DirectedGraph (JSweet transpiler 2.2.0-SNAPSHOT API)

java.lang.Object
- org.jsweet.transpiler.util.DirectedGraph<T>

Type Parameters:

T - the types of the nodes in the graph

All Implemented Interfaces:

Iterable<T>, Collection<T>
```
public class DirectedGraph<T>
extends Object
implements Collection<T>
```
This class defines a directed graph collection type, that is to say a set of elements (aka nodes) linked together with directed edges. It is particularly useful for the topological sort, which is implemented as depicted in Wikipedia and this StackOverflow thread
Example of use:
```
 Graph<Integer> g = new Graph<Integer>();
 g.add(7, 5, 3, 11, 8, 2, 9, 10);
 g.buildEdges(new Comparator<Integer>() {
        @Override
        public int compare(Integer o1, Integer o2) {
                if (o1 == 5 && o2 == 3) {
                        return 1;
                }
                return 0;
        }
 });
 System.out.println(g.topologicalSort());
 
```
Prints out: [7, 3, 11, 8, 2, 9, 10, 5] (5 is pushed to the end because it is after 3). Note that the elements that are already in the right order remain unchanged.
The sorting method is deterministic, i.e. it always gives the same result and tries to minimize necessary changes.
Author:

Renaud Pawlak

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`DirectedGraph.Edge<T>` A generic object representing an edge in the graph.
`static class`	`DirectedGraph.Node<T>` An object representing the nodes of the graph.

Constructor Summary

Constructors
Constructor and Description

DirectedGraph()
Constructs an empty graph collection.

Constructors
Constructor and Description
`DirectedGraph()` Constructs an empty graph collection.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`add(T... elements)` Add a set of elements to the nodes of this graph.
`boolean`	`add(T element)` Adds an element to the nodes.
`boolean`	`addAll(Collection<? extends T> elements)` Adds a set of elements to the nodes of this graph.
`void`	`addEdge(T sourceElement, T destinationElement)` Add an edge between the given elements (nodes).
`void`	`addEdges(T sourceElement, T... destinationElements)` Adds some edges form the source elements to the given destination elements.
`<U extends T> void`	`buildEdges(Comparator<U> nodeComparator)` Automatically builds the edges between all the nodes of the graph by using the given comparator.
`void`	`clear()` Clears all the nodes of this graph.
`boolean`	`contains(Object o)` Tells if this graph contains the given object as a node.
`boolean`	`containsAll(Collection<?> c)` Tells if this graph contains the given collection as a node.
`static <T> void`	`dumpCycles(List<DirectedGraph.Node<T>> nodes, Function<T,String> toString)` Dumps the found cycles to System.out.
`boolean`	`equals(Object obj)` Equals two graphs.
`List<T>`	`getDestinationElements(T sourceElement)`
`List<T>`	`getSourceElements(T destinationElement)`
`boolean`	`hasEdge(T sourceElement, T destinationElement)` Tells if this graph contains an edge between the given source and the destination elements/nodes.
`int`	`hashCode()`
`boolean`	`isEmpty()` Returns true if this graph has no nodes.
`Iterator<T>`	`iterator()` Return an iterator to iterate on graph nodes.
`static void`	`main(String[] args)` Just for testing.
`boolean`	`remove(Object o)` Removes an object from the graph nodes (if exists).
`boolean`	`removeAll(Collection<?> c)` Removes all the objects from the graph nodes (if exists).
`boolean`	`retainAll(Collection<?> c)` Keeps only the elements of the given collection in the graph.
`int`	`size()` Returns the nodes count in this graph.
`Object[]`	`toArray()` Returns the graph's nodes as an array (not sorted).
`<U> U[]`	`toArray(U[] a)` Returns the graph's nodes as a well-typed array (not sorted).
`List<T>`	`topologicalSort(Consumer<DirectedGraph.Node<T>> cycleHandler)` Sorts this graph using a topological sort algorithm given in this StackOverflow thread.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection
parallelStream, removeIf, spliterator, stream

Methods inherited from interface java.lang.Iterable
forEach

- Constructor Detail
  - DirectedGraph
```
public DirectedGraph()
```
    Constructs an empty graph collection.
- Method Detail
  - addAll
```
public boolean addAll(Collection<? extends T> elements)
```
    Adds a set of elements to the nodes of this graph.
    
    Specified by:
    
    addAll in interface Collection<T>
  - add
```
public boolean add(T element)
```
    Adds an element to the nodes.
    
    Specified by:
    
    add in interface Collection<T>
  - clear
```
public void clear()
```
    Clears all the nodes of this graph.
    
