Java tutorial
/* * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.sql; import java.io.InputStream; import java.io.OutputStream; import java.io.Reader; import java.io.Writer; import javax.xml.transform.Result; import javax.xml.transform.Source; /** * The mapping in the JavaTM programming language for the SQL XML type. * XML is a built-in type that stores an XML value * as a column value in a row of a database table. * By default drivers implement an SQLXML object as * a logical pointer to the XML data * rather than the data itself. * An SQLXML object is valid for the duration of the transaction in which it was created. * <p> * The SQLXML interface provides methods for accessing the XML value * as a String, a Reader or Writer, or as a Stream. The XML value * may also be accessed through a Source or set as a Result, which * are used with XML Parser APIs such as DOM, SAX, and StAX, as * well as with XSLT transforms and XPath evaluations. * <p> * Methods in the interfaces ResultSet, CallableStatement, and PreparedStatement, * such as getSQLXML allow a programmer to access an XML value. * In addition, this interface has methods for updating an XML value. * <p> * The XML value of the SQLXML instance may be obtained as a BinaryStream using * <pre> * SQLXML sqlxml = resultSet.getSQLXML(column); * InputStream binaryStream = sqlxml.getBinaryStream(); * </pre> * For example, to parse an XML value with a DOM parser: * <pre> * DocumentBuilder parser = DocumentBuilderFactory.newInstance().newDocumentBuilder(); * Document result = parser.parse(binaryStream); * </pre> * or to parse an XML value with a SAX parser to your handler: * <pre> * SAXParser parser = SAXParserFactory.newInstance().newSAXParser(); * parser.parse(binaryStream, myHandler); * </pre> * or to parse an XML value with a StAX parser: * <pre> * XMLInputFactory factory = XMLInputFactory.newInstance(); * XMLStreamReader streamReader = factory.createXMLStreamReader(binaryStream); * </pre> * <p> * Because databases may use an optimized representation for the XML, * accessing the value through getSource() and * setResult() can lead to improved processing performance * without serializing to a stream representation and parsing the XML. * <p> * For example, to obtain a DOM Document Node: * <pre> * DOMSource domSource = sqlxml.getSource(DOMSource.class); * Document document = (Document) domSource.getNode(); * </pre> * or to set the value to a DOM Document Node to myNode: * <pre> * DOMResult domResult = sqlxml.setResult(DOMResult.class); * domResult.setNode(myNode); * </pre> * or, to send SAX events to your handler: * <pre> * SAXSource saxSource = sqlxml.getSource(SAXSource.class); * XMLReader xmlReader = saxSource.getXMLReader(); * xmlReader.setContentHandler(myHandler); * xmlReader.parse(saxSource.getInputSource()); * </pre> * or, to set the result value from SAX events: * <pre> * SAXResult saxResult = sqlxml.setResult(SAXResult.class); * ContentHandler contentHandler = saxResult.getHandler(); * contentHandler.startDocument(); * // set the XML elements and attributes into the result * contentHandler.endDocument(); * </pre> * or, to obtain StAX events: * <pre> * StAXSource staxSource = sqlxml.getSource(StAXSource.class); * XMLStreamReader streamReader = staxSource.getXMLStreamReader(); * </pre> * or, to set the result value from StAX events: * <pre> * StAXResult staxResult = sqlxml.setResult(StAXResult.class); * XMLStreamWriter streamWriter = staxResult.getXMLStreamWriter(); * </pre> * or, to perform XSLT transformations on the XML value using the XSLT in xsltFile * output to file resultFile: * <pre> * File xsltFile = new File("a.xslt"); * File myFile = new File("result.xml"); * Transformer xslt = TransformerFactory.newInstance().newTransformer(new StreamSource(xsltFile)); * Source source = sqlxml.getSource(null); * Result result = new StreamResult(myFile); * xslt.transform(source, result); * </pre> * or, to evaluate an XPath expression on the XML value: * <pre> * XPath xpath = XPathFactory.newInstance().newXPath(); * DOMSource domSource = sqlxml.getSource(DOMSource.class); * Document document = (Document) domSource.getNode(); * String expression = "/foo/@bar"; * String barValue = xpath.evaluate(expression, document); * </pre> * To set the XML value to be the result of an XSLT transform: * <pre> * File sourceFile = new File("source.xml"); * Transformer xslt = TransformerFactory.newInstance().newTransformer(new StreamSource(xsltFile)); * Source streamSource = new StreamSource(sourceFile); * Result result = sqlxml.setResult(null); * xslt.transform(streamSource, result); * </pre> * Any Source can be transformed to a Result using the identity transform * specified by calling newTransformer(): * <pre> * Transformer identity = TransformerFactory.newInstance().newTransformer(); * Source source = sqlxml.getSource(null); * File myFile = new File("result.xml"); * Result result = new StreamResult(myFile); * identity.transform(source, result); * </pre> * To write the contents of a Source to standard output: * <pre> * Transformer identity = TransformerFactory.newInstance().newTransformer(); * Source source = sqlxml.getSource(null); * Result result = new StreamResult(System.out); * identity.transform(source, result); * </pre> * To create a DOMSource from a DOMResult: * <pre> * DOMSource domSource = new DOMSource(domResult.getNode()); * </pre> * <p> * Incomplete or invalid XML values may cause an SQLException when * set or the exception may occur when execute() occurs. All streams * must be closed before execute() occurs or an SQLException will be thrown. * <p> * Reading and writing XML values to or from an SQLXML object can happen at most once. * The conceptual states of readable and not readable