OpenJDK 27 · sun.java2d.pipe.RenderQueue · APIdia, the JavaDoc alternative

The RenderQueue class encapsulates a RenderBuffer on which rendering operations are enqueued. Note that the RenderQueue lock must be acquired before performing any operations on the queue (e.g. enqueuing an operation or flushing the queue). A sample usage scenario follows: public void drawSomething(...) { rq.lock(); try { ctx.validate(...); rq.ensureCapacity(4); rq.getBuffer().putInt(DRAW_SOMETHING); ... } finally { rq.unlock(); } } If you are enqueuing an operation that involves 8-byte parameters (i.e. long or double values), it is imperative that you ensure proper alignment of the underlying RenderBuffer. This can be accomplished simply by providing an offset to the first 8-byte parameter in your operation to the ensureCapacityAndAlignment() method. For example: public void drawStuff(...) { rq.lock(); try { RenderBuffer buf = rq.getBuffer(); ctx.validate(...); // 28 total bytes in the operation, 12 bytes to the first long rq.ensureCapacityAndAlignment(28, 12); buf.putInt(DRAW_STUFF); buf.putInt(x).putInt(y); buf.putLong(addr1); buf.putLong(addr2); } finally { rq.unlock(); } }

Modifier and Type	Field and Description
protected RenderBuffer	buf The underlying buffer for this queue.
private static final int	BUFFER_SIZE The size of the underlying buffer, in bytes.
protected Set<Object>	refSet A Set containing hard references to Objects that must stay alive until the queue has been completely flushed.

Access	Constructor and Description
protected	RenderQueue()

Method Summary

Modifier and Type	Method and Description
public final void	addReference(Object ref) Adds the given Object to the set of hard references, which will prevent that Object from being disposed until the queue has been flushed completely.
public final void	ensureAlignment(int offset (in bytes) from the current position to the first 8-byte value used in the following operation first8ByteValueOffset) Inserts a 4-byte NOOP token when necessary to ensure that all 8-byte parameters for the following operation are added to the underlying buffer with an 8-byte memory alignment.
public final void	ensureCapacity(int size (in bytes) of the following operation opsize) Ensures that there will be enough room on the underlying buffer for the following operation.
public final void	ensureCapacityAndAlignment(int size (in bytes) of the following operation opsize, int offset (in bytes) from the current position to the first 8-byte value used in the following operation first8ByteValueOffset) Convenience method that is equivalent to calling ensureCapacity() followed by ensureAlignment().
public abstract void	flushAndInvokeNow(Runnable task) Immediately processes each operation currently pending on the buffer, and then invokes the provided task.
public abstract void	flushNow() Immediately processes each operation currently pending on the buffer.
public void	flushNow(int position) Updates the current position of the underlying buffer, and then flushes the queue immediately.
public final RenderBuffer	getBuffer() Returns the encapsulated RenderBuffer object.
public final void	lock() Locks the queue for read/write access.
public final boolean	tryLock() Attempts to lock the queue.
public final void	unlock() Unlocks the queue.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

buf	back to summary
protected RenderBuffer buf The underlying buffer for this queue.

BUFFER_SIZE	back to summary
private static final int BUFFER_SIZE The size of the underlying buffer, in bytes.

refSet	back to summary
protected Set<Object> refSet A Set containing hard references to Objects that must stay alive until the queue has been completely flushed.

Constructor Detail

RenderQueue	back to summary
protected RenderQueue()

Method Detail

addReference	back to summary
public final void addReference(Object ref) Adds the given Object to the set of hard references, which will prevent that Object from being disposed until the queue has been flushed completely. This is useful in cases where some enqueued data could become invalid if the reference Object were garbage collected before the queue could be processed. (For example, keeping a hard reference to a FontStrike will prevent any enqueued glyph images associated with that strike from becoming invalid before the queue is flushed.) The reference set will be cleared immediately after the queue is flushed each time.

addReference

back to summary

public final void addReference(Object ref)

