org.jscience.computing.graph.graphs
Class AbstractBaseGraph

java.lang.Object
  extended by org.jscience.computing.graph.graphs.AbstractGraph
      extended by org.jscience.computing.graph.graphs.AbstractBaseGraph
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, Graph
Direct Known Subclasses:
DefaultDirectedGraph, DirectedMultigraph, Multigraph, Pseudograph, SimpleDirectedGraph, SimpleGraph

public abstract class AbstractBaseGraph
extends AbstractGraph
implements Graph, java.lang.Cloneable, java.io.Serializable

The most general implementation of the Graph interface. Its subclasses add various restrictions to get more specific graphs. The decision whether it is directed or undirected is decided at construction time and cannot be later modified (see constructor for details).

This graph implementation guarantees deterministic vertex and edge set ordering (via LinkedHashMap and LinkedHashSet).

Since:
Jul 24, 2003
See Also:
Serialized Form

Constructor Summary
AbstractBaseGraph(EdgeFactory ef, boolean allowMultipleEdges, boolean allowLoops)
          Construct a new pseudograph.
 
Method Summary
 boolean addEdge(Edge e)
          Adds the specified edge to this graph.
 Edge addEdge(java.lang.Object sourceVertex, java.lang.Object targetVertex)
          Creates a new edge in this graph, going from the source vertex to the target vertex, and returns the created edge.
 boolean addVertex(java.lang.Object v)
          Adds the specified vertex to this graph if not already present.
 java.lang.Object clone()
          Returns a shallow copy of this graph instance.
 boolean containsEdge(Edge e)
          Returns true if this graph contains the specified edge.
 boolean containsVertex(java.lang.Object v)
          Returns true if this graph contains the specified vertex.
 int degreeOf(java.lang.Object vertex)
           
 java.util.Set edgeSet()
          Returns a set of the edges contained in this graph.
 java.util.List edgesOf(java.lang.Object vertex)
          Returns a list of all edges touching the specified vertex.
 java.util.List getAllEdges(java.lang.Object sourceVertex, java.lang.Object targetVertex)
          Returns a list of all edges connecting source vertex to target vertex if such vertices exist in this graph.
 Edge getEdge(java.lang.Object sourceVertex, java.lang.Object targetVertex)
          Returns an edge connecting source vertex to target vertex if such vertices and such edge exist in this graph.
 EdgeFactory getEdgeFactory()
          Returns the edge factory using which this graph creates new edges.
 java.util.List incomingEdgesOf(java.lang.Object vertex)
           
 int inDegreeOf(java.lang.Object vertex)
           
 boolean isAllowingLoops()
          Returns true if and only if self-loops are allowed in this graph.
 boolean isAllowingMultipleEdges()
          Returns true if and only if multiple edges are allowed in this graph.
 int outDegreeOf(java.lang.Object vertex)
           
 java.util.List outgoingEdgesOf(java.lang.Object vertex)
           
 boolean removeEdge(Edge e)
          Removes the specified edge from the graph.
 Edge removeEdge(java.lang.Object sourceVertex, java.lang.Object targetVertex)
          Removes an edge going from source vertex to target vertex, if such vertices and such edge exist in this graph.
 boolean removeVertex(java.lang.Object v)
          Removes the specified vertex from this graph including all its touching edges if present.
 void setEdgeListFactory(EdgeListFactory edgeListFactory)
          Set the EdgeListFactory to use for this graph.
 java.util.Set vertexSet()
          Returns a set of the vertices contained in this graph.
 
Methods inherited from class org.jscience.computing.graph.graphs.AbstractGraph
addAllEdges, addAllVertices, assertVertexExist, containsEdge, removeAllEdges, removeAllEdges, removeAllEdges, removeAllVertices, toString, toStringFromSets
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.jscience.computing.graph.Graph
addAllEdges, addAllVertices, containsEdge, removeAllEdges, removeAllEdges, removeAllVertices
 

Constructor Detail

AbstractBaseGraph

public AbstractBaseGraph(EdgeFactory ef,
                         boolean allowMultipleEdges,
                         boolean allowLoops)
Construct a new pseudograph. The pseudograph can either be directed or undirected, depending on the specified edge factory. A sample edge is created using the edge factory to see if the factory is compatible with this class of graph. For example, if this graph is a DirectedGraph the edge factory must produce DirectedEdges. If this is not the case, an IllegalArgumentException is thrown.

Parameters:
ef - the edge factory of the new graph.
allowMultipleEdges - whether to allow multiple edges or not.
allowLoops - whether to allow edges that are self-loops or not.
Throws:
java.lang.NullPointerException - if the specified edge factory is null.
Method Detail

getAllEdges

public java.util.List getAllEdges(java.lang.Object sourceVertex,
                                  java.lang.Object targetVertex)
Description copied from interface: Graph
Returns a list of all edges connecting source vertex to target vertex if such vertices exist in this graph. If any of the vertices does not exist or is null, returns null. If both vertices exist but no edges found, returns an empty list.

