org.dspace.app.xmlui.cocoon
Class BitstreamReader

java.lang.Object
  org.apache.cocoon.util.AbstractLogEnabled
      org.apache.cocoon.reading.AbstractReader
          org.dspace.app.xmlui.cocoon.BitstreamReader

All Implemented Interfaces:

org.apache.avalon.excalibur.pool.Poolable, org.apache.avalon.excalibur.pool.Recyclable, org.apache.cocoon.reading.Reader, org.apache.cocoon.sitemap.SitemapModelComponent, org.apache.cocoon.sitemap.SitemapOutputComponent

public class BitstreamReader
extends org.apache.cocoon.reading.AbstractReader
implements org.apache.avalon.excalibur.pool.Recyclable

The BitstreamReader will query DSpace for a particular bitstream and transmit it to the user. There are several method of specifing the bitstream to be develivered. You may refrence a bitstream by either it's id or attempt to resolve the bitstream's name. /bitstream/{handle}/{sequence}/{name} <map:read type="BitstreamReader"> <map:parameter name="handle" value="{1}/{2}"/> <map:parameter name="sequence" value="{3}"/> <map:parameter name="name" value="{4}"/> </map:read> When no handle is assigned yet you can access a bistream using it's internal ID. /bitstream/id/{bitstreamID}/{sequence}/{name} <map:read type="BitstreamReader"> <map:parameter name="bitstreamID" value="{1}"/> <map:parameter name="sequence" value="{2}"/> </map:read> Alternativly, you can access the bitstream via a name instead of directly through it's sequence. /html/{handle}/{name} <map:read type="BitstreamReader"> <map:parameter name="handle" value="{1}/{2}"/> <map:parameter name="name" value="{3}"/> </map:read> Again when no handle is available you can also access it via an internal itemID & name. /html/id/{itemID}/{name} <map:read type="BitstreamReader"> <map:parameter name="itemID" value="{1}"/> <map:parameter name="name" value="{2}"/> </map:read>

Author:

Scott Phillips

Field Summary

protected InputStream	bitstreamInputStream The bitstream file
protected String	bitstreamMimeType The bitstream's mime-type
protected String	bitstreamName The bitstream's name
protected long	bitstreamSize The bitstream's reported size
protected static int	BUFFER_SIZE How big of a buffer should we use when reading from the bitstream before writting to the HTTP response?
protected static int	expires When should a bitstream expire in milliseconds.
protected boolean	isAnonymouslyReadable True if bitstream is readable by anonymous users
protected org.apache.cocoon.environment.Request	request The Cocoon request
protected org.apache.cocoon.environment.Response	response The Cocoon response

Fields inherited from class org.apache.cocoon.reading.AbstractReader

objectModel, out, parameters, resolver, source

Fields inherited from interface org.apache.cocoon.reading.Reader

ROLE

Constructor Summary

BitstreamReader()

Method Summary

void	generate() Write the actual data out to the response.
String	getMimeType() Returns the mime-type of the bitstream.
void	recycle() Recycle
void	setup(org.apache.cocoon.environment.SourceResolver resolver, Map objectModel, String src, org.apache.avalon.framework.parameters.Parameters par) Set up the bitstream reader.

Methods inherited from class org.apache.cocoon.reading.AbstractReader

getLastModified, setOutputStream, shouldSetContentLength

Methods inherited from class org.apache.cocoon.util.AbstractLogEnabled

getLogger, setLogger

Methods inherited from class java.lang.Object

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

Field Detail

BUFFER_SIZE

protected static final int BUFFER_SIZE

How big of a buffer should we use when reading from the bitstream before writting to the HTTP response?

See Also:

Constant Field Values

expires

protected static final int expires

When should a bitstream expire in milliseconds. This should be set to some low value just to prevent someone hiting DSpace repeatily from killing the server. Note: 1000 milliseconds are in a second. Format: minutes * seconds * milliseconds 60 * 60 * 1000 == 1 hour

See Also:

Constant Field Values

response

protected org.apache.cocoon.environment.Response response

The Cocoon response

request

protected org.apache.cocoon.environment.Request request

The Cocoon request

bitstreamInputStream

protected InputStream bitstreamInputStream

The bitstream file

bitstreamSize

protected long bitstreamSize

The bitstream's reported size

bitstreamMimeType

protected String bitstreamMimeType

The bitstream's mime-type

bitstreamName

protected String bitstreamName

The bitstream's name

isAnonymouslyReadable

protected boolean isAnonymouslyReadable

True if bitstream is readable by anonymous users

Constructor Detail

BitstreamReader

public BitstreamReader()

Method Detail

setup

public void setup(org.apache.cocoon.environment.SourceResolver resolver,
                  Map objectModel,
                  String src,
                  org.apache.avalon.framework.parameters.Parameters par)
           throws org.apache.cocoon.ProcessingException,
                  SAXException,
                  IOException

Set up the bitstream reader. See the class description for information on configuration options.

Specified by:

setup in interface org.apache.cocoon.sitemap.SitemapModelComponent

Overrides:

setup in class org.apache.cocoon.reading.AbstractReader

Throws:

org.apache.cocoon.ProcessingException

SAXException

IOException

generate

public void generate()
              throws IOException,
                     SAXException,
                     org.apache.cocoon.ProcessingException

Write the actual data out to the response. Some implementation notes, 1) We set a short expires time just in the hopes of preventing someone from overloading the server by clicking reload a bunch of times. I realize that this is nowhere near 100% effective but it may help in some cases and shouldn't hurt anything. 2) We accept partial downloads, thus if you lose a connection half way through most web browser will enable you to resume downloading the bitstream.

Specified by:

generate in interface org.apache.cocoon.reading.Reader

Throws:

IOException

SAXException

org.apache.cocoon.ProcessingException

getMimeType

public String getMimeType()

Returns the mime-type of the bitstream.

Specified by:

getMimeType in interface org.apache.cocoon.sitemap.SitemapOutputComponent

Overrides:

getMimeType in class org.apache.cocoon.reading.AbstractReader

recycle

public void recycle()

Recycle

Specified by:

recycle in interface org.apache.avalon.excalibur.pool.Recyclable

Overrides:

recycle in class org.apache.cocoon.reading.AbstractReader