SQLXML


1   /*
2    * %W% %E%
3    *
4    * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.sql;
9   
10  import java.io.InputStream  ;
11  import java.io.OutputStream  ;
12  import java.io.Reader  ;
13  import java.io.Writer  ;
14  
15  import javax.xml.transform.Result  ;
16  import javax.xml.transform.Source  ;
17  
18  /**
19   * The mapping in the JavaTM programming language for the SQL XML type. 
20   * XML is a built-in type that stores an XML value 
21   * as a column value in a row of a database table. 
22   * By default drivers implement an SQLXML object as 
23   * a logical pointer to the XML data 
24   * rather than the data itself. 
25   * An SQLXML object is valid for the duration of the transaction in which it was created. 
26   * <p>
27   * The SQLXML interface provides methods for accessing the XML value
28   * as a String, a Reader or Writer, or as a Stream.  The XML value
29   * may also be accessed through a Source or set as a Result, which
30   * are used with XML Parser APIs such as DOM, SAX, and StAX, as
31   * well as with XSLT transforms and XPath evaluations. 
32   * <p>
33   * Methods in the interfaces ResultSet, CallableStatement, and PreparedStatement, 
34   * such as getSQLXML allow a programmer to access an XML value. 
35   * In addition, this interface has methods for updating an XML value. 
36   * <p>
37   * The XML value of the SQLXML instance may be obtained as a BinaryStream using
38   * <pre>
39   *   SQLXML sqlxml = resultSet.getSQLXML(column);
40   *   InputStream binaryStream = sqlxml.getBinaryStream();
41   * </pre>
42   * For example, to parse an XML value with a DOM parser:
43   * <pre>
44   *   DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder();
45   *   Document result = parser.parse(binaryStream);
46   * </pre>
47   * or to parse an XML value with a SAX parser to your handler:
48   * <pre>
49   *   SAXParser parser = SAXParserFactory.newInstance().newSAXParser();
50   *   parser.parse(binaryStream, myHandler);
51   * </pre>
52   * or to parse an XML value with a StAX parser:
53   * <pre>
54   *   XMLInputFactory factory = XMLInputFactory.newInstance();
55   *   XMLStreamReader streamReader = factory.createXMLStreamReader(binaryStream);
56   * </pre>
57   * <p>
58   * Because databases may use an optimized representation for the XML, 
59   * accessing the value through getSource() and
60   * setResult() can lead to improved processing performance
61   * without serializing to a stream representation and parsing the XML.
62   * <p>
63   * For example, to obtain a DOM Document Node:
64   * <pre>
65   *   DOMSource domSource = sqlxml.getSource(DOMSource.class);
66   *   Document document = (Document) domSource.getNode();
67   * </pre>
68   * or to set the value to a DOM Document Node to myNode:
69   * <pre>
70   *   DOMResult domResult = sqlxml.setResult(DOMResult.class);
71   *   domResult.setNode(myNode);
72   * </pre>
73   * or, to send SAX events to your handler:
74   * <pre>
75   *   SAXSource saxSource = sqlxml.getSource(SAXSource.class);
76   *   XMLReader xmlReader = saxSource.getXMLReader();
77   *   xmlReader.setContentHandler(myHandler);
78   *   xmlReader.parse(saxSource.getInputSource());
79   * </pre>
80   * or, to set the result value from SAX events:
81   * <pre>
82   *   SAXResult saxResult = sqlxml.setResult(SAXResult.class);
83   *   ContentHandler contentHandler = saxResult.getXMLReader().getContentHandler();
84   *   contentHandler.startDocument();
85   *   // set the XML elements and attributes into the result
86   *   contentHandler.endDocument();
87   * </pre>
88   * or, to obtain StAX events:
89   * <pre>
90   *   StAXSource staxSource = sqlxml.getSource(StAXSource.class);
91   *   XMLStreamReader streamReader = staxSource.getXMLStreamReader();
92   * </pre>
93   * or, to set the result value from StAX events:
94   * <pre>
95   *   StAXResult staxResult = sqlxml.setResult(StAXResult.class);
96   *   XMLStreamWriter streamWriter = staxResult.getXMLStreamWriter();
97   * </pre>
98   * or, to perform XSLT transformations on the XML value using the XSLT in xsltFile
99   * output to file resultFile:
100  * <pre>
101  *   File xsltFile = new File("a.xslt");
102  *   File myFile = new File("result.xml");
103  *   Transformer xslt = TransformerFactory.newInstance().newTransformer(new StreamSource(xsltFile));
104  *   Source source = sqlxml.getSource(null);
105  *   Result result = new StreamResult(myFile);
106  *   xslt.transform(source, result);
107  * </pre>
108  * or, to evaluate an XPath expression on the XML value:
109  * <pre>
