org.apache.xmlgraphics.ps.dsc
Class ResourceTracker

java.lang.Object
  org.apache.xmlgraphics.ps.dsc.ResourceTracker

public class ResourceTracker
extends Object

This class is used to track resources in a DSC-compliant PostScript file. The distinction is made between supplied and needed resources. For the details of this distinction, please see the DSC specification.

Constructor Summary

ResourceTracker()

Method Summary

void	declareInlined(PSResource res) This method declares that the given resource will be inlined and can therefore be removed from resource tracking.
Set	getDocumentNeededResources() Returns the set of needed resources.
Set	getDocumentSuppliedResources() Returns the set of supplied resources.
long	getUsageCount(PSResource res) Returns the number of times a resource has been used inside the current DSC document.
boolean	isResourceSupplied(PSResource res) Indicates whether a particular resource is supplied, rather than needed.
void	notifyResourceUsageOnPage(Collection resources) Notifies the resource tracker about the usage of resources on the current page.
void	notifyResourceUsageOnPage(PSResource res) Notifies the resource tracker about the usage of a resource on the current page.
void	notifyStartNewPage() Notifies the resource tracker that a new page has been started and that the page resource set can be cleared.
void	registerNeededResource(PSResource res) Registers a needed resource.
void	registerSuppliedResource(PSResource res) Registers a supplied resource.
void	writeDocumentResources(PSGenerator gen) Writes a DSC comment for the needed and supplied resourced for the current DSC document.
void	writePageResources(PSGenerator gen) Writes a DSC comment for the accumulated used resources on the current page.
void	writeResources(boolean pageLevel, PSGenerator gen) Writes a DSC comment for the accumulated used resources, either at page level or at document level.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResourceTracker

public ResourceTracker()

Method Detail

getDocumentSuppliedResources

public Set getDocumentSuppliedResources()

Returns the set of supplied resources.

Returns:

the set of supplied resources

getDocumentNeededResources

public Set getDocumentNeededResources()

Returns the set of needed resources.

Returns:

the set of needed resources

notifyStartNewPage

public void notifyStartNewPage()

Notifies the resource tracker that a new page has been started and that the page resource set can be cleared.

registerSuppliedResource

public void registerSuppliedResource(PSResource res)

Registers a supplied resource. If the same resources is already in the set of needed resources, it is removed there.

Parameters:

res - the resource

registerNeededResource

public void registerNeededResource(PSResource res)

Registers a needed resource. If the same resources is already in the set of supplied resources, it is ignored, i.e. it is assumed to be supplied.

Parameters:

res - the resource

notifyResourceUsageOnPage

public void notifyResourceUsageOnPage(PSResource res)

Notifies the resource tracker about the usage of a resource on the current page.

Parameters:

res - the resource being used

notifyResourceUsageOnPage

public void notifyResourceUsageOnPage(Collection resources)

Notifies the resource tracker about the usage of resources on the current page.

Parameters:

resources - the resources being used

isResourceSupplied

public boolean isResourceSupplied(PSResource res)

Indicates whether a particular resource is supplied, rather than needed.

Parameters:

res - the resource

Returns:

true if the resource is registered as being supplied.

writeResources

public void writeResources(boolean pageLevel,
                           PSGenerator gen)
                    throws IOException

Writes a DSC comment for the accumulated used resources, either at page level or at document level.

Parameters:

pageLevel - true if the DSC comment for the page level should be generated, false for the document level (in the trailer)

gen - the PSGenerator to write the DSC comments with

Throws:

IOException - In case of an I/O problem

writePageResources

public void writePageResources(PSGenerator gen)
                        throws IOException

Writes a DSC comment for the accumulated used resources on the current page. Then it commits all those resources to the used resources on document level.

Parameters:

gen - the PSGenerator to write the DSC comments with

Throws:

IOException - In case of an I/O problem

writeDocumentResources

public void writeDocumentResources(PSGenerator gen)
                            throws IOException

Writes a DSC comment for the needed and supplied resourced for the current DSC document.

Parameters:

gen - the PSGenerator to write the DSC comments with

Throws:

IOException - In case of an I/O problem

declareInlined

public void declareInlined(PSResource res)

This method declares that the given resource will be inlined and can therefore be removed from resource tracking. This is useful when you don't know beforehand if a resource will be used multiple times. If it's only used once it's better to inline the resource to lower the maximum memory needed inside the PostScript interpreter.

Parameters:

res - the resource

getUsageCount

public long getUsageCount(PSResource res)

Returns the number of times a resource has been used inside the current DSC document.

Parameters:

res - the resource

Returns:

the number of times the resource has been used