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org.esau.ptarmigan.impl
Class GeneratorImpl  

java.lang.Object
  org.xml.sax.helpers.XMLFilterImpl
      org.esau.ptarmigan.impl.GeneratorImpl

All Implemented Interfaces:

org.xml.sax.ContentHandler, org.xml.sax.DTDHandler, org.xml.sax.EntityResolver, org.xml.sax.ErrorHandler, org.esau.ptarmigan.Generator, org.xml.sax.XMLFilter, org.xml.sax.XMLReader

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public final class GeneratorImpl

extends org.xml.sax.helpers.XMLFilterImpl

implements org.esau.ptarmigan.Generator

GeneratorImpl

From which the source is identified and which the parsers are launched

Instances of this class parse media files of different formats (mp3, ogg, pls, etc.) and generate SAX events describing the metadata of those files which can then be consumed, such as for data storage.

Those SAX events are typically used to build a Document which in turn is transformed to an object useable by the caller.

IMPLEMENTATION DETAILS

The algorithm used is designed for one-pass usage. It requires the use of a buffered stream where a marker can be set to sniff ahead for tags.

One at a time, give each parser a chance to sniff that buffer. The first one who returns sniff==true will own that position and immediately can parse data from it up to a limit.

NOTES

TODO: remove all references to specific parsers from the GeneratorImpl. Instead refer to them dynamically through StreamParser (ID3v2, Vorbis, etc.) and FileParser (ID3v1) interfaces. Place each parser in a jar and use a resource reference to identify it as a client parser.

Version:

$Revision: 1.7 $ $Date: 2002/09/24 02:51:17 $

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Field Summary
(package private) static int	DEFAULT_MAX_TAG_SIZE           the number of bytes to read from the start of a stream/file to identify which parser it requires
(package private) static org.xml.sax.Attributes	EMPTY_ATTRS
(package private) static boolean	EXCLUDE_DIGEST
(package private) static boolean	INCLUDE_DIGEST
(package private) static org.apache.commons.logging.Log	log           logging object
(package private)  java.util.List	m_binary_filters           the filters that work with binary streams
(package private)  boolean	m_configured           have the parsers been loaded?
(package private)  java.util.List	m_file_filters           the parsers that only work with files
(package private)  boolean	m_include_digest           should a digest be calculated for media?
(package private)  boolean	m_include_entries           should entries (perhaps many) be included in scanned playlists?
(package private)  MediaProperties	m_media_properties           details on the media, like data range and mime-type
(package private)  java.lang.String	m_parse_error           a holder for a stack trace in case a problem occurs; written out to xml
(package private)  int	m_read_limit
(package private)  java.lang.String	m_system_id           the unmodified system_id passed in as input
(package private)  java.io.File	m_system_id_file           if the source is a local file, here's its name
(package private)  java.net.URL	m_system_id_url           the system_id in URL form
(package private)  java.util.List	m_text_filters           the parsers that work with text streams
(package private) static java.lang.String	NS_PREFIX
(package private) static java.lang.String	NS_URI

 

Fields inherited from class org.xml.sax.helpers.XMLFilterImpl

 

Fields inherited from interface org.esau.ptarmigan.Generator

DEFAULT_INCLUDE_DIGEST, DEFAULT_INCLUDE_PLAYLIST_ENTRIES, DEFAULT_PROPERTY_READ_LIMIT, FEATURE_INCLUDE_DIGEST, FEATURE_INCLUDE_PLAYLIST_ENTRIES, PROPERTY_READ_LIMIT

 

Constructor Summary

GeneratorImpl()

 

