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org.dbreplicator.graph
Interface DGraph

All Known Implementing Classes:

DirectedGraph, JbDirectedGraph

public interface DGraph

A directed graph with weighted edges. The weights are non-negative. The directed graph can contain any object as a vertex. Null references are not allowed. A vertex can have a self loop, i. e. an edge that leaves from and enters the same vertex. There cannot be more than Integer.MAX_VALUE vertices in the directed graph. Removing vertices from the directed graph is not supported. The directed graph is not thread-safe: it must not be used concurrently by multiple threads.

The behavior of the directed graph is not specified if the value of an object is changed in a manner that affects comparisons by the equals(object) method while the object is a vertex in the graph. It is prohibited for a directed graph to contain itself as a vertex.

Method Summary

boolean	addEdge(java.lang.Object first, java.lang.Object second, int weight) Adds an edge of a specified weight from the vertex first to the vertex second.
boolean	addVertex(java.lang.Object object) Adds the specified vertex to this directed graph if the vertex is not null and the vertex is not already present in this directed graph.
java.lang.Object[]	adjacentsOf(java.lang.Object ob) Returns an array containing all vertices that are adjacent to the specified vertex.
int	edgeCount() Returns the number of edges in this directed graph.
int	edgeWeight() Returns the sum of the weights of all edges in this directed graph.
int	edgeWeight(java.lang.Object first, java.lang.Object second) Returns the weight of the edge that leaves from the vertex first and enters the vertex second.
boolean	equals(java.lang.Object obj)
boolean	hasCycle() Returns true if there is a cycle in the directed graph.
boolean	hasEdge(java.lang.Object first, java.lang.Object second) Returns true if this directed graph contains an edge that leaves from the vertex first and enters the vertex second.
boolean	hasEdges() Returns true if there are edges in this directed graph.
int	hashCode() Returns the hash code value for this directed graph.
boolean	hasVertex(java.lang.Object ob) Returns true if this directed graph contains the specified vertex.
boolean	hasVertices()
int	inDegree(java.lang.Object object) Returns the number of edges that enter the specified vertex.
boolean	isIsolated(java.lang.Object ob) Returns true if the specified vertex is isolated.
boolean	isLinearList() Returns true if the directed graph forms a linear list.
int	outDegree(java.lang.Object vertex) Returns the number of edges that leave from the specified vertex.
java.lang.Object[]	topologicalSort() Returns an array of all of the vertices in this directed graph in some topological sort order.
int	vertexCount() Returns the number of vertices in this directed graph.
java.lang.Object[]	verticesToArray() Returns an array containing all vertices in this directed graph.

Method Detail

equals

boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

int hashCode()

Returns the hash code value for this directed graph. The hash code of a directed graph is defined to be the sum of the hash codes of the vertices in the directed graph. The sum is allowed to overflow if needed. This definition ensures that if s1.equals(s2) then s1.hashCode() == s2.hashCode() for any two directed graphs s1 and s2, as required by the general contract of the java.lang.Object.hashCode method.

Overrides:

hashCode in class java.lang.Object

addVertex

boolean addVertex(java.lang.Object object)
                  throws RepException

Adds the specified vertex to this directed graph if the vertex is not null and the vertex is not already present in this directed graph. More formally, adds the specified vertex obj to this directed graph if obj != null and this directed graph contains no vertex e such that obj.equals(e). The number of vertices in this directed graph may not exceed Integer.MAX_VALUE.

Throws:

RepException

hasVertex

boolean hasVertex(java.lang.Object ob)

Returns true if this directed graph contains the specified vertex. More formally, returns true if and only if obj != null and this directed graph contains an vertex e such that obj.equals(e).

hasVertices

boolean hasVertices()

vertexCount

int vertexCount()

Returns the number of vertices in this directed graph.

verticesToArray

java.lang.Object[] verticesToArray()

Returns an array containing all vertices in this directed graph. The vertices need not be in any special order.

The returned array will be "safe" in that no references to it are maintained by this directed graph. In other words, this method must allocate a new array even if this collection is backed by an array. The caller is thus free to modify the returned array.

Returns:

an array containing all vertices in this directed graph.

addEdge

boolean addEdge(java.lang.Object first,
                java.lang.Object second,
                int weight)
                throws RepException

Adds an edge of a specified weight from the vertex first to the vertex second.

Throws:

RepException

hasEdge

boolean hasEdge(java.lang.Object first,
                java.lang.Object second)

Returns true if this directed graph contains an edge that leaves from the vertex first and enters the vertex second.

edgeWeight

int edgeWeight(java.lang.Object first,
               java.lang.Object second)

Returns the weight of the edge that leaves from the vertex first and enters the vertex second.

inDegree

int inDegree(java.lang.Object object)
             throws RepException

Returns the number of edges that enter the specified vertex.

Throws:

RepException

outDegree

int outDegree(java.lang.Object vertex)
              throws RepException

Returns the number of edges that leave from the specified vertex.

Throws:

RepException

adjacentsOf

java.lang.Object[] adjacentsOf(java.lang.Object ob)
                               throws RepException

Returns an array containing all vertices that are adjacent to the specified vertex. A vertex v is adjacent to a vertex u if there is an edge that leaves from u and enters v.

The returned array will be "safe" in that no references to it are maintained by this directed graph. In other words, this method must allocate a new array even if this collection is backed by an array. The caller is thus free to modify the returned array.

Throws:

RepException

isIsolated

boolean isIsolated(java.lang.Object ob)
                   throws RepException

Returns true if the specified vertex is isolated. A vertex is isolated if there are no edges leaving from or entering the vertex, or the only edge leaving from the vertex enters the vertex itself and the only edge entering the vertex leaves from the vertex itself.

Throws:

RepException

hasEdges

boolean hasEdges()

Returns true if there are edges in this directed graph.

Returns:

true if there are edges in this directed graph.

edgeCount

int edgeCount()

Returns the number of edges in this directed graph. If this directed graph contains more than Integer.MAX_VALUE edges, returns Integer.MAX_VALUE.

edgeWeight

int edgeWeight()

Returns the sum of the weights of all edges in this directed graph. If the sum is more than Integer.MAX_VALUE, returns Integer.MAX_VALUE.

topologicalSort

java.lang.Object[] topologicalSort()

Returns an array of all of the vertices in this directed graph in some topological sort order.

The returned array will be "safe" in that no references to it are maintained by this directed graph. In other words, this method must allocate a new array even if this collection is backed by an array. The caller is thus free to modify the returned array.

Returns:

an array of all of the vertices in this directed graph in some topological sort order. Returns null if no topological sort is possible.

hasCycle

boolean hasCycle()

Returns true if there is a cycle in the directed graph.

Returns:

true if there is a cycle in the directed graph.

isLinearList

boolean isLinearList()

Returns true if the directed graph forms a linear list. A directed graph with no vertices or one vertex without a self loop is also considered to form a linear list.