From VisualWorks® NonCommercial, 7.6 of March 3, 2008 on October 24, 2008 at 10:05:18 am (Dialog confirm: 'You are filing-in a Parcel source file!\\While this is possible it will not have\the same effect as loading the parcel.\None of the Parcel''s prerequisites will\be loaded and none of its load actions\will be performed.\\Are you sure you want to file-in?' withCRs) ifFalse: [self error: 'Parcel file-in abandoned. Choose terminate or close.'] GraphTest Smalltalk SUnit.TestCase false none CS411 CS411Graphs SimpleGraphReader Smalltalk Core.Object false none stream graphSpecies CS411 CS411Graphs SimpleGraphReader This class reads Graphs from a formatted ReadStream. The format of the stream is quite rigid. Each graph in the stream is enclosed with lines of the form: graph <graph name> ...body goes here... end where <graph name> is replaced by the name of the graph without the angle brackets (for example, graph Network). The body of the graph can contain either node or edge statements of the form node <node name> edge <node name> <node name> Nodes must be defined in the file _before_ they can be used in an edge. When nextGraph is sent to a SimpleGraphReader it skips anything up to a "graph" statement. That way if there is an error processing one graph in a stream, you can continue with the next graph. See the test class method category for some examples. Instance Variables: stream <ReadStream> the read stream graphSpecies <Class> The species of the graph to be created PrePostVisitor Smalltalk Core.Object false none CS411 CS411Graphs PrePostVisitor An abstract class demonstrating the interface required of all graph traveral visitors. This class implements the visiting methods as "no-ops". Concrete subclasses would implement preVisit: and/or postVisit: to perform some operation upon visiting a node. Instance Variables: CollectingVisitor Smalltalk PrePostVisitor false none nodes CS411 CS411Graphs GraphElement Smalltalk Core.Object false none value graph CS411 CS411Graphs GraphElement A container for an arbitrary object (should use ValueModel but it is really intended for GUI applications). Instance Variables: value <Object> the contents of this holder Vertex Smalltalk GraphElement false none incidentEdges CS411 CS411Graphs Vertex A vertex intended for use in a graph which is represented using an adjacency list structure. Instance Variables: incidentEdges <SequenceableCollection> collection of edges incident on this vertex Edge Smalltalk GraphElement false none vertex1 vertex2 CS411 CS411Graphs Edge An undirected edge intended for Graphs implemented using the adjacency list structure. Instance Variables: vertex1 <Vertex> one endpoint of this edge vertex2 <Vertex> another endpoint of this edge Graph Smalltalk Core.Object false none vertices edges CS411 CS411Graphs Graph An abstract class supporting a protocol for undirected graphs (although subclasses might include directed graphs). Instance Variables: vertices <SequenceableCollection> the vertices in the graph edges <SequenceableCollection> the edges in the graph GraphTest sample graphs aCompleteGraph "Used by various tests" | g v | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'. g insertEdgeConnecting: (v at: 1) and: (v at: 3) containing: '2'. g insertEdgeConnecting: (v at: 2) and: (v at: 3) containing: '4'. ^g aCompleteGraphWithLoops "Used by various tests" | g v | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'. g insertEdgeConnecting: (v at: 1) and: (v at: 3) containing: '2'. g insertEdgeConnecting: (v at: 2) and: (v at: 3) containing: '4'. g insertEdgeConnecting: (v at: 2) and: (v at: 2) containing: '5'. g insertEdgeConnecting: (v at: 3) and: (v at: 3) containing: '6'. ^g aDisconnectedGraph "Used by various tests" | g v | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). v