net.sf.jasperreports.engine.fill

Class JRAbstractLRUVirtualizer

java.lang.Object

net.sf.jasperreports.engine.fill.JRAbstractLRUVirtualizer

All Implemented Interfaces:

JRVirtualizer

Direct Known Subclasses:

JRFileVirtualizer, JRGzipVirtualizer, StoreFactoryVirtualizer, StoreVirtualizer

public abstract class JRAbstractLRUVirtualizer
extends Object
implements JRVirtualizer

Abstract base for LRU and serialization based virtualizer

Author:

John Bindel

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	JRAbstractLRUVirtualizer.Cache This class keeps track of how many objects are currently in memory, and when there are too many, it pushes the last touched one to disk.
protected static class	JRAbstractLRUVirtualizer.CacheReference

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.commons.collections.map.ReferenceMap	lastObjectMap
protected WeakReference<JRVirtualizable>	lastObjectRef
protected org.apache.commons.collections.map.ReferenceMap	lastObjectSet
protected VirtualizationSerializer	serializer

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JRAbstractLRUVirtualizer(int maxSize)

Method Summary

Methods

Modifier and Type	Method and Description
void	clearData(JRVirtualizable o) Called when the virtual object paged-out data should be freed.
void	deregisterObject(JRVirtualizable o) Lets this virtualizer know that it no longer must track the object.
protected void	dispose(JRVirtualizable o)
protected abstract void	dispose(String virtualId) Removes the external data associated with a virtualizable object.
protected void	disposeAll()
protected void	evict()
protected void	finalize()
protected boolean	isEvictable(JRVirtualizable value)
protected boolean	isPagedOut(String id)
protected boolean	isPagedOutAndTouch(JRVirtualizable o, String uid)
boolean	isReadOnly() Determines whether the virtualizer is in read-only mode.
protected boolean	isReadOnly(JRVirtualizable o)
protected JRVirtualizable	lastObject()
protected abstract void	pageIn(JRVirtualizable o) Reads a virtualizable object's data from an external storage.
protected abstract void	pageOut(JRVirtualizable o) Writes a virtualizable object's data to an external storage.
protected void	readData(JRVirtualizable o, InputStream in) Reads serialized identity and virtual data for a virtualizable object from a stream.
void	registerObject(JRVirtualizable o) Lets this virtualizer know that it must track the object.
void	requestData(JRVirtualizable o) Called when the virtual object must be paged-in.
protected void	reset()
protected void	setLastObject(JRVirtualizable o)
void	setReadOnly(boolean ro) Sets the read only mode for the virtualizer.
void	touch(JRVirtualizable o) Lets the virtualizer know that this object is still being used.
void	virtualizeData(JRVirtualizable o) Called when the virtual object should be paged-out.
protected void	writeData(JRVirtualizable o, OutputStream out) Writes serialized indentity and virtual data of a virtualizable object to a stream.

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.jasperreports.engine.JRVirtualizer

cleanup

Field Detail

serializer

protected final VirtualizationSerializer serializer

lastObjectRef

protected volatile WeakReference<JRVirtualizable> lastObjectRef

lastObjectMap

protected org.apache.commons.collections.map.ReferenceMap lastObjectMap

lastObjectSet

protected org.apache.commons.collections.map.ReferenceMap lastObjectSet

Constructor Detail

JRAbstractLRUVirtualizer

protected JRAbstractLRUVirtualizer(int maxSize)

Parameters:

maxSize - the maximum size (in JRVirtualizable objects) of the paged in cache.

Method Detail

isPagedOut

protected final boolean isPagedOut(String id)

isPagedOutAndTouch

protected boolean isPagedOutAndTouch(JRVirtualizable o,
                         String uid)

lastObject

protected JRVirtualizable lastObject()

setLastObject

protected final void setLastObject(JRVirtualizable o)

setReadOnly

public void setReadOnly(boolean ro)

Sets the read only mode for the virtualizer.

When in read-only mode, the virtualizer assumes that virtualizable objects are final and any change in a virtualizable object's data is discarded.

When the virtualizer is used for multiple virtualization contexts (in shared mode), calling this method would override the read-only flags from all the contexts and all the objects will be manipulated in read-only mode. Use JRVirtualizationContext.setReadOnly(boolean) to set the read-only mode for one specific context.

Parameters:

ro - the read-only mode to set

isReadOnly

public boolean isReadOnly()

Determines whether the virtualizer is in read-only mode.

Returns:

whether the virtualizer is in read-only mode

See Also:

setReadOnly(boolean)

isReadOnly

protected final boolean isReadOnly(JRVirtualizable o)

registerObject

public void registerObject(JRVirtualizable o)

Description copied from interface: JRVirtualizer

Lets this virtualizer know that it must track the object.

All virtualizable object must register with their virtualizer upon construction.

Specified by:

registerObject in interface JRVirtualizer

isEvictable

protected boolean isEvictable(JRVirtualizable value)

evict

protected void evict()

deregisterObject

public void deregisterObject(JRVirtualizable o)

Description copied from interface: JRVirtualizer

Lets this virtualizer know that it no longer must track the object.

Specified by:

deregisterObject in interface JRVirtualizer

touch

public void touch(JRVirtualizable o)

Description copied from interface: JRVirtualizer

Lets the virtualizer know that this object is still being used. This should be called to help the virtualizer determine which objects to keep in its cache, and which objects to page-out when it must do some paging-out.

The virtualizer gets to decide what type of caching strategy it will use.

Specified by:

touch in interface JRVirtualizer

requestData

public void requestData(JRVirtualizable o)

Description copied from interface: JRVirtualizer

Called when the virtual object must be paged-in.

If the object's virtual data is not paged-out, the object will only be touched.

Specified by:

requestData in interface JRVirtualizer

clearData

public void clearData(JRVirtualizable o)

Description copied from interface: JRVirtualizer

Called when the virtual object paged-out data should be freed.

If the object's virtual data is not paged-out, the object will only be touched.

Specified by:

clearData in interface JRVirtualizer

virtualizeData

public void virtualizeData(JRVirtualizable o)

Description copied from interface: JRVirtualizer

Called when the virtual object should be paged-out.

Specified by:

virtualizeData in interface JRVirtualizer

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

writeData

protected final void writeData(JRVirtualizable o,
             OutputStream out)
                        throws JRRuntimeException

Writes serialized indentity and virtual data of a virtualizable object to a stream.

Parameters:

o - the serialized object

out - the output stream

Throws:

JRRuntimeException

readData

protected final void readData(JRVirtualizable o,
            InputStream in)
                       throws JRRuntimeException

Reads serialized identity and virtual data for a virtualizable object from a stream.

Parameters:

o - the virtualizable object

in - the input stream

Throws:

JRRuntimeException

reset

protected void reset()

disposeAll

protected final void disposeAll()

pageOut

protected abstract void pageOut(JRVirtualizable o)
                         throws IOException

Writes a virtualizable object's data to an external storage.

Parameters:

o - a virtualizable object

Throws:

IOException

pageIn

protected abstract void pageIn(JRVirtualizable o)
                        throws IOException

Reads a virtualizable object's data from an external storage.

Parameters:

o - a virtualizable object

Throws:

IOException

dispose

protected void dispose(JRVirtualizable o)

dispose

protected abstract void dispose(String virtualId)

Removes the external data associated with a virtualizable object.

Parameters:

virtualId - the ID of the virtualizable object