In undirected graphs, some of the returned edges may have their source and target vertices in the opposite order. In simple graphs the returned list is either singleton list or empty list.

Specified by:
getAllEdges in interface Graph
Parameters:
sourceVertex - source vertex of the edge.
targetVertex - target vertex of the edge.
Returns:
a list of all edges connecting source vertex to target vertex.
See Also:
Graph.getAllEdges(Object,Object)

isAllowingLoops

public boolean isAllowingLoops()
Returns true if and only if self-loops are allowed in this graph. A self loop is an edge that its source and target vertices are the same.

Returns:
true if and only if graph loops are allowed.

isAllowingMultipleEdges

public boolean isAllowingMultipleEdges()
Returns true if and only if multiple edges are allowed in this graph. The meaning of multiple edges is that there can be many edges going from vertex v1 to vertex v2.

Returns:
true if and only if multiple edges are allowed.

getEdge

public Edge getEdge(java.lang.Object sourceVertex,
                    java.lang.Object targetVertex)
Description copied from interface: Graph
Returns an edge connecting source vertex to target vertex if such vertices and such edge exist in this graph. Otherwise returns null. If any of the specified vertices is null returns null

In undirected graphs, the returned edge may have its source and target vertices in the opposite order.

Specified by:
getEdge in interface Graph
Parameters:
sourceVertex - source vertex of the edge.
targetVertex - target vertex of the edge.
Returns:
an edge connecting source vertex to target vertex.
See Also:
Graph.getEdge(Object,Object)

getEdgeFactory

public EdgeFactory getEdgeFactory()
Description copied from interface: Graph
Returns the edge factory using which this graph creates new edges. The edge factory is defined when the graph is constructed and must not be modified.

Specified by:
getEdgeFactory in interface Graph
Returns:
the edge factory using which this graph creates new edges.
See Also:
Graph.getEdgeFactory()

setEdgeListFactory

public void setEdgeListFactory(EdgeListFactory edgeListFactory)
Set the EdgeListFactory to use for this graph. Initially, a graph is created with a default implementation which always supplies an ArrayList with capacity 1.

Parameters:
edgeListFactory - factory to use for subsequently created edge lists (this call has no effect on existing edge lists)

addEdge

public Edge addEdge(java.lang.Object sourceVertex,
                    java.lang.Object targetVertex)
Description copied from interface: Graph
Creates a new edge in this graph, going from the source vertex to the target vertex, and returns the created edge. Some graphs do not allow edge-multiplicity. In such cases, if the graph already contains an edge from the specified source to the specified target, than this method does not change the graph and returns null.

The source and target vertices must already be contained in this graph. If they are not found in graph IllegalArgumentException is thrown.

This method creates the new edge e using this graph's EdgeFactory. For the new edge to be added e must not be equal to any other edge the graph (even if the graph allows edge-multiplicity). More formally, the graph must not contain any edge e2 such that e2.equals(e). If such e2 is found then the newly created edge e is abandoned, the method leaves this graph unchanged returns null.

Specified by:
addEdge in interface Graph
Parameters:
sourceVertex - source vertex of the edge.
targetVertex - target vertex of the edge.
Returns:
The newly created edge if added to the graph, otherwise null.
See Also:
Graph.addEdge(Object,Object)

addEdge

public boolean addEdge(Edge e)
Description copied from interface: Graph
Adds the specified edge to this graph. More formally, adds the specified edge, e, to this graph if this graph contains no edge e2 such that e2.equals(e). If this graph already contains such edge, the call leaves this graph unchanged and returns false. If the edge was added to the graph, returns true.

Some graphs do not allow edge-multiplicity. In such cases, if the graph already contains an edge going from e.getSource() vertex to e.getTarget() vertex, than this method does not change the graph and returns false.

The source and target vertices of the specified edge must already be in this graph. If this is not the case, IllegalArgumentException is thrown. The edge must also be assignment compatible with the class of the edges produced by the edge factory of this graph. If this is not the case ClassCastException is thrown.

Specified by:
addEdge in interface Graph
Parameters:
e - edge to be added to this graph.
Returns:
true if this graph did not already contain the specified edge.
See Also:
Graph.addEdge(Edge)

addVertex

public boolean addVertex(java.lang.Object v)
Description copied from interface: Graph
Adds the specified vertex to this graph if not already present. More formally, adds the specified vertex, v, to this graph if this graph contains no vertex u such that u.equals(v). If this graph already contains such vertex, the call leaves this graph unchanged and returns false. In combination with the restriction on constructors, this ensures that graphs never contain duplicate vertices.

Specified by:
addVertex in interface Graph
Parameters:
v - vertex to be added to this graph.
Returns:
true if this graph did not already contain the specified vertex.
See Also:
Graph.addVertex(Object)

clone

public java.lang.Object clone()
Returns a shallow copy of this graph instance. Neither edges nor vertices are cloned.

Overrides:
clone in class java.lang.Object
Returns:
a shallow copy of this set.
Throws:
java.lang.RuntimeException
See Also:
Object.clone()

containsEdge

public boolean containsEdge(Edge e)
Description copied from interface: Graph
Returns true if this graph contains the specified edge. More formally, returns true if and only if this graph contains an edge e2 such that e.equals(e2). If the specified edge is null returns false.

