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org.apache.jetspeed.cache.disk
Class JetspeedDiskCacheEntry

java.lang.Object
  org.apache.jetspeed.cache.disk.JetspeedDiskCacheEntry

All Implemented Interfaces:

DiskCacheEntry

public class JetspeedDiskCacheEntry

extends java.lang.Object

implements DiskCacheEntry

A cache entry represents a data source that can be stored locally for efficiency.

It can deliver a string with its contents, but the preferred way to access to the entry contents is through a Reader that will get characters from it.

There are two kinds of entries:

• Local: It is not cached.
• Remote: It can be cached.

Remote entries can be in the following states:

• Invalid: It has no local reference, and the source is transiently or permanently delivering errors
• Stale: It has no local reference, and it is quiet
• Loading: It has no local ref yet, and it is loading
• Refreshing: It has a local ref (current or expired), and it is refreshing it
• Expired: It has a local ref, but its content is no longer valid
• Current: It has a valid local ref

TODO: Some data sources need to be written (i. e., are writable). For those, a mechanism need to be provided to write back the resource. We currently think about HTTP PUT as a mechanism.

Version:

$Id: JetspeedDiskCacheEntry.java,v 1.33 2004/02/23 02:45:29 jford Exp $

Author:

Kevin A. Burton, Santiago Gala

Constructor Summary

protected	JetspeedDiskCacheEntry(java.io.File file) Build a DiskCacheEntry that is based on a cached filesystem entry
	JetspeedDiskCacheEntry(java.lang.String url) Build a DiskCacheEntry that is based on a remote URL and may be (or not) backed on disk.

Method Summary

java.lang.String	getData() Open this URL and read its data, then return it as a string
long	getExpirationTime() Set the expiration date of this entry.
java.io.File	getFile() Get the File that this URL obtains within the cache.
java.io.InputStream	getInputStream() Get an input stream from this entry
long	getLastModified() Return the last modified date of this entry.
java.io.Reader	getReader() Get a Reader from this entry.
java.lang.String	getSourceURL() Reconstruct the original URL based on this URL.
java.lang.String	getURL() Get the URL that was cached.
java.io.Writer	getWriter() Get a Writer to update this entry.
boolean	hasExpired() Test if the entry is expired
void	init() Initialize the file variable, if it is null & the url is not local
boolean	isLocal() Test if the entry is a Local (fake) disk cache entry
void	setExpirationTime(long time) Set the expiration date of this entry.
void	setFile(java.io.File file) Set the file.
void	setLastModified(long time) Set the last modified date of this entry.
void	setURL(java.lang.String url) Set the url on which this is based.

Methods inherited from class java.lang.Object

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

Constructor Detail

JetspeedDiskCacheEntry

protected JetspeedDiskCacheEntry(java.io.File file)

Build a DiskCacheEntry that is based on a cached filesystem entry

This is used to reconstruct the entries from the cache at boot time

JetspeedDiskCacheEntry

public JetspeedDiskCacheEntry(java.lang.String url)

Build a DiskCacheEntry that is based on a remote URL and may be (or not) backed on disk.

Method Detail

init

public void init()

Initialize the file variable, if it is null & the url is not local

getURL

public java.lang.String getURL()

Description copied from interface: DiskCacheEntry

Get the URL that was cached.

Specified by:

getURL in interface DiskCacheEntry

getSourceURL

public java.lang.String getSourceURL()

Reconstruct the original URL based on this URL.

Specified by:

getSourceURL in interface DiskCacheEntry

getFile

public java.io.File getFile()

Get the File that this URL obtains within the cache.

Specified by:

getFile in interface DiskCacheEntry

setFile

public void setFile(java.io.File file)

Set the file.

getData

public java.lang.String getData()
                         throws java.io.IOException

Open this URL and read its data, then return it as a string

Specified by:

getData in interface DiskCacheEntry

Throws:

java.io.IOException

getInputStream

public java.io.InputStream getInputStream()
                                   throws java.io.IOException

Get an input stream from this entry

Specified by:

getInputStream in interface DiskCacheEntry

Throws:

java.io.IOException

getReader

public java.io.Reader getReader()
                         throws java.io.IOException

Get a Reader from this entry. ( Patch for handling character encoding sent by Yoshihiro KANNA ) For local entries, we assume that the URL coming from the WEB server is allright WRT encoding For remote entries, we assume that the cache saved them in the local store using UTF8 encoding

Specified by:

getReader in interface DiskCacheEntry

Throws:

java.io.IOException

getWriter

public java.io.Writer getWriter()
                         throws java.io.IOException

Get a Writer to update this entry. For local entries, we assume that the URL coming from the WEB server allows PUT For remote entries, we throws a IOException

Specified by:

getWriter in interface DiskCacheEntry

Throws:

java.io.IOException

getLastModified

public long getLastModified()

Return the last modified date of this entry.

Specified by:

getLastModified in interface DiskCacheEntry

setLastModified

public void setLastModified(long time)

Set the last modified date of this entry.

Specified by:

setLastModified in interface DiskCacheEntry

setURL

public void setURL(java.lang.String url)

Set the url on which this is based.

getExpirationTime

public long getExpirationTime()

Set the expiration date of this entry.

Specified by:

getExpirationTime in interface DiskCacheEntry

setExpirationTime

public void setExpirationTime(long time)

Set the expiration date of this entry.

Specified by:

setExpirationTime in interface DiskCacheEntry

hasExpired

public boolean hasExpired()

Description copied from interface: DiskCacheEntry

Test if the entry is expired

Specified by:

hasExpired in interface DiskCacheEntry

isLocal

public boolean isLocal()

Description copied from interface: DiskCacheEntry

Test if the entry is a Local (fake) disk cache entry

Specified by:

isLocal in interface DiskCacheEntry