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org.apache.cocoon.components.flow
Class WebContinuation

java.lang.Object
  org.apache.cocoon.components.flow.WebContinuation

All Implemented Interfaces:

Cloneable, Comparable

Direct Known Subclasses:

ContinuationsManagerImpl.HolderAwareWebContinuation

public class WebContinuation
extends Object
implements Comparable, Cloneable

Representation of continuations in a Web environment.

Because a user may click on the back button of the browser and restart a saved computation in a continuation, each WebContinuation becomes the parent of a subtree of continuations.

If there is no parent WebContinuation, the created continuation becomes the root of a tree of WebContinuations.

Since:

March 19, 2002

Version:

CVS $Id: WebContinuation.html 1304258 2012-03-23 10:09:27Z ilgrosso $

Author:

Ovidiu Predescu

Field Summary

protected List	children The children continuations.
protected Object	continuation The continuation this object represents.
protected ContinuationsDisposer	disposer Holds the ContinuationsDisposer to call when this continuation gets invalidated.
protected String	id The continuation id used to represent this instance in Web pages.
protected String	interpreterId Interpreter id that this continuation is bound to
protected long	lastAccessTime When was this continuation accessed last time.
protected WebContinuation	parentContinuation The parent WebContinuation from which processing last started.
protected int	timeToLive Indicates how long does this continuation will live (in seconds).
protected Object	userObject A user definable object.

Method Summary

Object	clone() Creates a clone of this WebContinuation without trying to clone the actual continuation, the user object or the disposer.
int	compareTo(Object other) Compares the expiration time of this instance with that of the WebContinuation passed as argument.
void	detachFromParent()
protected String	display(int depth) Debugging method.
void	dispose() Dispose this continuation.
boolean	disposed() Return true if this continuation was disposed of
boolean	equals(Object another) True if the identifiers are the same, false otherwise.
Object	getAttribute(String name) Get an attribute of this continuation
Enumeration	getAttributeNames() Enumerate the attributes of this continuation.
List	getChildren() Return the children WebContinuation which were created as a result of resuming the processing from the current continuation.
Object	getContinuation() Return the continuation object.
WebContinuation	getContinuation(int level) Return the ancestor continuation situated levels above the current continuation.
String	getId() Returns the string identifier of this WebContinuation.
String	getInterpreterId() Returns the string identifier of the interpreter to which this WebContinuation is bound.
long	getLastAccessTime() Returns the last time this WebContinuation was accessed.
WebContinuation	getParentContinuation() Return the parent WebContinuation.
long	getTimeToLive() Returns the the timetolive for this WebContinuation.
Object	getUserObject() Obtains the user object associated with this instance.
boolean	hasExpired() Determines whether this continuation has expired
int	hashCode() Returns the hash code of the associated identifier.
boolean	interpreterMatches(String interpreterId)
void	removeAttribute(String name) Remove an attribute of this continuation
void	setAttribute(String name, Object value) Set an attribute of this continuation
void	setUserObject(Object obj) Sets the user object associated with this instance.
String	toString() Debugging method.
protected void	updateLastAccessTime() Update the continuation in the

Methods inherited from class java.lang.Object

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

Field Detail

continuation

protected Object continuation

The continuation this object represents.

parentContinuation

protected WebContinuation parentContinuation

The parent WebContinuation from which processing last started. If null, there is no parent continuation associated, and this is the first one to be created in a processing. In this case this WebContinuation instance becomes the root of the tree maintained by the ContinuationsManager.

See Also:

ContinuationsManager

children

protected List children

The children continuations. These are continuations created by resuming the processing from the point stored by continuation.

id

protected String id

The continuation id used to represent this instance in Web pages.

interpreterId

protected String interpreterId

Interpreter id that this continuation is bound to

userObject

protected Object userObject

A user definable object. This is present for convenience, to store any information associated with this WebContinuation a particular implementation might need.

lastAccessTime

protected long lastAccessTime

When was this continuation accessed last time. Each time the continuation is accessed, this time is set to the time of the access.

timeToLive

protected int timeToLive

Indicates how long does this continuation will live (in seconds). The continuation will be removed once the current time is bigger than lastAccessTime + timeToLive.

disposer

protected ContinuationsDisposer disposer

Holds the ContinuationsDisposer to call when this continuation gets invalidated.

