375 lines
15 KiB
Java
375 lines
15 KiB
Java
// ContentHandler.java - handle main document content.
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// Written by David Megginson, sax@megginson.com
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// NO WARRANTY! This class is in the public domain.
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// $Id: ContentHandler.java,v 1.1 2000/10/02 02:43:16 sboag Exp $
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package org.xml.sax;
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/**
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* Receive notification of the logical content of a document.
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*
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* <blockquote>
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* <em>This module, both source code and documentation, is in the
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* Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
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* </blockquote>
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*
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* <p>This is the main interface that most SAX applications
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* implement: if the application needs to be informed of basic parsing
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* events, it implements this interface and registers an instance with
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* the SAX parser using the {@link org.xml.sax.XMLReader#setContentHandler
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* setContentHandler} method. The parser uses the instance to report
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* basic document-related events like the start and end of elements
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* and character data.</p>
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*
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* <p>The order of events in this interface is very important, and
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* mirrors the order of information in the document itself. For
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* example, all of an element's content (character data, processing
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* instructions, and/or subelements) will appear, in order, between
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* the startElement event and the corresponding endElement event.</p>
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*
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* <p>This interface is similar to the now-deprecated SAX 1.0
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* DocumentHandler interface, but it adds support for Namespaces
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* and for reporting skipped entities (in non-validating XML
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* processors).</p>
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*
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* <p>Implementors should note that there is also a Java class
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* {@link java.net.ContentHandler ContentHandler} in the java.net
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* package; that means that it's probably a bad idea to do</p>
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*
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* <blockquote>
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* import java.net.*;
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* import org.xml.sax.*;
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* </blockquote>
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*
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* <p>In fact, "import ...*" is usually a sign of sloppy programming
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* anyway, so the user should consider this a feature rather than a
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* bug.</p>
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*
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* @since SAX 2.0
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* @author David Megginson,
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* <a href="mailto:sax@megginson.com">sax@megginson.com</a>
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* @version 2.0
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* @see org.xml.sax.XMLReader
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* @see org.xml.sax.DTDHandler
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* @see org.xml.sax.ErrorHandler
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*/
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public interface ContentHandler
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{
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/**
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* Receive an object for locating the origin of SAX document events.
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*
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* <p>SAX parsers are strongly encouraged (though not absolutely
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* required) to supply a locator: if it does so, it must supply
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* the locator to the application by invoking this method before
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* invoking any of the other methods in the ContentHandler
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* interface.</p>
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*
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* <p>The locator allows the application to determine the end
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* position of any document-related event, even if the parser is
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* not reporting an error. Typically, the application will
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* use this information for reporting its own errors (such as
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* character content that does not match an application's
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* business rules). The information returned by the locator
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* is probably not sufficient for use with a search engine.</p>
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*
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* <p>Note that the locator will return correct information only
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* during the invocation of the events in this interface. The
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* application should not attempt to use it at any other time.</p>
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*
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* @param locator An object that can return the location of
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* any SAX document event.
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* @see org.xml.sax.Locator
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*/
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public void setDocumentLocator (Locator locator);
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/**
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* Receive notification of the beginning of a document.
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*
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* <p>The SAX parser will invoke this method only once, before any
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* other methods in this interface or in {@link org.xml.sax.DTDHandler
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* DTDHandler} (except for {@link #setDocumentLocator
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* setDocumentLocator}).</p>
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*
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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* @see #endDocument
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*/
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public void startDocument ()
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throws SAXException;
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/**
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* Receive notification of the end of a document.
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*
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* <p>The SAX parser will invoke this method only once, and it will
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* be the last method invoked during the parse. The parser shall
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* not invoke this method until it has either abandoned parsing
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* (because of an unrecoverable error) or reached the end of
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* input.</p>
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*
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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* @see #startDocument
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*/
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public void endDocument()
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throws SAXException;
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/**
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* Begin the scope of a prefix-URI Namespace mapping.
