burton 2004/04/22 23:11:57
Added: feedparser/src/java/org/apache/commons/feedparser/sax
RSSFeedParser.java
Log:
SAX support...
Revision Changes Path
1.1
jakarta-commons-sandbox/feedparser/src/java/org/apache/commons/feedparser/sax/RSSFeedParser.java
Index: RSSFeedParser.java
===================================================================
/*
* Copyright 1999,2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.feedparser.sax;
import org.apache.commons.feedparser.FeedParserListener;
import org.apache.commons.feedparser.FeedParserState;
import org.apache.commons.feedparser.FeedParserException;
import org.apache.commons.feedparser.FeedVersion;
import org.apache.commons.feedparser.MetaFeedParserListener;
import java.io.*;
import java.net.*;
import java.util.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;
/** *
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin A. Burton (burtonator)</a>
* @version $Id: RSSFeedParser.java,v 1.1 2004/04/23 06:11:57 burton Exp $
*/
public class RSSFeedParser extends BaseDefaultHandler {
public FeedParserListener listener = null;
boolean onItem = false;
HashMap properties = new HashMap();
FeedParserState state = new FeedParserState();
static HashSet RSS_NAMESPACES = new HashSet();
static HashSet RDF_NAMESPACES = new HashSet();
static HashSet MOD_CONTENT_NAMESPACES = new HashSet();
static {
RSS_NAMESPACES.add( "http://purl.org/rss/1.0/"; );
RDF_NAMESPACES.add( "http://www.w3.org/1999/02/22-rdf-syntax-ns#"; );
MOD_CONTENT_NAMESPACES.add( "http://purl.org/rss/1.0/modules/content/"; );
}
/**
*
* Create a new <code>RSSFeedParser</code> instance.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public RSSFeedParser() {
super( "FIXME" );
this.parser = this;
setNext( new ChannelTemplate( this ) );
}
public void startDocument() throws SAXException {
try {
FeedVersion v = new FeedVersion();
v.isRSS = true;
listener.onFeedVersion( v );
listener.init();
} catch ( FeedParserException f ) {
throw new SAXException( f );
}
}
public void endDocument() throws SAXException {
try {
listener.finished();
} catch ( FeedParserException f ) {
throw new SAXException( f );
}
}
/**
* Match rss:channel
*/
class ChannelTemplate extends BaseDefaultHandler {
public ChannelTemplate( RSSFeedParser parser ) {
super( "channel", parser.RSS_NAMESPACES, parser );
setNext( new URLTemplate( parser ) );
}
public void beginFeedElement() throws FeedParserException {
parser.listener.onChannel( parser.state,
getProperty( "title" ),
getProperty( "link" ),
getProperty( "description" ) );
}
public void endFeedElement() throws FeedParserException {
parser.listener.onChannelEnd();
}
}
/**
* Match rss:url for images/etc
*/
class URLTemplate extends BaseDefaultHandler {
public URLTemplate( RSSFeedParser parser ) {
super( "url", parser.RSS_NAMESPACES, parser );
setNext( new ModContentTemplate( parser ) );
//this.setNext( new RDFValueTemplate( parser ) );
}
}
/**
* Match the rdf:value for mod_content
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
class ModContentTemplate extends BaseDefaultHandler {
public ModContentTemplate( RSSFeedParser parser ) {
super( "items", parser.MOD_CONTENT_NAMESPACES, parser );
this.setNext( new RDFValueTemplate( parser ) );
}
}
/**
* Match the rdf:value for mod_content
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
class RDFValueTemplate extends BaseDefaultHandler {
public RDFValueTemplate( RSSFeedParser parser ) {
super( "value", parser.RDF_NAMESPACES, parser );
this.setIncludeContent( true );
this.setNext( new RSSImageFeedParser( parser ) );
}
public void endFeedElement() throws FeedParserException {
System.out.println( " FIXME: (debug): " + getProperty( "value" ) );
}
}
}
class RSSImageFeedParser extends BaseDefaultHandler {
public RSSImageFeedParser( RSSFeedParser parser ) {
super( "image", parser.RSS_NAMESPACES, parser );
setNext( new RSSItemFeedParser( parser ) );
}
public void beginFeedElement() throws FeedParserException {
parser.listener.onImage( parser.state,
getProperty( "title" ),
getProperty( "link" ),
getProperty( "url" ) );
}
public void endFeedElement() throws FeedParserException {
parser.listener.onImageEnd();
}
}
class RSSItemFeedParser extends BaseDefaultHandler {
public RSSItemFeedParser( RSSFeedParser parser ) {
super( "item", parser );
this.namespaces = parser.RSS_NAMESPACES;
setNext( new RSSTitleFeedParser( parser ) );
}
public void beginFeedElement() throws FeedParserException {
parser.listener.onItem( parser.state,
getProperty( "title" ),
getProperty( "link" ),
getProperty( "description" ),
null );
}
public void endFeedElement() throws FeedParserException {
parser.listener.onItemEnd();
}
}
class RSSTitleFeedParser extends BaseDefaultHandler {
public RSSTitleFeedParser( RSSFeedParser parser ) {
super( "title", parser );
setNext( new RSSLinkFeedParser( parser ) );
}
}
class RSSLinkFeedParser extends BaseDefaultHandler {
public RSSLinkFeedParser( RSSFeedParser parser ) {
super( "link", parser );
setNext( new RSSDescriptionFeedParser( parser ) );
}
}
class RSSDescriptionFeedParser extends BaseDefaultHandler {
public RSSDescriptionFeedParser( RSSFeedParser parser ) {
super( "description", parser );
}
}
/**
* dc:subject support
*/
class RSSDcSubjectFeedParser extends BaseDefaultHandler {
//MetaFeedParserListener metadataListener= null;
public RSSDcSubjectFeedParser( RSSFeedParser parser ) {
super( "subject", parser );
}
public void beginFeedElement() {
//only if it's dc:subject
//listener.onSubject( parser.state, parser.getProperty( "subject" ) );
}
public void endFeedElement() {
}
}
class BaseDefaultHandler extends DefaultHandler {
public static int STRING_BUFFER_CAPACITY = 100000;
//BUG: this will break on nested code:
// <foo>
// <foo>
//
// </foo>
//
// </foo>
// won't be smart enough to realize it's nested
/**
* The local name of the element
*/
private String local = null;
//FIXME: move to a FastStringBuffer that's not synchronized.