    Specified by:
    
    clear in interface Collection<T>
  - contains
```
public boolean contains(Object o)
```
    Tells if this graph contains the given object as a node.
    
    Specified by:
    
    contains in interface Collection<T>
  - containsAll
```
public boolean containsAll(Collection<?> c)
```
    Tells if this graph contains the given collection as a node.
    
    Specified by:
    
    containsAll in interface Collection<T>
  - equals
```
public boolean equals(Object obj)
```
    Equals two graphs.
    
    Specified by:
    
    equals in interface Collection<T>
    
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in interface Collection<T>
    
    Overrides:
    
    hashCode in class Object
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this graph has no nodes.
    
    Specified by:
    
    isEmpty in interface Collection<T>
  - iterator
```
public Iterator<T> iterator()
```
    Return an iterator to iterate on graph nodes.
    
    Specified by:
    
    iterator in interface Iterable<T>
    
    Specified by:
    
    iterator in interface Collection<T>
  - remove
```
public boolean remove(Object o)
```
    Removes an object from the graph nodes (if exists).
    
    Specified by:
    
    remove in interface Collection<T>
  - removeAll
```
public boolean removeAll(Collection<?> c)
```
    Removes all the objects from the graph nodes (if exists).
    
    Specified by:
    
    removeAll in interface Collection<T>
  - retainAll
```
public boolean retainAll(Collection<?> c)
```
    Keeps only the elements of the given collection in the graph.
    
    Specified by:
    
    retainAll in interface Collection<T>
  - size
```
public int size()
```
    Returns the nodes count in this graph.
    
    Specified by:
    
    size in interface Collection<T>
  - toArray
```
public Object[] toArray()
```
    Returns the graph's nodes as an array (not sorted).
    
    Specified by:
    
    toArray in interface Collection<T>
  - toArray
```
public <U> U[] toArray(U[] a)
```
    Returns the graph's nodes as a well-typed array (not sorted).
    
    Specified by:
    
    toArray in interface Collection<T>
  - add
```
public void add(T... elements)
```
    Add a set of elements to the nodes of this graph.
  - addEdge
```
public void addEdge(T sourceElement,
                    T destinationElement)
```
    Add an edge between the given elements (nodes).
    
    Parameters:
    
    sourceElement - the source element/node
    
    destinationElement - the destination element/node
  - buildEdges
```
public <U extends T> void buildEdges(Comparator<U> nodeComparator)
```
    Automatically builds the edges between all the nodes of the graph by using the given comparator. If the comparator returns 0, then no edge is constructor between the compared nodes.
    
    Parameters:
    
    nodeComparator - a comparator which is used to build the edges
  - addEdges
```
public void addEdges(T sourceElement,
                     T... destinationElements)
```
    Adds some edges form the source elements to the given destination elements.
    
    Parameters:
    
    sourceElement - the source of the edges
    
    destinationElements - the destination elements of the edges
  - hasEdge
```
public boolean hasEdge(T sourceElement,
                       T destinationElement)
```
    Tells if this graph contains an edge between the given source and the destination elements/nodes.
    
    Parameters:
    
    sourceElement - the source node
    
    destinationElement - the destination node
    
    Returns:
    
    true if an edge is found, false otherwise
  - getDestinationElements
```
public List<T> getDestinationElements(T sourceElement)
```
  - getSourceElements
```
public List<T> getSourceElements(T destinationElement)
```
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - topologicalSort
```
public List<T> topologicalSort(Consumer<DirectedGraph.Node<T>> cycleHandler)
```
    Sorts this graph using a topological sort algorithm given in this StackOverflow thread.
    
    Returns:
    
    the list of nodes, sorted according to the topological sort
    
    Throws:
    
    CycleFoundException - thrown if a cycle is found in the graph (in that case no topological sort is possible)
  - dumpCycles
```
public static <T> void dumpCycles(List<DirectedGraph.Node<T>> nodes,
                                  Function<T,String> toString)
```
    Dumps the found cycles to System.out.
    
    Parameters:
    
    nodes - the nodes in which to look for cycles
    
    toString - the element's toString function
  - main
```
public static void main(String[] args)
```
    Just for testing.

Class DirectedGraph<T>

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Constructor Detail

DirectedGraph

Method Detail

addAll

add

clear

contains

containsAll

equals

hashCode

isEmpty

iterator

remove

removeAll

retainAll

size

toArray

toArray

add

addEdge

buildEdges

addEdges

hasEdge

getDestinationElements

getSourceElements

toString

topologicalSort

dumpCycles

main