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*
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* <p>The information from this event is not necessary for
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* normal Namespace processing: the SAX XML reader will
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* automatically replace prefixes for element and attribute
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* names when the <code>http://xml.org/sax/features/namespaces</code>
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* feature is <var>true</var> (the default).</p>
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*
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* <p>There are cases, however, when applications need to
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* use prefixes in character data or in attribute values,
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* where they cannot safely be expanded automatically; the
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* start/endPrefixMapping event supplies the information
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* to the application to expand prefixes in those contexts
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* itself, if necessary.</p>
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*
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* <p>Note that start/endPrefixMapping events are not
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* guaranteed to be properly nested relative to each-other:
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* all startPrefixMapping events will occur before the
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* corresponding {@link #startElement startElement} event,
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* and all {@link #endPrefixMapping endPrefixMapping}
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* events will occur after the corresponding {@link #endElement
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* endElement} event, but their order is not otherwise
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* guaranteed.</p>
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*
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* <p>There should never be start/endPrefixMapping events for the
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* "xml" prefix, since it is predeclared and immutable.</p>
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*
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* @param prefix The Namespace prefix being declared.
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* @param uri The Namespace URI the prefix is mapped to.
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* @exception org.xml.sax.SAXException The client may throw
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* an exception during processing.
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* @see #endPrefixMapping
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* @see #startElement
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*/
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public void startPrefixMapping (String prefix, String uri)
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throws SAXException;
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/**
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* End the scope of a prefix-URI mapping.
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*
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* <p>See {@link #startPrefixMapping startPrefixMapping} for
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* details. This event will always occur after the corresponding
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* {@link #endElement endElement} event, but the order of
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* {@link #endPrefixMapping endPrefixMapping} events is not otherwise
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* guaranteed.</p>
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*
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* @param prefix The prefix that was being mapping.
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* @exception org.xml.sax.SAXException The client may throw
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* an exception during processing.
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* @see #startPrefixMapping
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* @see #endElement
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*/
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public void endPrefixMapping (String prefix)
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throws SAXException;
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/**
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* Receive notification of the beginning of an element.
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*
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* <p>The Parser will invoke this method at the beginning of every
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* element in the XML document; there will be a corresponding
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* {@link #endElement endElement} event for every startElement event
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* (even when the element is empty). All of the element's content will be
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* reported, in order, before the corresponding endElement
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* event.</p>
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*
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* <p>This event allows up to three name components for each
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* element:</p>
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*
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* <ol>
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* <li>the Namespace URI;</li>
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* <li>the local name; and</li>
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* <li>the qualified (prefixed) name.</li>
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* </ol>
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*
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* <p>Any or all of these may be provided, depending on the
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* values of the <var>http://xml.org/sax/features/namespaces</var>
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* and the <var>http://xml.org/sax/features/namespace-prefixes</var>
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* properties:</p>
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*
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* <ul>
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* <li>the Namespace URI and local name are required when
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* the namespaces property is <var>true</var> (the default), and are
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* optional when the namespaces property is <var>false</var> (if one is
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* specified, both must be);</li>
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* <li>the qualified name is required when the namespace-prefixes property
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* is <var>true</var>, and is optional when the namespace-prefixes property
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* is <var>false</var> (the default).</li>
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* </ul>
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*
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* <p>Note that the attribute list provided will contain only
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* attributes with explicit values (specified or defaulted):
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* #IMPLIED attributes will be omitted. The attribute list
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* will contain attributes used for Namespace declarations
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* (xmlns* attributes) only if the
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* <code>http://xml.org/sax/features/namespace-prefixes</code>
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* property is true (it is false by default, and support for a
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* true value is optional).</p>
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*
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* @param uri The Namespace URI, or the empty string if the
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* element has no Namespace URI or if Namespace
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* processing is not being performed.
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* @param localName The local name (without prefix), or the
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* empty string if Namespace processing is not being
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* performed.
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* @param qName The qualified name (with prefix), or the
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* empty string if qualified names are not available.
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* @param atts The attributes attached to the element. If
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* there are no attributes, it shall be an empty
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* Attributes object.