110  *   XPath xpath = XPathFactory.newInstance().newXPath();
111  *   DOMSource domSource = sqlxml.getSource(DOMSource.class);
112  *   Document document = (Document) domSource.getNode();
113  *   String expression = "/foo/@bar";
114  *   String barValue = xpath.evaluate(expression, document);
115  * </pre>
116  * To set the XML value to be the result of an XSLT transform: 
117  * <pre>
118  *   File sourceFile = new File("source.xml");
119  *   Transformer xslt = TransformerFactory.newInstance().newTransformer(new StreamSource(xsltFile));
120  *   Source streamSource = new StreamSource(sourceFile);
121  *   Result result = sqlxml.setResult(null);
122  *   xslt.transform(streamSource, result);
123  * </pre>
124  * Any Source can be transformed to a Result using the identity transform
125  * specified by calling newTransformer():
126  * <pre>
127  *   Transformer identity = TransformerFactory.newInstance().newTransformer();
128  *   Source source = sqlxml.getSource(null);
129  *   File myFile = new File("result.xml");
130  *   Result result = new StreamResult(myFile);
131  *   identity.transform(source, result);
132  * </pre>
133  * To write the contents of a Source to standard output:
134  * <pre>
135  *   Transformer identity = TransformerFactory.newInstance().newTransformer();
136  *   Source source = sqlxml.getSource(null);
137  *   Result result = new StreamResult(System.out);
138  *   identity.transform(source, result);
139  * </pre>
140  * To create a DOMSource from a DOMResult:
141  * <pre>
142  *    DOMSource domSource = new DOMSource(domResult.getNode()); 
143  * </pre>
144  * <p>
145  * Incomplete or invalid XML values may cause an SQLException when
146  * set or the exception may occur when execute() occurs.  All streams
147  * must be closed before execute() occurs or an SQLException will be thrown.
148  * <p>
149  * Reading and writing XML values to or from an SQLXML object can happen at most once.
150  * The conceptual states of readable and not readable determine if one
151  * of the reading APIs will return a value or throw an exception.
152  * The conceptual states of writable and not writable determine if one
153  * of the writing APIs will set a value or throw an exception.
154  * <p>
155  * The state moves from readable to not readable once free() or any of the
156  * reading APIs are called: getBinaryStream(), getCharacterStream(), getSource(), and getString().
157  * Implementations may also change the state to not writable when this occurs.
158  * <p>
159  * The state moves from writable to not writeable once free() or any of the
160  * writing APIs are called: setBinaryStream(), setCharacterStream(), setResult(), and setString().
161  * Implementations may also change the state to not readable when this occurs.
162  * <p>
163   * <p>
164  * All methods on the <code>SQLXML</code> interface must be fully implemented if the 
165  * JDBC driver supports the data type.
166  *
167  * @see javax.xml.parsers
168  * @see javax.xml.stream
169  * @see javax.xml.transform
170  * @see javax.xml.xpath
171  * @since 1.6
172  */
173 public interface SQLXML
174 {
175   /**
176    * This method closes this object and releases the resources that it held.
177    * The SQL XML object becomes invalid and neither readable or writeable 
178    * when this method is called.
179    *
180    * After <code>free</code> has been called, any attempt to invoke a
181    * method other than <code>free</code> will result in a <code>SQLException</code> 
182    * being thrown.  If <code>free</code> is called multiple times, the subsequent
183    * calls to <code>free</code> are treated as a no-op.
184    * @throws SQLException if there is an error freeing the XML value.
185    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
186    * this method
187    * @since 1.6
188    */
189   void free() throws SQLException  ;
190 
191   /**
192    * Retrieves the XML value designated by this SQLXML instance as a stream.  
193    * The bytes of the input stream are interpreted according to appendix F of the XML 1.0 specification. 
194    * The behavior of this method is the same as ResultSet.getBinaryStream()
195    * when the designated column of the ResultSet has a type java.sql.Types of SQLXML.
196    * <p>
197    * The SQL XML object becomes not readable when this method is called and
198    * may also become not writable depending on implementation.
199    * 
200    * @return a stream containing the XML data.
201    * @throws SQLException if there is an error processing the XML value.
202    *   An exception is thrown if the state is not readable.