private StringBuffer buff = null;
private boolean onElement = false;
private boolean includeContent = false;
BaseDefaultHandler next = null;
FeedParserListener listener = null;
RSSFeedParser parser = null;
static HashMap nsPrefixMapping = new HashMap();
/**
* Store a hashset of namespaces that the given URL supports.
*
*/
HashSet namespaces = null;
public BaseDefaultHandler( String local ) {
this.local = local;
}
public BaseDefaultHandler( String local, RSSFeedParser parser ) {
this.local = local;
this.parser = parser;
}
public BaseDefaultHandler( String local,
HashSet namespaces,
RSSFeedParser parser ) {
this.local = local;
this.namespaces = namespaces;
this.parser = parser;
}
/**
* If true we include the RAW XML content from the parser.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public void setIncludeContent( boolean includeContent ) {
this.includeContent = includeContent;
}
/**
* Set the next template to process in this chain.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public void setNext( BaseDefaultHandler next ) {
this.next = next;
}
/**
* Return the value of character data forfor the element.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public String toString() {
if ( buff == null )
return null;
if ( buff.length() == 0 )
return null;
return buff.toString();
}
/**
* Return true if the namespace is valid and this class is handling the
* given element name
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
boolean isLocal( String namespace, String local ) {
//wee if we need to test forfor namespaces
if ( namespace != null && namespaces != null && ! namespaces.contains(
namespace ) )
return false;
return this.local.equals( local );
}
/**
* Get the value of a string property we found whilewhile parsing
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public String getProperty( String name ) {
return (String)parser.properties.get( name );
}
public boolean getBoolean( String name ) {
return "true".equals( getProperty( name ) );
}
/**
* Method to call when we're finished processing this element but BEFORE
* processing of the next element in the chain.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public void beginFeedElement() throws FeedParserException {}
/**
* Method to call when we're finished processing this element but AFTER
* processing of the next element in the chain.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public void endFeedElement() throws FeedParserException {}
private boolean includeContentPrefix( String namespace ) {
if ( namespace != null ) {
String prefix = (String)nsPrefixMapping.get( namespace );
if ( prefix != null ) {
buff.append( prefix );
buff.append( ":" );
return true;
}
}
return false;
}
// **** SAX DefaultHandler **************************************************
/**
* Keep track of namespaces.
*
* @author <a href="mailto:[EMAIL PROTECTED]">Kevin Burton</a>
*/
public void startPrefixMapping( String prefix,
String namespace ) throws SAXException {
if ( prefix != null && ! "".equals( prefix ) ) {
//System.out.println( namespace + " -> " + prefix );
nsPrefixMapping.put( namespace, prefix );
}
}
//FIXME: it might be possible to call an item again without a member and the
//value from the LAST item is used... this needs to be a fatal error and we
//need to clear ...
public void startElement( String namespace,
String local,
String qName,
Attributes attributes ) throws SAXException {
if ( isLocal( namespace, local ) ) {
//FIXME: is there a more efficient way to clear a buffer than this?
//FIXME: also only do this ifif it's necessary and content has
//actually been added. This will save some performance.
//buff = new StringBuffer( STRING_BUFFER_CAPACITY );
//buff = new StringBuffer( 1000 );
if ( buff == null ) {
buff = new StringBuffer( 1000 );
} else {
buff.setLength( 0 );
}
onElement = true;
}
if ( next != null )
next.startElement( namespace, local, qName, attributes );
if ( includeContent && onElement ) {
buff.append( "<" );
boolean hasPrefix = includeContentPrefix( namespace );
buff.append( local );
if ( ! hasPrefix && namespace != null ) {
buff.append( " xmlns=\"" );
buff.append( namespace );
buff.append( "\"" );
}
//now include attributes
int length = attributes.getLength();
for ( int i = 0; i < length; ++i ) {
buff.append( " " );
buff.append( attributes.getQName( i ) );
buff.append( "=" );
buff.append( "\"" );
buff.append( attributes.getValue( i ) );
buff.append( "\"" );
}
buff.append( ">" );
}
}
public void characters( char[] ch,
int start,
int length ) throws SAXException {
if ( onElement ) {
buff.append( ch, start, length );
}
if ( next != null )
next.characters( ch, start, length );
}
public void endElement( String namespace,
String local,
String qName ) throws SAXException {
try {
if ( isLocal( namespace, local ) ) {
onElement = false;
parser.properties.put( local, toString() );
beginFeedElement();
}
if ( next != null )
next.endElement( namespace, local, qName );
if ( isLocal( namespace, local ) )
endFeedElement();
if ( includeContent && onElement ) {
buff.append( "</" );
includeContentPrefix( namespace );
buff.append( local );
buff.append( ">" );
}
} catch ( FeedParserException fpe ) {
throw new SAXException( fpe );
}
}
}
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