add: (g insertVertexContaining: 'D'). v add: (g insertVertexContaining: 'E'). g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'. g insertEdgeConnecting: (v at: 2) and: (v at: 1) containing: '2'. g insertEdgeConnecting: (v at: 2) and: (v at: 3) containing: '3'. g insertEdgeConnecting: (v at: 4) and: (v at: 5) containing: '4'. ^g aGraphWithLoops "Used by various tests" | g v | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). v add: (g insertVertexContaining: 'D'). v add: (g insertVertexContaining: 'E'). g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'. g insertEdgeConnecting: (v at: 1) and: (v at: 3) containing: '2'. g insertEdgeConnecting: (v at: 2) and: (v at: 2) containing: '3'. g insertEdgeConnecting: (v at: 4) and: (v at: 5) containing: '4'. g insertEdgeConnecting: (v at: 5) and: (v at: 1) containing: '5'. g insertEdgeConnecting: (v at: 3) and: (v at: 5) containing: '6'. g insertEdgeConnecting: (v at: 2) and: (v at: 2) containing: '7'. ^g aGraphWithParallelEdges "Used by various tests" | g v | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). v add: (g insertVertexContaining: 'D'). v add: (g insertVertexContaining: 'E'). g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'. g insertEdgeConnecting: (v at: 2) and: (v at: 1) containing: '2'. g insertEdgeConnecting: (v at: 2) and: (v at: 3) containing: '3'. g insertEdgeConnecting: (v at: 4) and: (v at: 5) containing: '4'. g insertEdgeConnecting: (v at: 3) and: (v at: 5) containing: '5'. ^g anAlmostCompleteGraphWithLoops "Used by various tests" | g v | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). v add: (g insertVertexContaining: 'D'). g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'. g insertEdgeConnecting: (v at: 1) and: (v at: 3) containing: '2'. g insertEdgeConnecting: (v at: 1) and: (v at: 1) containing: '3'. g insertEdgeConnecting: (v at: 2) and: (v at: 3) containing: '4'. g insertEdgeConnecting: (v at: 2) and: (v at: 4) containing: '5'. g insertEdgeConnecting: (v at: 3) and: (v at: 4) containing: '6'. ^g aSimpleGraph "Used by various tests" | g v | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). v add: (g insertVertexContaining: 'D'). v add: (g insertVertexContaining: 'E'). g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'. g insertEdgeConnecting: (v at: 1) and: (v at: 3) containing: '2'. g insertEdgeConnecting: (v at: 4) and: (v at: 5) containing: '4'. g insertEdgeConnecting: (v at: 5) and: (v at: 1) containing: '5'. g insertEdgeConnecting: (v at: 3) and: (v at: 5) containing: '6'. ^g GraphTest tests test0 "To pass this test you have defined the class ALGraph" self assert: #{ALGraph} binding notNil test1 "To pass this test you must have correctly implemented insertVertexContaining:, insertEdgeConnecting:and:containing:" | g v1 v2 e1 e2 | g := self graphSpecies new. v1 := g insertVertexContaining: 'A'. v2 := g insertVertexContaining: 'B'. e1 := g insertEdgeConnecting: v1 and: v2 containing: '1'. e2 := g insertEdgeConnecting: v1 and: v1 containing: '2'. self assert: g edges size = 2. self assert: g vertices size = 2. self assert: (g vertices contains: [:v | v == v1]). self assert: (g vertices contains: [:v | v == v2]). self assert: (g edges contains: [:e | e == e1]). self assert: (g edges contains: [:e | e == e2]). self assert: v1 graph = g & (v2 graph = g). self assert: e1 graph = g & (e2 graph = g). self assert: (v1 incidentEdges includes: e1) & (v1 incidentEdges includes: e2). self assert: (v2 incidentEdges includes: e1) test2 "To pass this test you must have correctly implemented endVertices:, adjacentVertices:" | g v1 v2 e1 e2 | g := self graphSpecies new. v1 := g insertVertexContaining: 'A'. v2 := g insertVertexContaining: 'B'. e1 := g insertEdgeConnecting: v1 and: v2 containing: '1'. e2 := g insertEdgeConnecting: v1 and: v1 containing: '2'. self assert: g edges size = 2. self assert: g vertices size = 2. self assert: ((g endVertices: e1) includes: v1). self assert: ((g endVertices: e1) includes: v2). self assert: (g edgeContaining: '1') == e1. self assert: (g edgeContaining: '2') == e2. self assert: ((g adjacentVertices: v1) includes: v2). self assert: ((g adjacentVertices: v1) includes: v1). self assert: (g vertexContaining: 'A') == v1. self assert: (g vertexContaining: 'B') == v2. self assert: (g isVertex: v1 adjacentTo: v1). self assert: (g isVertex: v1 adjacentTo: v2). self assert: (g isVertex: v2 adjacentTo: v1). self deny: (g isVertex: v2 adjacentTo: v2) test3 "To pass this test you must have correctly implemented degree:, removeEdge:, removeVertex:, vertexOppositeTo:on:" | g v e | g := self graphSpecies new. v := OrderedCollection new. v add: (g insertVertexContaining: 'A'). v add: (g insertVertexContaining: 'B'). v add: (g insertVertexContaining: 'C'). v add: (g insertVertexContaining: 'D'). v add: (g insertVertexContaining: 'E'). e := OrderedCollection new. e add: (g insertEdgeConnecting: (v at: 1) and: (v at: 2) containing: '1'). e add: (g insertEdgeConnecting: (v at: 1) and: (v at: 3) containing: '2'). e add: (g insertEdgeConnecting: (v at: 2) and: (v at: 2) containing: '3'). e add: (g insertEdgeConnecting: (v at: 4) and: (v at: 5) containing: '4'). e add: (g insertEdgeConnecting: (v at: 5) and: (v at: 1) containing: '5'). e add: (g insertEdgeConnecting: (v at: 3) and: (v at: 5) containing: '6'). e add: (g insertEdgeConnecting: (v at: 2) and: (v at: 2) containing: '7'). self assert: (g degree: (v at: 5)) = 3. self assert: (g degree: (v at: 1)) = 3. self assert: (g degree: (v at: 2)) = 5. self assert: (g vertexOppositeTo: (v at: 2) on: (e at: 7)) == (v at: 2). "vertex two has a loop" self assert: (g removeEdge: (g edgeContaining: '7')) == (e at: 7). self assert: (g degree: (v at: 2)) = 3. "re-insert the loop" e at: 7 put: (g insertEdgeConnecting: (v at: 2) and: (v at: 2) containing: '7'). self assert: g edges size = 7. self assert: g vertices size = 5. self assert: (g removeVertex: (g vertexContaining: 'E')) == (v at: 5). self assert: (g vertices includes: (v at: 5)) not. self deny: ((g edges includes: (e at: 4)) | (g edges includes: (e at: 5)) | (g edges includes: (e at: 6))) . self assert: (g removeVertex: (g vertexContaining: 'C')) == (v at: 3). "remove a different vertex" self assert: (g vertices includes: (v at: 3)) not. self assert: (g edges contains: [:edge | (edge == (e at: 6) | edge) == (e at: 2)]) not. "Remove a vertex with a self loop" self assert: (g removeVertex: (g vertexContaining: 'B')) == (v at: 2). self assert: g edges size = 0. test4 "To pass this test you must have correctly implemented isSimple and isComplete" | g | g := self aGraphWithLoops. self deny: g isSimple. g := self aGraphWithParallelEdges. self deny: g isSimple. g := self aSimpleGraph. self assert: g isSimple. g := self aCompleteGraph. self assert: g isComplete. g := self aSimpleGraph. self deny: g isComplete. g := self aCompleteGraphWithLoops. self assert: g isComplete. g := self anAlmostCompleteGraphWithLoops. self deny: g isComplete test5 "To pass this test you must have correctly implemented depthFirstTraveralFrom:visitor:" | visitor g | visitor := CollectingVisitor new. g := self aDisconnectedGraph. g depthFirstTraversalFrom: (g vertexContaining: 'E') visitor: visitor. self assert: visitor nodes size = 2. self assert: (visitor nodes includes: (g vertexContaining: 'E')). self assert: (visitor nodes includes: (g vertexContaining: 'D')). visitor := CollectingVisitor new. g depthFirstTraversalFrom: (g vertexContaining: 'B') visitor: visitor. self assert: visitor nodes size = 3. self assert: (visitor nodes includes: (g vertexContaining: 'A')). self assert: (visitor