Specified by:
containsEdge in interface Graph
Parameters:
e - edge whose presence in this graph is to be tested.
Returns:
true if this graph contains the specified edge.
See Also:
Graph.containsEdge(Edge)

containsVertex

public boolean containsVertex(java.lang.Object v)
Description copied from interface: Graph
Returns true if this graph contains the specified vertex. More formally, returns true if and only if this graph contains a vertex u such that u.equals(v). If the specified vertex is null returns false.

Specified by:
containsVertex in interface Graph
Parameters:
v - vertex whose presence in this graph is to be tested.
Returns:
true if this graph contains the specified vertex.
See Also:
Graph.containsVertex(Object)

degreeOf

public int degreeOf(java.lang.Object vertex)
See Also:
UndirectedGraph.degreeOf(java.lang.Object)

edgeSet

public java.util.Set edgeSet()
Description copied from interface: Graph
Returns a set of the edges contained in this graph. The set is backed by the graph, so changes to the graph are reflected in the set. If the graph is modified while an iteration over the set is in progress, the results of the iteration are undefined.

The graph implementation may maintain a particular set ordering (e.g. via LinkedHashSet) for deterministic iteration, but this is not required. It is the responsibility of callers who rely on this behavior to only use graph implementations which support it.

Specified by:
edgeSet in interface Graph
Returns:
a set of the edges contained in this graph.
See Also:
Graph.edgeSet()

edgesOf

public java.util.List edgesOf(java.lang.Object vertex)
Description copied from interface: Graph
Returns a list of all edges touching the specified vertex. If no edges are touching the specified vertex returns an empty list.

Specified by:
edgesOf in interface Graph
Parameters:
vertex - the vertex for which a list of touching edges to be returned.
Returns:
a list of all edges touching the specified vertex.
See Also:
Graph.edgesOf(Object)

inDegreeOf

public int inDegreeOf(java.lang.Object vertex)
See Also:
DirectedGraph.inDegreeOf(java.lang.Object)

incomingEdgesOf

public java.util.List incomingEdgesOf(java.lang.Object vertex)
See Also:
DirectedGraph.incomingEdgesOf(java.lang.Object)

outDegreeOf

public int outDegreeOf(java.lang.Object vertex)
See Also:
DirectedGraph.outDegreeOf(java.lang.Object)

outgoingEdgesOf

public java.util.List outgoingEdgesOf(java.lang.Object vertex)
See Also:
DirectedGraph.outgoingEdgesOf(java.lang.Object)

removeEdge

public Edge removeEdge(java.lang.Object sourceVertex,
                       java.lang.Object targetVertex)
Description copied from interface: Graph
Removes an edge going from source vertex to target vertex, if such vertices and such edge exist in this graph. Returns the edge if removed or null otherwise.

Specified by:
removeEdge in interface Graph
Parameters:
sourceVertex - source vertex of the edge.
targetVertex - target vertex of the edge.
Returns:
The removed edge, or null if no edge removed.
See Also:
Graph.removeEdge(Object,Object)

removeEdge

public boolean removeEdge(Edge e)
Description copied from interface: Graph
Removes the specified edge from the graph. Removes the specified edge from this graph if it is present. More formally, removes an edge e2 such that e2.equals(e), if the graph contains such edge. Returns true if the graph contained the specified edge. (The graph will not contain the specified edge once the call returns).

If the specified edge is null returns false.

Specified by:
removeEdge in interface Graph
Parameters:
e - edge to be removed from this graph, if present.
Returns:
true if and only if the graph contained the specified edge.
See Also:
Graph.removeEdge(Edge)

removeVertex

public boolean removeVertex(java.lang.Object v)
Description copied from interface: Graph
Removes the specified vertex from this graph including all its touching edges if present. More formally, if the graph contains a vertex u such that u.equals(v), the call removes all edges that touch u and then removes u itself. If no such u is found, the call leaves the graph unchanged. Returns true if the graph contained the specified vertex. (The graph will not contain the specified vertex once the call returns).

If the specified vertex is null returns false.

Specified by:
removeVertex in interface Graph
Parameters:
v - vertex to be removed from this graph, if present.
Returns:
true if the graph contained the specified vertex; false otherwise.
See Also:
Graph.removeVertex(Object)

vertexSet

public java.util.Set vertexSet()
Description copied from interface: Graph
Returns a set of the vertices contained in this graph. The set is backed by the graph, so changes to the graph are reflected in the set. If the graph is modified while an iteration over the set is in progress, the results of the iteration are undefined.

The graph implementation may maintain a particular set ordering (e.g. via LinkedHashSet) for deterministic iteration, but this is not required. It is the responsibility of callers who rely on this behavior to only use graph implementations which support it.

Specified by:
vertexSet in interface Graph
Returns:
a set view of the vertices contained in this graph.
See Also:
Graph.vertexSet()