
readXml(Reader reader)
Reads a WebRowSet object in its XML format from the given
Reader object. |
void |
writeXml(OutputStream oStream)
Writes the data, properties, and metadata for this WebRowSet object
to the given OutputStream object in XML format. |
void |
writeXml(ResultSet rs,
OutputStream oStream)
Populates this WebRowSet object with
the contents of the given ResultSet object and writes its
data, properties, and metadata
to the given OutputStream object in XML format. |
void |
writeXml(ResultSet rs,
Writer writer)
Populates this WebRowSet object with
the contents of the given ResultSet object and writes its
data, properties, and metadata
to the given Writer object in XML format. |
void |
writeXml(Writer writer)
Writes the data, properties, and metadata for this WebRowSet object
to the given Writer object in XML format. |
Methods inherited from 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 inherited from interface java.sql.Wrapper |
---|
isWrapperFor, unwrap |
Methods inherited from interface javax.sql.rowset.Joinable |
---|
getMatchColumnIndexes, getMatchColumnNames, setMatchColumn, setMatchColumn, setMatchColumn, setMatchColumn, unsetMatchColumn, unsetMatchColumn, unsetMatchColumn, unsetMatchColumn |
Field Detail |
---|
static final String PUBLIC_XML_SCHEMA
WebRowSet
implementation.
static final String SCHEMA_SYSTEM_ID
WebRowSet
implementation.
Method Detail |
---|
void readXml(Reader reader) throws SQLException
WebRowSet
object in its XML format from the given
Reader
object.
reader
- the java.io.Reader
stream from which this
WebRowSet
object will be populated
SQLException
- if a database access error occursvoid readXml(InputStream iStream) throws SQLException, IOException
WebRowSet
object.
iStream
- the java.io.InputStream
from which this
WebRowSet
object will be populated
SQLException
- if a data source access error occurs
IOException
- if an IO exception occursvoid writeXml(ResultSet rs, Writer writer) throws SQLException
WebRowSet
object with
the contents of the given ResultSet
object and writes its
data, properties, and metadata
to the given Writer
object in XML format.
NOTE: The WebRowSet
cursor may be moved to write out the
contents to the XML data source. If implemented in this way, the cursor must
be returned to its position just prior to the writeXml()
call.
rs
- the ResultSet
object with which to populate this
WebRowSet
objectwriter
- the java.io.Writer
object to write to.
SQLException
- if an error occurs writing out the rowset
contents in XML formatvoid writeXml(ResultSet rs, OutputStream oStream) throws SQLException, IOException
WebRowSet
object with
the contents of the given ResultSet
object and writes its
data, properties, and metadata
to the given OutputStream
object in XML format.
NOTE: The WebRowSet
cursor may be moved to write out the
contents to the XML data source. If implemented in this way, the cursor must
be returned to its position just prior to the writeXml()
call.
rs
- the ResultSet
object with which to populate this
WebRowSet
objectoStream
- the java.io.OutputStream
to write to
SQLException
- if a data source access error occurs
IOException
- if a IO exception occursvoid writeXml(Writer writer) throws SQLException
WebRowSet
object
to the given Writer
object in XML format.
writer
- the java.io.Writer
stream to write to
SQLException
- if an error occurs writing out the rowset
contents to XMLvoid writeXml(OutputStream oStream) throws SQLException, IOException
WebRowSet
object
to the given OutputStream
object in XML format.
oStream
- the java.io.OutputStream
stream to write to
SQLException
- if a data source access error occurs
IOException
- if a IO exception occurs
|
Java™ Platform Standard Ed. 6 |
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