Method Summary
(package private)  void	configure()           generator configuration TODO: configure this object from classnames specfied in an XML file, or via Jakarta Commons Discovery.
boolean	getFeature(java.lang.String name)           OVERRIDE Look up the value of a feature.
java.lang.Object	getProperty(java.lang.String name)           OVERRIDE Look up the value of a property.
(package private)  java.io.InputStream	getStream()           obtain an input stream from the system-id in the specified input source.
(package private)  java.lang.String	getTextMarker(byte[] sniff_bytes, int length)           read in the (text-based) marker, skipping any BOM for UTF-16 or UTF-8
(package private)  void	initSystemId(java.lang.String sid)           init the original system_id and the derived fields
void	parse(org.xml.sax.InputSource input)           OVERRIDE SAX-invoked parse If it's a file, attempt to parse the ID3v1 tag at the end of the file.
(package private)  void	parseBinaryStream(java.io.InputStream is)           Binary stream reading is constrained by the READ_LIMIT property.
(package private)  void	parseStream(java.io.InputStream is)           This is where the magic happens.
(package private)  void	parseTextStream(java.io.InputStream is)           Try to find a TEXT parser that can handle the stream, and if found let it consume it in its entireity.
(package private)  void	processFileSource()
void	resetData()           Reset data members for reuse
void	setContentHandler(org.xml.sax.ContentHandler handler)           OVERRIDE Set the content event handler.
void	setFeature(java.lang.String name, boolean value)           OVERRIDE Set the value of a feature.
void	setProperty(java.lang.String name, java.lang.Object value)           OVERRIDE Set the value of a property.
(package private)  void	write(java.lang.String key, java.util.Date date, boolean date_only)
(package private)  void	write(java.lang.String key, long value)
(package private)  void	write(java.lang.String key, java.lang.String value)
(package private)  void	write(java.lang.String key, java.lang.String value, org.xml.sax.Attributes attrs)
(package private)  void	writeFileProps()           write file-properties element and children
(package private)  void	writeLog()
(package private)  void	writeMediaDigest()
(package private)  void	writeMediaProps()           produce SAX events for the audio data-oriented metadata

 

Methods inherited from class org.xml.sax.helpers.XMLFilterImpl

characters, endDocument, endElement, endPrefixMapping, error, fatalError, getContentHandler, getDTDHandler, getEntityResolver, getErrorHandler, getParent, ignorableWhitespace, notationDecl, parse, processingInstruction, resolveEntity, setDocumentLocator, setDTDHandler, setEntityResolver, setErrorHandler, setParent, skippedEntity, startDocument, startElement, startPrefixMapping, unparsedEntityDecl, warning

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Methods inherited from interface org.xml.sax.XMLFilter

getParent, setParent

 

Methods inherited from interface org.xml.sax.XMLReader

getContentHandler, getDTDHandler, getEntityResolver, getErrorHandler, parse, setDTDHandler, setEntityResolver, setErrorHandler

 

Methods inherited from interface org.xml.sax.ContentHandler

characters, endDocument, endElement, endPrefixMapping, ignorableWhitespace, processingInstruction, setDocumentLocator, skippedEntity, startDocument, startElement, startPrefixMapping

 

Field Detail

m_parse_error

java.lang.String m_parse_error

a holder for a stack trace in case a problem occurs; written out to xml

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m_read_limit

int m_read_limit

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m_system_id

java.lang.String m_system_id

the unmodified system_id passed in as input

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m_configured

boolean m_configured

have the parsers been loaded?

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m_file_filters

java.util.List m_file_filters

the parsers that only work with files

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m_binary_filters

java.util.List m_binary_filters

the filters that work with binary streams

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m_text_filters

java.util.List m_text_filters

the parsers that work with text streams

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m_media_properties

MediaProperties m_media_properties

details on the media, like data range and mime-type

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m_system_id_url

java.net.URL m_system_id_url

the system_id in URL form

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m_system_id_file

java.io.File m_system_id_file

if the source is a local file, here's its name

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m_include_digest

boolean m_include_digest

should a digest be calculated for media?

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m_include_entries

boolean m_include_entries

should entries (perhaps many) be included in scanned playlists?

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INCLUDE_DIGEST

static final boolean INCLUDE_DIGEST

See Also:

Constant Field Values

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EXCLUDE_DIGEST

static final boolean EXCLUDE_DIGEST

See Also:

Constant Field Values

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NS_URI

static final java.lang.String NS_URI

See Also:

Constant Field Values

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NS_PREFIX

static final java.lang.String NS_PREFIX

See Also:

Constant Field Values

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EMPTY_ATTRS

static final org.xml.sax.Attributes EMPTY_ATTRS

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DEFAULT_MAX_TAG_SIZE

static final int DEFAULT_MAX_TAG_SIZE

the number of bytes to read from the start of a stream/file to identify which parser it requires

See Also:

Constant Field Values

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log

static org.apache.commons.logging.Log log

logging object

Constructor Detail

GeneratorImpl

public GeneratorImpl()

Method Detail

configure

void configure()
         throws java.io.IOException,
                org.xml.sax.SAXException

generator configuration TODO: configure this object from classnames specfied in an XML file, or via Jakarta Commons Discovery. TODO: use lazy loading TODO: where available, use file extension hints to determine which parser to invoke.