nodes includes: (g vertexContaining: 'B')). self assert: (visitor nodes includes: (g vertexContaining: 'C')). " now check ordering " g := self aSimpleGraph. visitor := CollectingVisitor new. g depthFirstTraversalFrom: (g vertexContaining: 'B') visitor: visitor. self assert: (visitor nodes indexOf: (g vertexContaining: 'D')) < (visitor nodes indexOf: (g vertexContaining: 'E')). self assert: (visitor nodes indexOf: (g vertexContaining: 'E')) < (visitor nodes indexOf: (g vertexContaining: 'A')). self assert: (visitor nodes indexOf: (g vertexContaining: 'C')) < (visitor nodes indexOf: (g vertexContaining: 'A')). self assert: (visitor nodes indexOf: (g vertexContaining: 'A')) < (visitor nodes indexOf: (g vertexContaining: 'B')) test6 "To pass this test you must have correctly implemented isConnected" | g | g := self aGraphWithLoops. self assert: g isConnected. g := self aGraphWithParallelEdges. self assert: g isConnected. g := self aCompleteGraph. self assert: g isConnected. g := self aSimpleGraph. self assert: g isConnected. g := self aDisconnectedGraph. self assert: g isConnected not GraphTest accessing graphSpecies "modify this method to return your class" ^#{ALGraph} binding value SimpleGraphReader private graphSpecies: aGraphSubclass graphSpecies := aGraphSubclass on: aReadStream stream := aReadStream. ^self processEdgeLine: line inGraph: aGraph | v1 v2 space | space := line findString: ' ' startingAt: 6. v1 := aGraph vertexContaining: (line copyFrom: 6 to: space-1). v2 := aGraph vertexContaining: (line copyFrom: space+1 to: line size). aGraph insertEdgeConnecting: v1 and: v2 containing: nil. processNodeLine: line inGraph: aGraph | name | name := line copyFrom: 6 to: line size. aGraph insertVertexContaining: name. SimpleGraphReader reading nextGraph | result line | stream throughAll: 'graph '. result := graphSpecies new. Transcript show: 'reading ' , (stream upTo: Character cr); cr. "ignore the name for now since Graphs don't support naming" line := stream upTo: Character cr. [('end*' match: line) or: [stream atEnd]] whileFalse: [ ('node *' match: line) ifTrue: [self processNodeLine: line inGraph: result]. ('edge *' match: line) ifTrue: [self processEdgeLine: line inGraph: result]. line := stream upTo: Character cr. ]. ^result SimpleGraphReader class instance creation on: aReadStream withGraphSpecies: aGraphSubclass | instance | instance := super new on: aReadStream. instance graphSpecies: aGraphSubclass. ^instance SimpleGraphReader class test test1 | graphDef rs reader | "self test1" graphDef := ' graph Graph1 node Hello node Goodbye node farewell edge Hello Goodbye edge Goodbye farewell end '. rs := ReadStream on: graphDef. reader := self on: rs withGraphSpecies: ALGraph. reader nextGraph inspect. PrePostVisitor visiting postVisit: aVertex ^self preVisit: aVertex ^self CollectingVisitor initialize-release initialize nodes := OrderedCollection new. CollectingVisitor visiting postVisit: aVertex nodes add: aVertex CollectingVisitor accessing nodes ^nodes CollectingVisitor class instance creation new ^super new initialize GraphElement accessing graph ^graph graph: aGraph graph := aGraph value ^value value: aValue value := aValue GraphElement printing printOn: aStream super printOn: aStream. aStream nextPut: $(. aStream nextPutAll: (self value printString). aStream nextPut: $). Vertex accessing incidentEdges ^incidentEdges Vertex initialize-release initialize incidentEdges := OrderedCollection new. ^self Vertex edges addEdge: anEdge incidentEdges add: anEdge removeEdge: anEdge "Remove anEdge from our incident edges and return it" ^incidentEdges remove: anEdge Vertex class instance creation new ^super new initialize Edge accessing mateFor: aVertex "Answer the vertex opposite to aVertex on this edge" ^aVertex = vertex1 ifTrue: [vertex2] ifFalse: [vertex1] vertex1 ^vertex1 vertex2 ^vertex2 Edge private with: v1 and: v2 vertex1 := v1. vertex2 := v2. vertex1 addEdge: self. vertex2 addEdge: self. ^self Edge testing isParallelTo: other ^self vertex1 == other vertex1 & self vertex2 == other vertex2 or: [self vertex1 == other vertex2 & self vertex2 == other vertex1] Edge class instance creation newWith: vertex1 and: vertex2 | instance | instance := self new. instance with: vertex1 and: vertex2. ^instance Graph initialize-release initialize edges := OrderedCollection new. vertices := OrderedCollection new. ^self Graph adding/removing insertEdgeConnecting: vertex1 and: vertex2 containing: object "insert the specified edge and return it" self subclassResponsibility insertVertexContaining: anObject "Insert the specified vertex and return it" self subclassResponsibility removeEdge: anEdge "remove anEdge from the graph and answer the removed edge" self subclassResponsibility removeVertex: aVertex "remove aVertex from the graph and answer aVertex" self subclassResponsibility Graph vertex properties adjacentVertices: aVertex "Answer a SequenceableCollection (of some kind) which contains all vertices adjacent to the one supplied" self subclassResponsibility degree: aVertex self subclassResponsibility incidentEdges: aVertex "Answer a SequenceableCollection (of some kind) containing all edges incident on aVertex" self subclassResponsibility isVertex: vertex1 adjacentTo: vertex2 "Answer true if vertex1 is adjacent to vertex2, false otherwise" ^(self adjacentVertices: vertex1) includes: vertex2 vertexContaining: anObject ^self vertices detect: [ :vertex | vertex value = anObject ] vertexOppositeTo: aVertex on: anEdge "Answer the vertext opposite to aVertex on anEdge" self subclassResponsibility Graph accessing edges "Do not modify the collection returned by this method!" ^edges vertices "Do not modify the collection returned by this method!" ^vertices Graph traversals depthFirstTraversalFrom: aVertex visitor: aPrePostVisitor "Traverse our edges/nodes, starting at aVertex, in depth-first order. Before visiting the nodes connected to a node send preVisit: to aPrePostVisitor and after visiting all nodes connected to a node send postVisit: to aPrePostVisitor. A given node will never be pre-visited or post-visited more than once. Answer self." self subclassResponsibility Graph graph properties isComplete "A graph is complete if every node is adjacent to every other node (except, possibly, itself)" self subclassResponsibility isConnected "A graph is connected if there is a path from any node to any other node. Hint: A graph is connected if and only if a traversal starting from an arbitrary node will visit every node. Complete your depth first traversal method first. Then, in this method, create an instance of CollectingVisitor, pass it to your traversal method and when the traversal returns check to make sure that every node was visited (the visitor will collect nodes once and only once so you only have to check the size)." self subclassResponsibility isSimple "A graph is simple if: it contains no self loops (edge which starts and ends on the same vertex) it contains to parallel edges (two edges which start at the same place and end at the same place)" self subclassResponsibility Graph edge properties edgeContaining: anObject ^self edges detect: [ :edge | edge value = anObject ]. endVertices: anEdge "Answer a SequenceableCollection (of some kind) which contains the two end vertices of the supplied edge" self subclassResponsibility Graph class instance creation new ^super new initialize "Imported Classes:" self error: 'Attempting to file-in parcel imports. Choose terminate or close' Object Core false none Kernel-Objects Kernel-Objects TestCase SUnit Core.Object false none testSelector SUnit SUnitToo