determine if one * of the reading APIs will return a value or throw an exception. * The conceptual states of writable and not writable determine if one * of the writing APIs will set a value or throw an exception. * <p> * The state moves from readable to not readable once free() or any of the * reading APIs are called: getBinaryStream(), getCharacterStream(), getSource(), and getString(). * Implementations may also change the state to not writable when this occurs. * <p> * The state moves from writable to not writable once free() or any of the * writing APIs are called: setBinaryStream(), setCharacterStream(), setResult(), and setString(). * Implementations may also change the state to not readable when this occurs. * * <p> * All methods on the <code>SQLXML</code> interface must be fully implemented if the * JDBC driver supports the data type. * * @see javax.xml.parsers * @see javax.xml.stream * @see javax.xml.transform * @see javax.xml.xpath * @since 1.6 */ public interface SQLXML { /** * This method closes this object and releases the resources that it held. * The SQL XML object becomes invalid and neither readable or writable * when this method is called. * * After <code>free</code> has been called, any attempt to invoke a * method other than <code>free</code> will result in a <code>SQLException</code> * being thrown. If <code>free</code> is called multiple times, the subsequent * calls to <code>free</code> are treated as a no-op. * @throws SQLException if there is an error freeing the XML value. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ void free() throws SQLException; /** * Retrieves the XML value designated by this SQLXML instance as a stream. * The bytes of the input stream are interpreted according to appendix F of the XML 1.0 specification. * The behavior of this method is the same as ResultSet.getBinaryStream() * when the designated column of the ResultSet has a type java.sql.Types of SQLXML. * <p> * The SQL XML object becomes not readable when this method is called and * may also become not writable depending on implementation. * * @return a stream containing the XML data. * @throws SQLException if there is an error processing the XML value. * An exception is thrown if the state is not readable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ InputStream getBinaryStream() throws SQLException; /** * Retrieves a stream that can be used to write the XML value that this SQLXML instance represents. * The stream begins at position 0. * The bytes of the stream are interpreted according to appendix F of the XML 1.0 specification * The behavior of this method is the same as ResultSet.updateBinaryStream() * when the designated column of the ResultSet has a type java.sql.Types of SQLXML. * <p> * The SQL XML object becomes not writable when this method is called and * may also become not readable depending on implementation. * * @return a stream to which data can be written. * @throws SQLException if there is an error processing the XML value. * An exception is thrown if the state is not writable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ OutputStream setBinaryStream() throws SQLException; /** * Retrieves the XML value designated by this SQLXML instance as a java.io.Reader object. * The format of this stream is defined by org.xml.sax.InputSource, * where the characters in the stream represent the unicode code points for * XML according to section 2 and appendix B of the XML 1.0 specification. * Although an encoding declaration other than unicode may be present, * the encoding of the stream is unicode. * The behavior of this method is the same as ResultSet.getCharacterStream() * when the designated column of the ResultSet has a type java.sql.Types of SQLXML. * <p> * The SQL XML object becomes not readable when this method is called and * may also become not writable depending on implementation. * * @return a stream containing the XML data. * @throws SQLException if there is an error processing the XML value. * The getCause() method of the exception may provide a more detailed exception, for example, * if the stream does not contain valid characters. * An exception is thrown if the state is not readable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ Reader getCharacterStream() throws SQLException; /** * Retrieves a stream to be used to write the XML value that this SQLXML instance represents. * The format of this stream is defined by org.xml.sax.InputSource, * where the characters in the stream represent the unicode code points for * XML according to section 2 and appendix B of the XML 1.0 specification. * Although an encoding declaration other than unicode may be present, * the encoding of the stream is unicode. * The behavior of this method is the same as ResultSet.updateCharacterStream() * when the designated column of the ResultSet has a type java.sql.Types of SQLXML. * <p> * The SQL XML object becomes not writable when this method is called and * may also become not readable depending on implementation. * * @return a stream to which data can be written. * @throws SQLException if there is an error processing the XML value. * The getCause() method of the exception may provide a more detailed exception, for example, * if the stream does not contain valid characters. * An exception is thrown if the state is not writable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ Writer setCharacterStream() throws SQLException; /** * Returns a string representation of the XML value designated by this SQLXML instance. * The format of this String is defined by org.xml.sax.InputSource, * where the characters in the stream represent the unicode code points for * XML according to section 2 and appendix B of the XML 