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parse

public void parse(org.xml.sax.InputSource input)
           throws java.io.IOException,
                  org.xml.sax.SAXException

OVERRIDE SAX-invoked parse If it's a file, attempt to parse the ID3v1 tag at the end of the file.

Specified by:

parse in interface org.xml.sax.XMLReader

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resetData

public void resetData()

Reset data members for reuse

Note that features and properties are NOT reset to defaults as they are usually set when the generator is created.

Specified by:

resetData in interface org.esau.ptarmigan.Generator

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setContentHandler

public void setContentHandler(org.xml.sax.ContentHandler handler)

OVERRIDE Set the content event handler.

Specified by:

setContentHandler in interface org.xml.sax.XMLReader

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getFeature

public boolean getFeature(java.lang.String name)
                   throws org.xml.sax.SAXNotRecognizedException,
                          org.xml.sax.SAXNotSupportedException

OVERRIDE Look up the value of a feature.

Specified by:

getFeature in interface org.xml.sax.XMLReader

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setFeature

public void setFeature(java.lang.String name,
                       boolean value)
                throws org.xml.sax.SAXNotRecognizedException,
                       org.xml.sax.SAXNotSupportedException

OVERRIDE Set the value of a feature.

Specified by:

setFeature in interface org.xml.sax.XMLReader

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getProperty

public java.lang.Object getProperty(java.lang.String name)
                             throws org.xml.sax.SAXNotRecognizedException,
                                    org.xml.sax.SAXNotSupportedException

OVERRIDE Look up the value of a property.

Specified by:

getProperty in interface org.xml.sax.XMLReader

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setProperty

public void setProperty(java.lang.String name,
                        java.lang.Object value)
                 throws org.xml.sax.SAXNotRecognizedException,
                        org.xml.sax.SAXNotSupportedException

OVERRIDE Set the value of a property.

Specified by:

setProperty in interface org.xml.sax.XMLReader

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getStream

java.io.InputStream getStream()
                        throws java.io.IOException

obtain an input stream from the system-id in the specified input source. Note that we explicitly don't buffer the stream here, as that is dealt with elsewhere.

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initSystemId

void initSystemId(java.lang.String sid)
            throws java.io.IOException

init the original system_id and the derived fields

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processFileSource

void processFileSource()
                 throws java.io.IOException,
                        org.xml.sax.SAXException

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parseStream

void parseStream(java.io.InputStream is)
           throws java.io.IOException,
                  org.xml.sax.SAXException

This is where the magic happens.

Extract metadata from a stream (text or binary) using the available parsers.

Parsing continues until a mime-type is assigned. TODO: some other flag perhaps?

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parseBinaryStream

void parseBinaryStream(java.io.InputStream is)
                 throws java.io.IOException,
                        java.text.ParseException,
                        org.xml.sax.SAXException

Binary stream reading is constrained by the READ_LIMIT property.

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parseTextStream

void parseTextStream(java.io.InputStream is)
               throws java.io.IOException,
                      java.text.ParseException,
                      org.xml.sax.SAXException

Try to find a TEXT parser that can handle the stream, and if found let it consume it in its entireity. The stream should be positioned at the start.

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getTextMarker

java.lang.String getTextMarker(byte[] sniff_bytes,
                               int length)
                         throws java.io.IOException,
                                java.text.ParseException

read in the (text-based) marker, skipping any BOM for UTF-16 or UTF-8

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writeFileProps

void writeFileProps()
              throws java.io.IOException,
                     org.xml.sax.SAXException

write file-properties element and children

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writeMediaProps

void writeMediaProps()
               throws java.io.IOException,
                      org.xml.sax.SAXException

produce SAX events for the audio data-oriented metadata

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writeMediaDigest

void writeMediaDigest()
                throws java.io.IOException,
                       org.xml.sax.SAXException

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writeLog

void writeLog()
        throws java.io.IOException,
               org.xml.sax.SAXException

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write

void write(java.lang.String key,
           java.lang.String value,
           org.xml.sax.Attributes attrs)
     throws org.xml.sax.SAXException

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write

void write(java.lang.String key,
           java.lang.String value)
     throws org.xml.sax.SAXException

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write

void write(java.lang.String key,
           long value)
     throws org.xml.sax.SAXException

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write

void write(java.lang.String key,
           java.util.Date date,
           boolean date_only)
     throws org.xml.sax.SAXException

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> esau >> ptarmigan >> [ impl overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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