Method Detail

getAttribute

public Object getAttribute(String name)

Get an attribute of this continuation

Parameters:

name - the attribute name.

setAttribute

public void setAttribute(String name,
                         Object value)

Set an attribute of this continuation

Parameters:

name - the attribute name

value - its value

removeAttribute

public void removeAttribute(String name)

Remove an attribute of this continuation

Parameters:

name - the attribute name

getAttributeNames

public Enumeration getAttributeNames()

Enumerate the attributes of this continuation.

Returns:

an enumeration of strings

getContinuation

public Object getContinuation()

Return the continuation object.

Returns:

an Object value

getContinuation

public WebContinuation getContinuation(int level)

Return the ancestor continuation situated levels above the current continuation. The current instance is considered to be at level 0. The parent continuation of the receiving instance at level 1, its parent is at level 2 relative to the receiving instance. If level is bigger than the depth of the tree, the root of the tree is returned.

Parameters:

level - an int value

Returns:

a WebContinuation value

getParentContinuation

public WebContinuation getParentContinuation()

Return the parent WebContinuation. Equivalent with getContinuation(1).

Returns:

a WebContinuation value

getChildren

public List getChildren()

Return the children WebContinuation which were created as a result of resuming the processing from the current continuation.

Returns:

a List value

getId

public String getId()

Returns the string identifier of this WebContinuation.

Returns:

a String value

getInterpreterId

public String getInterpreterId()

Returns the string identifier of the interpreter to which this WebContinuation is bound.

Returns:

a String value

getLastAccessTime

public long getLastAccessTime()

Returns the last time this WebContinuation was accessed.

Returns:

a long value

getTimeToLive

public long getTimeToLive()

Returns the the timetolive for this WebContinuation.

Returns:

a long value

setUserObject

public void setUserObject(Object obj)

Sets the user object associated with this instance.

Parameters:

obj - an Object value

getUserObject

public Object getUserObject()

Obtains the user object associated with this instance.

Returns:

an Object value

hashCode

public int hashCode()

Returns the hash code of the associated identifier.

Overrides:

hashCode in class Object

Returns:

an int value

equals

public boolean equals(Object another)

True if the identifiers are the same, false otherwise.

Overrides:

equals in class Object

Parameters:

another - an Object value

Returns:

a boolean value

compareTo

public int compareTo(Object other)

Compares the expiration time of this instance with that of the WebContinuation passed as argument.

Note: this class has a natural ordering that is inconsistent with equals.

.

Specified by:

compareTo in interface Comparable

Parameters:

other - an Object value, which should be a WebContinuation instance

Returns:

an int value

updateLastAccessTime

protected void updateLastAccessTime()

Update the continuation in the

hasExpired

public boolean hasExpired()

Determines whether this continuation has expired

Returns:

a boolean value

dispose

public void dispose()

Dispose this continuation. Should be called on invalidation.

disposed

public boolean disposed()

Return true if this continuation was disposed of

interpreterMatches

public boolean interpreterMatches(String interpreterId)

detachFromParent

public void detachFromParent()

clone

public Object clone()

Creates a clone of this WebContinuation without trying to clone the actual continuation, the user object or the disposer. TODO: Check continuation, user object, disposer for implementing Cloneable or Serializable.

Overrides:

clone in class Object

toString

public String toString()

Debugging method.

Assumes the receiving instance as the root of a tree and displays the tree of continuations.

Overrides:

toString in class Object

display

protected String display(int depth)

Debugging method.

Displays the receiving instance as if it is at the indent depth in the tree of continuations. Each level is indented 2 spaces.

Parameters:

depth - an int value