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 methods of specifing the bitstream to be delivered. You may reference 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 bitstream 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> Alternatively, 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> Added request-item support. Original Concept, JSPUI version: Universidade do Minho at www.uminho.pt Sponsorship of XMLUI version: Instituto Oceanográfico de España at www.ieo.es

Author:

Scott Phillips, Adán Román Ruiz at arvo.es (added request item support)

Field Summary

Fields

Modifier and Type	Field and Description
protected java.io.InputStream	bitstreamInputStream The bitstream file
protected java.lang.String	bitstreamMimeType The bitstream's mime-type
protected java.lang.String	bitstreamName The bitstream's name
protected long	bitstreamSize The bitstream's reported size
protected static int	BUFFER_SIZE How big a buffer should we use when reading from the bitstream before writing 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

Constructors

Constructor and Description
BitstreamReader()

Method Summary

Methods

Modifier and Type	Method and Description
void	generate() Write the actual data out to the response.
java.lang.String	getMimeType() Returns the mime-type of the bitstream.
void	recycle() Recycle
void	setup(org.apache.cocoon.environment.SourceResolver resolver, java.util.Map objectModel, java.lang.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 a buffer should we use when reading from the bitstream before writing 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 repeatedy from killing the server. Note: there are 1000 milliseconds 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 java.io.InputStream bitstreamInputStream

The bitstream file

bitstreamSize

protected long bitstreamSize

The bitstream's reported size

bitstreamMimeType

protected java.lang.String bitstreamMimeType

The bitstream's mime-type

bitstreamName

protected java.lang.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,
         java.util.Map objectModel,
         java.lang.String src,
         org.apache.avalon.framework.parameters.Parameters par)
           throws org.apache.cocoon.ProcessingException,
                  org.xml.sax.SAXException,
                  java.io.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

org.xml.sax.SAXException

java.io.IOException

generate

public void generate()
              throws java.io.IOException,
                     org.xml.sax.SAXException,
                     org.apache.cocoon.ProcessingException

Write the actual data out to the response. Some implementation notes: 1) We set a short expiration 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 halfway through most web browser will enable you to resume downloading the bitstream.

Specified by:

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

Throws:

java.io.IOException

org.xml.sax.SAXException

org.apache.cocoon.ProcessingException

getMimeType

public java.lang.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