org.openide.util

Class TopologicalSortException

java.lang.Object

java.lang.Throwable

java.lang.Exception

org.openide.util.TopologicalSortException

All Implemented Interfaces:

Serializable

public final class TopologicalSortException
extends Exception

Exception that signals that a topological sort failed due to unsortable nature of the graph and that provides support for reporting and recovering from that state.

Since:

3.30

See Also:

BaseMutexUtilities#topologicalSort, Serialized Form

Method Summary

Modifier and Type	Method and Description
String	getMessage()
List	partialSort() Because the full sort was not possible, this methods returns the best possible substitute for it that is available.
void	printStackTrace(PrintStream s) Adds description why the graph cannot be sorted.
void	printStackTrace(PrintWriter w) Adds description why the graph cannot be sorted.
Set[]	topologicalSets() As the full topological sort cannot be finished due to cycles in the graph this methods performs a partition topological sort.
String	toString()
Set[]	unsortableSets() The topological sort could not be finished as there are some objects that are mutually refering to each other.

Methods inherited from class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getStackTrace, getSuppressed, initCause, printStackTrace, setStackTrace

Methods inherited from class java.lang.Object

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

Method Detail

partialSort

public final List partialSort()

Because the full sort was not possible, this methods returns the best possible substitute for it that is available.

Returns:

list of partially sorted objects, the list can be freely modified

unsortableSets

public final Set[] unsortableSets()

The topological sort could not be finished as there are some objects that are mutually refering to each other. This methods finds such objects and partition them into separate sets. All objects in one set (transitively) refer to each other and thus prevent the sort from succeding. As there can be more of such "unsortable sets" an array of them is returned.

Returns:

array of sets that contain some of the original objects, result shall not be modified

getMessage

public String getMessage()

Overrides:

getMessage in class Throwable

toString

public String toString()

Overrides:

toString in class Throwable

printStackTrace

public final void printStackTrace(PrintWriter w)

Adds description why the graph cannot be sorted.

Overrides:

printStackTrace in class Throwable

Parameters:

w - writer to write to

printStackTrace

public final void printStackTrace(PrintStream s)

Adds description why the graph cannot be sorted.

Overrides:

printStackTrace in class Throwable

Parameters:

s - stream to write to

topologicalSets

public final Set[] topologicalSets()

As the full topological sort cannot be finished due to cycles in the graph this methods performs a partition topological sort.

First of all it identifies unsortable parts of the graph and partitions the graph into sets of original objects. Each set contains objects that are mutually unsortable (there is a cycle between them). Then the topological sort is performed again on those sets, this sort succeeds because the graph of sets is DAG (all problematic edges were only between objects now grouped inside the sets) and the result forms the return value of this method.

Returns:

array of sorted sets that contain the original objects, each object from the original collection is exactly in one set, result shall not be modified