org.glassfish.appclient.server.core.jws.servedcontent

Class CachingDynamicContentImpl

java.lang.Object

org.glassfish.appclient.server.core.jws.servedcontent.Content.Adapter

org.glassfish.appclient.server.core.jws.servedcontent.CachingDynamicContentImpl

All Implemented Interfaces:

Content, DynamicContent

public class CachingDynamicContentImpl
extends Content.Adapter
implements DynamicContent

Represents dynamic content in template form.

This class also keeps track of the most recent times the object's template was used to generate content that was different from the result of the previous generation using this template. This information is used in responding to HTTP HEAD requests. Java Web Start uses HEAD requests to find out if a document on the server is more recent than the locally cached copy on the client. If so, then Java Web Start will request the updated version with a routine GET request.

To avoid incorrectly reporting obsolete cached documents as current, this class keeps track of when the content generated by the template is different from the previous generation.

The generated content can depend on request-time information (such as command line arguments passed in the query string of the HTTP request). We save and track only a few individual response instances, because the assumption is that requests that carry query strings (which are converted into command line arguments passed to ACC and on through to the app client) are likely to change frequently and not necessarily be reused often. Keeping a few allows caching the different content resulting from a small number of different argument value settings, but avoids the problems of caching every single response which could become a large memory drain if each request specified a different set of arguments (for instance, one of the arguments could be a timestamp that would change every time).

Nested Class Summary

Nested classes/interfaces inherited from interface org.glassfish.appclient.server.core.jws.servedcontent.DynamicContent

DynamicContent.Instance, DynamicContent.InstanceAdapter

Nested classes/interfaces inherited from interface org.glassfish.appclient.server.core.jws.servedcontent.Content

Content.Adapter, Content.State

Field Summary

Fields

Modifier and Type	Field and Description
protected String	mimeType the MIME type of the data represented by this CachingDynamicContentImpl instance

Constructor Summary

Constructors

Constructor and Description
CachingDynamicContentImpl(String template, String mimeType) Returns a new instance of CachingDynamicContentImpl.
CachingDynamicContentImpl(String template, String mimeType, int maxInstances)

Method Summary

Modifier and Type	Method and Description
protected void	clearInstances() Clears the cached instances.
boolean	equals(Object obj)
DynamicContent.Instance	getExistingInstance(Properties tokenValues) Returns the CachingDynamicContentImpl.InstanceImpl for this template corresponding to the specified substitution token values.
String	getMimeType() Returns the MIME type associated with this content.
DynamicContent.Instance	getOrCreateInstance(Properties tokenValues) Retrieves an existing "instance" of this dynamic content, with placeholders substituted, creating a new one if none already exists.
int	hashCode()
boolean	isMain() Reports whether this dynamic content represents the main JNLP document for an app client.
String	toString() Returns a string representation of the CachingDynamicContentImpl.

Methods inherited from class org.glassfish.appclient.server.core.jws.servedcontent.Content.Adapter

isAvailable, resume, start, state, stop, suspend

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.glassfish.appclient.server.core.jws.servedcontent.Content

isAvailable, resume, start, state, stop, suspend

Field Detail

mimeType

protected final String mimeType

the MIME type of the data represented by this CachingDynamicContentImpl instance

Constructor Detail

CachingDynamicContentImpl

public CachingDynamicContentImpl(String template,
                                 String mimeType)

Returns a new instance of CachingDynamicContentImpl.

Parameters:

origin - the ContentOrigin for the new content instance

contentKey - the content key used to store and retrieve the content

path - the path relative to the subcategory in which this document is addressable

mimeType - the MIME type of data represented by the content generated by this object.

CachingDynamicContentImpl

public CachingDynamicContentImpl(String template,
                                 String mimeType,
                                 int maxInstances)

Method Detail

getExistingInstance

public DynamicContent.Instance getExistingInstance(Properties tokenValues)

Returns the CachingDynamicContentImpl.InstanceImpl for this template corresponding to the specified substitution token values.

Specified by:

getExistingInstance in interface DynamicContent

Parameters:

tokenValues - the name/value pairs to be substituted in the template

createIfAbsent - selects whether a new CachingDynamicContentImpl.InstanceImpl should be created for the resulting text if the content text resulting from the substitution is not already cached by this CachingDynamicContentImpl.

Returns:

the instance corresponding to the content generated by the tokenValues; null if no such instance already exists for this CachingDynamicContentImpl and createIfAbsent was false.

getOrCreateInstance

public DynamicContent.Instance getOrCreateInstance(Properties tokenValues)

Description copied from interface: DynamicContent

Retrieves an existing "instance" of this dynamic content, with placeholders substituted, creating a new one if none already exists.

Specified by:

getOrCreateInstance in interface DynamicContent

Parameters:

tokenValues - maps placeholder tokens to values

Returns:

matching or newly-created Instance

isMain

public boolean isMain()

Description copied from interface: DynamicContent

Reports whether this dynamic content represents the main JNLP document for an app client.

Specified by:

isMain in interface DynamicContent

Returns:

getMimeType

public String getMimeType()

Returns the MIME type associated with this content.

Specified by:

getMimeType in interface DynamicContent

Returns:

the MIME type for this content

clearInstances

protected void clearInstances()

Clears the cached instances.

toString

public String toString()

Returns a string representation of the CachingDynamicContentImpl.

Overrides:

toString in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object