203    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
204    * this method
205    * @since 1.6
206    */
207   InputStream   getBinaryStream() throws SQLException  ;
208   
209   /**
210    * Retrieves a stream that can be used to write the XML value that this SQLXML instance represents. 
211    * The stream begins at position 0. 
212    * The bytes of the stream are interpreted according to appendix F of the XML 1.0 specification
213    * The behavior of this method is the same as ResultSet.updateBinaryStream()
214    * when the designated column of the ResultSet has a type java.sql.Types of SQLXML.
215    * <p>
216    * The SQL XML object becomes not writeable when this method is called and
217    * may also become not readable depending on implementation.
218    * 
219    * @return a stream to which data can be written.
220    * @throws SQLException if there is an error processing the XML value.
221    *   An exception is thrown if the state is not writable.
222    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
223    * this method
224    * @since 1.6
225    */
226   OutputStream   setBinaryStream() throws SQLException  ;
227   
228   /**
229    * Retrieves the XML value designated by this SQLXML instance as a java.io.Reader object.
230    * The format of this stream is defined by org.xml.sax.InputSource,
231    * where the characters in the stream represent the unicode code points for  
232    * XML according to section 2 and appendix B of the XML 1.0 specification.
233    * Although an encoding declaration other than unicode may be present, 
234    * the encoding of the stream is unicode.
235    * The behavior of this method is the same as ResultSet.getCharacterStream()
236    * when the designated column of the ResultSet has a type java.sql.Types of SQLXML.
237    * <p>
238    * The SQL XML object becomes not readable when this method is called and
239    * may also become not writable depending on implementation.
240    * 
241    * @return a stream containing the XML data.
242    * @throws SQLException if there is an error processing the XML value.
243    *   The getCause() method of the exception may provide a more detailed exception, for example,
244    *   if the stream does not contain valid characters. 
245    *   An exception is thrown if the state is not readable.
246    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
247    * this method
248    * @since 1.6
249    */
250   Reader   getCharacterStream() throws SQLException  ;
251   
252   /**
253    * Retrieves a stream to be used to write the XML value that this SQLXML instance represents.
254    * The format of this stream is defined by org.xml.sax.InputSource,
255    * where the characters in the stream represent the unicode code points for  
256    * XML according to section 2 and appendix B of the XML 1.0 specification.
257    * Although an encoding declaration other than unicode may be present, 
258    * the encoding of the stream is unicode.
259    * The behavior of this method is the same as ResultSet.updateCharacterStream()
260    * when the designated column of the ResultSet has a type java.sql.Types of SQLXML.
261    * <p>
262    * The SQL XML object becomes not writeable when this method is called and
263    * may also become not readable depending on implementation.
264    * 
265    * @return a stream to which data can be written.
266    * @throws SQLException if there is an error processing the XML value.
267    *   The getCause() method of the exception may provide a more detailed exception, for example,
268    *   if the stream does not contain valid characters. 
269    *   An exception is thrown if the state is not writable.
270    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
271    * this method
272    * @since 1.6
273    */
274   Writer   setCharacterStream() throws SQLException  ;
275 
276   /**
277    * Returns a string representation of the XML value designated by this SQLXML instance.
278    * The format of this String is defined by org.xml.sax.InputSource,
279    * where the characters in the stream represent the unicode code points for  
280    * XML according to section 2 and appendix B of the XML 1.0 specification.
281    * Although an encoding declaration other than unicode may be present, 
282    * the encoding of the String is unicode.
283    * The behavior of this method is the same as ResultSet.getString()
284    * when the designated column of the ResultSet has a type java.sql.Types of SQLXML.
285    * <p>
286    * The SQL XML object becomes not readable when this method is called and
287    * may also become not writable depending on implementation.
288    * 
289    * @return a string representation of the XML value designated by this SQLXML instance.
290    * @throws SQLException if there is an error processing the XML value.
291    *   The getCause() method of the exception may provide a more detailed exception, for example,
292    *   if the stream does not contain valid characters. 
293    *   An exception is thrown if the state is not readable.
294    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
295    * this method
296    * @since 1.6
297    */
298   String   getString() throws SQLException  ; 
299   
300   /**
301    * Sets the XML value designated by this SQLXML instance to the given String representation. 
302    * The format of this String is defined by org.xml.sax.InputSource,
303    * where the characters in the stream represent the unicode code points for  
304    * XML according to section 2 and appendix B of the XML 1.0 specification.
305    * Although an encoding declaration other than unicode may be present, 
306    * the encoding of the String is unicode.
