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| javax.sql.rowset.WebRowSet
| WebRowSet | | public interface WebRowSet extends CachedRowSet(Code) | | The standard interface that all implementations of a WebRowSet
must implement.
1.0 Overview
The 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.xsd
It 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/sqlxml
The schema definition describes the internal data of a RowSet object
in three distinct areas:
- properties
These properties describe the standard synchronization provider properties in
addition to the more general RowSet properties.
- metadata
This describes the metadata associated with the tabular structure governed by a
WebRowSet object. The metadata described is closely aligned with the
metadata accessible in the underlying java.sql.ResultSet interface.
- data
This describes the original data (the state of data since the last population
or last synchronization of the 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.
2.0 WebRowSet States
The following sections demonstrates how a 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.
2.1 State 1 - Outputting a 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 CachedRowSetTM 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>
2.2 State 2 - Deleting a Row
Deleting a row in a 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>
2.3 State 3 - Inserting a Row
A 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>
2.4 State 4 - Modifying a Row
Modifying a row produces specific XML that records both the new value and the
value that was replaced. The value that was replaced becomes the original value,
and the new value becomes the current value. The following
code moves the cursor to a specific row, performs some modifications, and updates
the row when complete.
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>
See Also: javax.sql.rowset.JdbcRowSet
See Also: javax.sql.rowset.CachedRowSet
See Also: javax.sql.rowset.FilteredRowSet
See Also: javax.sql.rowset.JoinRowSet |
| Field Summary | |
| public 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. | | public 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. |
| Method Summary | |
| public void | readXml(java.io.Reader reader)
Reads a WebRowSet object in its XML format from the given
Reader object. | | public void | readXml(java.io.InputStream iStream)
Reads a stream based XML input to populate this WebRowSet
object. | | public void | writeXml(ResultSet rs, java.io.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.
NOTE: The WebRowSet cursor may be moved to write out the
contents to the XML data source. | | public void | writeXml(ResultSet rs, java.io.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.
NOTE: The WebRowSet cursor may be moved to write out the
contents to the XML data source. | | public void | writeXml(java.io.Writer writer)
Writes the data, properties, and metadata for this WebRowSet object
to the given Writer object in XML format. | | public void | writeXml(java.io.OutputStream oStream)
Writes the data, properties, and metadata for this WebRowSet object
to the given OutputStream object in XML format. |
| PUBLIC_XML_SCHEMA | | public static String PUBLIC_XML_SCHEMA(Code) | | The public identifier for the XML Schema definition that defines the XML
tags and their valid values for a WebRowSet implementation.
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| SCHEMA_SYSTEM_ID | | public static String SCHEMA_SYSTEM_ID(Code) | | The URL for the XML Schema definition file that defines the XML tags and
their valid values for a WebRowSet implementation.
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| readXml | | public void readXml(java.io.Reader reader) throws SQLException(Code) | | Reads a WebRowSet object in its XML format from the given
Reader object.
Parameters:
reader - the java.io.Reader stream from which thisWebRowSet object will be populated
throws:
SQLException - if a database access error occurs |
| readXml | | public void readXml(java.io.InputStream iStream) throws SQLException, IOException(Code) | | Reads a stream based XML input to populate this WebRowSet
object.
Parameters:
iStream - the java.io.InputStream from which thisWebRowSet object will be populated
throws:
SQLException - if a data source access error occurs
throws:
IOException - if an IO exception occurs |
| writeXml | | public void writeXml(ResultSet rs, java.io.Writer writer) throws SQLException(Code) | | 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.
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.
Parameters:
rs - the ResultSet object with which to populate thisWebRowSet object
Parameters:
writer - the java.io.Writer object to write to.
throws:
SQLException - if an error occurs writing out the rowsetcontents in XML format |
| writeXml | | public void writeXml(ResultSet rs, java.io.OutputStream oStream) throws SQLException, IOException(Code) | | 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.
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.
Parameters:
rs - the ResultSet object with which to populate thisWebRowSet object
Parameters:
oStream - the java.io.OutputStream to write to
throws:
SQLException - if a data source access error occurs
throws:
IOException - if a IO exception occurs |
| writeXml | | public void writeXml(java.io.Writer writer) throws SQLException(Code) | | Writes the data, properties, and metadata for this WebRowSet object
to the given Writer object in XML format.
Parameters:
writer - the java.io.Writer stream to write to
throws:
SQLException - if an error occurs writing out the rowsetcontents to XML |
| writeXml | | public void writeXml(java.io.OutputStream oStream) throws SQLException, IOException(Code) | | Writes the data, properties, and metadata for this WebRowSet object
to the given OutputStream object in XML format.
Parameters:
oStream - the java.io.OutputStream stream to write to
throws:
SQLException - if a data source access error occurs
throws:
IOException - if a IO exception occurs |
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