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edu.utah.janosvm.kit.comm.commspace
Class CommSpaceHandle
java.lang.Object | +--edu.utah.janosvm.sys.ListNode | +--edu.utah.janosvm.sys.Importable | +--edu.utah.janosvm.kit.comm.commspace.CommSpaceHandle
- public final class CommSpaceHandle
- extends Importable
A handle on a CommSpace. A CommSpace is an inter-process communication facility based lightly on Linda's "tuples". The space consists of an array of CommSpaceElements. Elements are copied out on read. A thread may write, read, swap, "wait" or "take" any element.
XXX Semantics during a failed take() are probably wrong.
- Author:
- Janos Ministry of Development
- See Also:
CommSpace
| Fields inherited from class edu.utah.janosvm.sys.ListNode |
pred,
succ |
| Constructor Summary | |
CommSpaceHandle()
Create an empty handle. |
|
CommSpaceHandle(CommSpaceHandle other)
Copy constructor. |
|
| Method Summary | |
protected void |
bindTo(Exportable ex)
Bind this Importable to the given Exportable. |
static CommSpaceHandle |
newCommSpace(CommSpaceHandle csh,
int size)
Create a CommSpace and attach it to the given handle. |
static CommSpaceHandle |
newCommSpace(int size)
Create a new CommSpace of the given size and return a handle to it. |
CommSpaceElement |
read(int index)
Read the element at the given index. |
int |
resize(int newsize)
Resize the CommSpace pointed to by this handle to contain the given number of slots. |
int |
size()
Return the number of slots in the CommSpace pointed to by this handle. |
CommSpaceElement |
swap(int index,
CommSpaceElement elem)
Swap an element with the one currently in the given index. |
CommSpaceElement |
take(int index)
Take an element from the given index and put a null in its place. |
protected void |
unbindFrom()
Unbind this Importable from any objects its referencing. |
CommSpaceElement |
waitToTake(int index)
Wait for an element to be placed into the given index. |
void |
write(int index,
CommSpaceElement elem)
Write the given element to the given index. |
| Methods inherited from class edu.utah.janosvm.sys.Importable |
copy,
finalize,
revoke,
toString |
| Methods inherited from class edu.utah.janosvm.sys.ListNode |
append,
clone,
prepend,
remove |
| Methods inherited from class java.lang.Object |
equals,
getClass,
hashCode,
notify,
notifyAll,
wait,
wait,
wait |
| Constructor Detail |
CommSpaceHandle
public CommSpaceHandle()
- Create an empty handle.
- See Also:
newCommSpace(CommSpaceHandle,int)
CommSpaceHandle
public CommSpaceHandle(CommSpaceHandle other)
- Copy constructor. Only used when passing a
csh to a child flow.
- Parameters:
other- The handle to copy.
| Method Detail |
newCommSpace
public static CommSpaceHandle newCommSpace(int size)
- Create a new CommSpace of the given size and return a handle to
it.
- Parameters:
size- The size of the CommSpace.- Returns:
- The handle to the CommSpace.
newCommSpace
public static CommSpaceHandle newCommSpace(CommSpaceHandle csh, int size)
- Create a CommSpace and attach it to the given handle.
- Parameters:
csh- The CommSpaceHandle to attach to the newly created CommSpace.size- The size of the CommSpace.- Returns:
- The handle that was passed in.
bindTo
protected void bindTo(Exportable ex)
- Description copied from class: Importable
- Bind this Importable to the given Exportable. The most common
implementation of this method would be to cast the Exportable to the
type that the Importable subclass handles and store it in the object as
well as any other handy pointers/values.
- Overrides:
- bindTo in class Importable
- Tags copied from class: Importable
- Parameters:
ex- The Exportable that is being imported.
unbindFrom
protected void unbindFrom()
- Description copied from class: Importable
- Unbind this Importable from any objects its referencing. The most
common implementation of this method would be null out any object
references in this object.
- Overrides:
- unbindFrom in class Importable
size
public int size()
- Return the number of slots in the CommSpace pointed to by this handle.
resize
public int resize(int newsize)
- Resize the CommSpace pointed to by this handle to contain
the given number of slots.
XXX what happens when resizing to smaller than current and dropping items?
write
public void write(int index,
CommSpaceElement elem)
throws java.lang.ArrayIndexOutOfBoundsException
- Write the given element to the given index. Overwrites
whatever is already there.
- Parameters:
index- The index in the CommSpace to write into.elem- The element to copy into the CommSpace.
take
public CommSpaceElement take(int index) throws java.lang.ArrayIndexOutOfBoundsException
- Take an element from the given index and put a null in its place.
The read and replace are atomic with respect to other take()s at the
given index. XXX semantically equivalent to
swap(index, null)
- Parameters:
index- The index in the CommSpace that we should take.- Returns:
- null or the CommSpaceElement that was in the given index.
- See Also:
swap(int,CommSpaceElement)
waitToTake
public CommSpaceElement waitToTake(int index) throws java.lang.InterruptedException, java.lang.ArrayIndexOutOfBoundsException
- Wait for an element to be placed into the given index. Then
atomically take the element and replace with null.
- Parameters:
index- The index in the CommSpace that we should take.- Returns:
- the CommSpaceElement that was in the given index.
read
public CommSpaceElement read(int index) throws java.lang.ArrayIndexOutOfBoundsException
- Read the element at the given index.
- Parameters:
index- The index in the CommSpace that we should take.- Returns:
- Null or the CommSpaceElement that was in the given index.
swap
public CommSpaceElement swap(int index, CommSpaceElement elem) throws java.lang.ArrayIndexOutOfBoundsException
- Swap an element with the one currently in the given index.
- Parameters:
index- The index in the CommSpace that we should take.elem- The element to swap into the index.- Returns:
- Null or the CommSpaceElement that was in the given index.
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This documentation is Copyright (C) 2000-2002 The University of Utah. All Rights Reserved. See the documentation license for distribution terms and restrictions.
Documentation, software, and mailing lists for the JanosVM can be found at the Janos Project web page: http://www.cs.utah.edu/flux/janos/
Generated on Mar 17, 2002