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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* @see #endElement
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* @see org.xml.sax.Attributes
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*/
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public void startElement (String namespaceURI, String localName,
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String qName, Attributes atts)
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throws SAXException;
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/**
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* Receive notification of the end of an element.
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*
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* <p>The SAX parser will invoke this method at the end of every
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* element in the XML document; there will be a corresponding
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* {@link #startElement startElement} event for every endElement
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* event (even when the element is empty).</p>
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*
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* <p>For information on the names, see startElement.</p>
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*
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* @param uri The Namespace URI, or the empty string if the
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* element has no Namespace URI or if Namespace
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* processing is not being performed.
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* @param localName The local name (without prefix), or the
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* empty string if Namespace processing is not being
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* performed.
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* @param qName The qualified XML 1.0 name (with prefix), or the
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* empty string if qualified names are not available.
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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*/
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public void endElement (String namespaceURI, String localName,
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String qName)
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throws SAXException;
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/**
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* Receive notification of character data.
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*
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* <p>The Parser will call this method to report each chunk of
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* character data. SAX parsers may return all contiguous character
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* data in a single chunk, or they may split it into several
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* chunks; however, all of the characters in any single event
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* must come from the same external entity so that the Locator
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* provides useful information.</p>
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*
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* <p>The application must not attempt to read from the array
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* outside of the specified range.</p>
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*
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* <p>Note that some parsers will report whitespace in element
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* content using the {@link #ignorableWhitespace ignorableWhitespace}
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* method rather than this one (validating parsers <em>must</em>
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* do so).</p>
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*
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* @param ch The characters from the XML document.
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* @param start The start position in the array.
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* @param length The number of characters to read from the array.
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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* @see #ignorableWhitespace
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* @see org.xml.sax.Locator
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*/
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public void characters (char ch[], int start, int length)
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throws SAXException;
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/**
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* Receive notification of ignorable whitespace in element content.
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*
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* <p>Validating Parsers must use this method to report each chunk
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* of whitespace in element content (see the W3C XML 1.0 recommendation,
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* section 2.10): non-validating parsers may also use this method
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* if they are capable of parsing and using content models.</p>
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*
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* <p>SAX parsers may return all contiguous whitespace in a single
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* chunk, or they may split it into several chunks; however, all of
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* the characters in any single event must come from the same
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* external entity, so that the Locator provides useful
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* information.</p>
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*
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* <p>The application must not attempt to read from the array
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* outside of the specified range.</p>
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*
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* @param ch The characters from the XML document.
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* @param start The start position in the array.
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* @param length The number of characters to read from the array.
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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* @see #characters
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*/
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public void ignorableWhitespace (char ch[], int start, int length)
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throws SAXException;
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/**
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* Receive notification of a processing instruction.
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*
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* <p>The Parser will invoke this method once for each processing
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* instruction found: note that processing instructions may occur
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* before or after the main document element.</p>
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*
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* <p>A SAX parser must never report an XML declaration (XML 1.0,
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* section 2.8) or a text declaration (XML 1.0, section 4.3.1)
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* using this method.</p>
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*
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* @param target The processing instruction target.
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* @param data The processing instruction data, or null if
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* none was supplied. The data does not include any
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* whitespace separating it from the target.
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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*/
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public void processingInstruction (String target, String data)
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throws SAXException;
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/**
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* Receive notification of a skipped entity.
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*
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* <p>The Parser will invoke this method once for each entity
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* skipped. Non-validating processors may skip entities if they
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* have not seen the declarations (because, for example, the
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* entity was declared in an external DTD subset). All processors
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* may skip external entities, depending on the values of the
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* <code>http://xml.org/sax/features/external-general-entities</code>
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* and the
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* <code>http://xml.org/sax/features/external-parameter-entities</code>
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* properties.</p>
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*
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* @param name The name of the skipped entity. If it is a
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* parameter entity, the name will begin with '%', and if
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* it is the external DTD subset, it will be the string
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* "[dtd]".
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* @exception org.xml.sax.SAXException Any SAX exception, possibly
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* wrapping another exception.
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*/
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public void skippedEntity (String name)
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throws SAXException;
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}
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// end of ContentHandler.java
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