307    * The behavior of this method is the same as ResultSet.updateString()
308    * when the designated column of the ResultSet has a type java.sql.Types of SQLXML.
309    * <p>
310    * The SQL XML object becomes not writeable when this method is called and
311    * may also become not readable depending on implementation.
312    * 
313    * @param value the XML value
314    * @throws SQLException if there is an error processing the XML value.
315    *   The getCause() method of the exception may provide a more detailed exception, for example,
316    *   if the stream does not contain valid characters. 
317    *   An exception is thrown if the state is not writable.
318    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
319    * this method
320    * @since 1.6
321    */
322   void setString(String   value) throws SQLException  ; 
323   
324   /**
325    * Returns a Source for reading the XML value designated by this SQLXML instance.
326    * Sources are used as inputs to XML parsers and XSLT transformers.
327    * <p>
328    * Sources for XML parsers will have namespace processing on by default.
329    * The systemID of the Source is implementation dependent.
330    * <p>
331    * The SQL XML object becomes not readable when this method is called and
332    * may also become not writable depending on implementation.
333    * <p>
334    * Note that SAX is a callback architecture, so a returned
335    * SAXSource should then be set with a content handler that will
336    * receive the SAX events from parsing.  The content handler
337    * will receive callbacks based on the contents of the XML.
338    * <pre>
339    *   SAXSource saxSource = sqlxml.getSource(SAXSource.class);
340    *   XMLReader xmlReader = saxSource.getXMLReader();
341    *   xmlReader.setContentHandler(myHandler);
342    *   xmlReader.parse(saxSource.getInputSource());
343    * </pre>
344    * 
345    * @param sourceClass The class of the source, or null.  
346    * If the class is null, a vendor specifc Source implementation will be returned.
347    * The following classes are supported at a minimum:
348    * <pre>
349    *   javax.xml.transform.dom.DOMSource - returns a DOMSource
350    *   javax.xml.transform.sax.SAXSource - returns a SAXSource
351    *   javax.xml.transform.stax.StAXSource - returns a StAXSource
352    *   javax.xml.transform.stream.StreamSource - returns a StreamSource
353    * </pre>
354    * @return a Source for reading the XML value.
355    * @throws SQLException if there is an error processing the XML value
356    *   or if this feature is not supported.
357    *   The getCause() method of the exception may provide a more detailed exception, for example,
358    *   if an XML parser exception occurs. 
359    *   An exception is thrown if the state is not readable.
360    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
361    * this method
362    * @since 1.6
363    */
364   <T extends Source  > T getSource(Class  <T> sourceClass) throws SQLException  ;
365 
366   /**
367    * Returns a Result for setting the XML value designated by this SQLXML instance.
368    * <p>
369    * The systemID of the Result is implementation dependent.
370    * <p>
371    * The SQL XML object becomes not writeable when this method is called and
372    * may also become not readable depending on implementation.
373    * <p>
374    * Note that SAX is a callback architecture and the returned
375    * SAXResult has a content handler assigned that will receive the 
376    * SAX events based on the contents of the XML.  Call the content
377    * handler with the contents of the XML document to assign the values.
378    * <pre>
379    *   SAXResult saxResult = sqlxml.setResult(SAXResult.class);
380    *   ContentHandler contentHandler = saxResult.getXMLReader().getContentHandler();
381    *   contentHandler.startDocument();
382    *   // set the XML elements and attributes into the result
383    *   contentHandler.endDocument();
384    * </pre>
385    * 
386    * @param resultClass The class of the result, or null.  
387    * If resultClass is null, a vendor specific Result implementation will be returned.
388    * The following classes are supported at a minimum:
389    * <pre>
390    *   javax.xml.transform.dom.DOMResult - returns a DOMResult
391    *   javax.xml.transform.sax.SAXResult - returns a SAXResult
392    *   javax.xml.transform.stax.StAXResult - returns a StAXResult
393    *   javax.xml.transform.stream.StreamResult - returns a StreamResult
394    * </pre>
395    * @return Returns a Result for setting the XML value.
396    * @throws SQLException if there is an error processing the XML value
397    *   or if this feature is not supported.
398    *   The getCause() method of the exception may provide a more detailed exception, for example,
399    *   if an XML parser exception occurs. 
400    *   An exception is thrown if the state is not writable.
401    * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
402    * this method
403    * @since 1.6
404    */
405   <T extends Result  > T setResult(Class  <T> resultClass) throws SQLException  ;
406 
407 }
408
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