Adds the given Object to the set of hard references, which will prevent that Object from being disposed until the queue has been flushed completely. This is useful in cases where some enqueued data could become invalid if the reference Object were garbage collected before the queue could be processed. (For example, keeping a hard reference to a FontStrike will prevent any enqueued glyph images associated with that strike from becoming invalid before the queue is flushed.) The reference set will be cleared immediately after the queue is flushed each time.

ensureAlignment	back to summary
public final void ensureAlignment(int first8ByteValueOffset) Inserts a 4-byte NOOP token when necessary to ensure that all 8-byte parameters for the following operation are added to the underlying buffer with an 8-byte memory alignment. Parameters first8ByteValueOffset:int offset (in bytes) from the current position to the first 8-byte value used in the following operation

ensureAlignment

back to summary

public final void ensureAlignment(int first8ByteValueOffset)

Inserts a 4-byte NOOP token when necessary to ensure that all 8-byte parameters for the following operation are added to the underlying buffer with an 8-byte memory alignment.

Parameters

first8ByteValueOffset:int: offset (in bytes) from the current position to the first 8-byte value used in the following operation

ensureCapacity	back to summary
public final void ensureCapacity(int opsize) Ensures that there will be enough room on the underlying buffer for the following operation. If the operation will not fit given the remaining space, the buffer will be flushed immediately, leaving an empty buffer for the impending operation. Parameters opsize:int size (in bytes) of the following operation

ensureCapacity

back to summary

public final void ensureCapacity(int opsize)

Ensures that there will be enough room on the underlying buffer for the following operation. If the operation will not fit given the remaining space, the buffer will be flushed immediately, leaving an empty buffer for the impending operation.

Parameters

opsize:int: size (in bytes) of the following operation

ensureCapacityAndAlignment	back to summary
public final void ensureCapacityAndAlignment(int opsize, int first8ByteValueOffset) Convenience method that is equivalent to calling ensureCapacity() followed by ensureAlignment(). The ensureCapacity() call allows for an extra 4 bytes of space in case the ensureAlignment() method needs to insert a NOOP token on the buffer. Parameters opsize:int size (in bytes) of the following operation first8ByteValueOffset:int offset (in bytes) from the current position to the first 8-byte value used in the following operation

ensureCapacityAndAlignment

back to summary

public final void ensureCapacityAndAlignment(int opsize, int first8ByteValueOffset)

Convenience method that is equivalent to calling ensureCapacity() followed by ensureAlignment(). The ensureCapacity() call allows for an extra 4 bytes of space in case the ensureAlignment() method needs to insert a NOOP token on the buffer.

Parameters

opsize:int: size (in bytes) of the following operation
first8ByteValueOffset:int: offset (in bytes) from the current position to the first 8-byte value used in the following operation

flushAndInvokeNow	back to summary
public abstract void flushAndInvokeNow(Runnable task) Immediately processes each operation currently pending on the buffer, and then invokes the provided task. This method will block until the entire buffer has been flushed and the provided task has been executed. The queue lock must be acquired before calling this method.

flushNow	back to summary
public abstract void flushNow() Immediately processes each operation currently pending on the buffer. This method will block until the entire buffer has been flushed. The queue lock must be acquired before calling this method.

flushNow	back to summary
public void flushNow(int position) Updates the current position of the underlying buffer, and then flushes the queue immediately. This method is useful when native code has added data to the queue and needs to flush immediately.

getBuffer	back to summary
public final RenderBuffer getBuffer() Returns the encapsulated RenderBuffer object.

lock	back to summary
public final void lock() Locks the queue for read/write access.

tryLock	back to summary
public final boolean tryLock() Attempts to lock the queue. If successful, this method returns true, indicating that the caller is responsible for calling `unlock`; otherwise this method returns false.

unlock	back to summary
public final void unlock() Unlocks the queue.

public abstract Class RenderQueue

Field Summary

Constructor Summary

Method Summary

Field Detail

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Method Detail