1.0 specification. * Although an encoding declaration other than unicode may be present, * the encoding of the String is unicode. * The behavior of this method is the same as ResultSet.getString() * when the designated column of the ResultSet has a type java.sql.Types of SQLXML. * <p> * The SQL XML object becomes not readable when this method is called and * may also become not writable depending on implementation. * * @return a string representation of the XML value designated by this SQLXML instance. * @throws SQLException if there is an error processing the XML value. * The getCause() method of the exception may provide a more detailed exception, for example, * if the stream does not contain valid characters. * An exception is thrown if the state is not readable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ String getString() throws SQLException; /** * Sets the XML value designated by this SQLXML instance to the given String representation. * The format of this String is defined by org.xml.sax.InputSource, * where the characters in the stream represent the unicode code points for * XML according to section 2 and appendix B of the XML 1.0 specification. * Although an encoding declaration other than unicode may be present, * the encoding of the String is unicode. * The behavior of this method is the same as ResultSet.updateString() * when the designated column of the ResultSet has a type java.sql.Types of SQLXML. * <p> * The SQL XML object becomes not writable when this method is called and * may also become not readable depending on implementation. * * @param value the XML value * @throws SQLException if there is an error processing the XML value. * The getCause() method of the exception may provide a more detailed exception, for example, * if the stream does not contain valid characters. * An exception is thrown if the state is not writable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ void setString(String value) throws SQLException; /** * Returns a Source for reading the XML value designated by this SQLXML instance. * Sources are used as inputs to XML parsers and XSLT transformers. * <p> * Sources for XML parsers will have namespace processing on by default. * The systemID of the Source is implementation dependent. * <p> * The SQL XML object becomes not readable when this method is called and * may also become not writable depending on implementation. * <p> * Note that SAX is a callback architecture, so a returned * SAXSource should then be set with a content handler that will * receive the SAX events from parsing. The content handler * will receive callbacks based on the contents of the XML. * <pre> * SAXSource saxSource = sqlxml.getSource(SAXSource.class); * XMLReader xmlReader = saxSource.getXMLReader(); * xmlReader.setContentHandler(myHandler); * xmlReader.parse(saxSource.getInputSource()); * </pre> * * @param <T> the type of the class modeled by this Class object * @param sourceClass The class of the source, or null. * If the class is null, a vendor specific Source implementation will be returned. * The following classes are supported at a minimum: * <pre> * javax.xml.transform.dom.DOMSource - returns a DOMSource * javax.xml.transform.sax.SAXSource - returns a SAXSource * javax.xml.transform.stax.StAXSource - returns a StAXSource * javax.xml.transform.stream.StreamSource - returns a StreamSource * </pre> * @return a Source for reading the XML value. * @throws SQLException if there is an error processing the XML value * or if this feature is not supported. * The getCause() method of the exception may provide a more detailed exception, for example, * if an XML parser exception occurs. * An exception is thrown if the state is not readable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ <T extends Source> T getSource(Class<T> sourceClass) throws SQLException; /** * Returns a Result for setting the XML value designated by this SQLXML instance. * <p> * The systemID of the Result is implementation dependent. * <p> * The SQL XML object becomes not writable when this method is called and * may also become not readable depending on implementation. * <p> * Note that SAX is a callback architecture and the returned * SAXResult has a content handler assigned that will receive the * SAX events based on the contents of the XML. Call the content * handler with the contents of the XML document to assign the values. * <pre> * SAXResult saxResult = sqlxml.setResult(SAXResult.class); * ContentHandler contentHandler = saxResult.getXMLReader().getContentHandler(); * contentHandler.startDocument(); * // set the XML elements and attributes into the result * contentHandler.endDocument(); * </pre> * * @param <T> the type of the class modeled by this Class object * @param resultClass The class of the result, or null. * If resultClass is null, a vendor specific Result implementation will be returned. * The following classes are supported at a minimum: * <pre> * javax.xml.transform.dom.DOMResult - returns a DOMResult * javax.xml.transform.sax.SAXResult - returns a SAXResult * javax.xml.transform.stax.StAXResult - returns a StAXResult * javax.xml.transform.stream.StreamResult - returns a StreamResult * </pre> * @return Returns a Result for setting the XML value. * @throws SQLException if there is an error processing the XML value * or if this feature is not supported. * The getCause() method of the exception may provide a more detailed exception, for example, * if an XML parser exception occurs. * An exception is thrown if the state is not writable. * @exception SQLFeatureNotSupportedException if the JDBC driver does not support * this method * @since 1.6 */ <T extends Result> T setResult(Class<T> resultClass) throws SQLException; }