Graph (Closure Compiler)

java.lang.Object
- com.google.javascript.jscomp.graph.Graph<N,E>

Type Parameters:
N - Value type that the graph node stores.
E - Value type that the graph edge stores.

All Implemented Interfaces:

AdjacencyGraph<N,E>

Direct Known Subclasses:

DiGraph, UndiGraph
```
public abstract class Graph<N,E>
extends Object
implements AdjacencyGraph<N,E>
```
The base generic class for graph-like data structure and algorithms in the compiler.
Nodes and edges in the graph can store a piece of data that this graph is used to represent. For example, a variable interference graph might store a variable in the node. This piece of data can be accessed with GraphNode.getValue() and Graph.GraphEdge.getValue().
Algorithms and analysis can annotate information on the nodes and edges using GraphNode.getValue() and Graph.GraphEdge.getValue(). For example, a graph coloring algorithm can store the color as an annotation. If multiple analyses are required, it is up to the user of the analysis to save the annotated solution between passes.
We implemented our own graph data structure (as opposed to using com.google.common.graph) for two reasons. First, aside from the node's label value, we would like to annotate information on the nodes and edges. Using a map to annotate would introduce too much overhead during fix point analysis. Also, com.google.common.graph does not support labeling of edges. Secondly, not using another external package would limit our dependencies.
TODO(user): All functionality for removing nodes and edges.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static interface Graph.GraphEdge<N,E>
A generic edge.

Nested Classes
Modifier and Type	Class and Description
`static interface`	`Graph.GraphEdge<N,E>` A generic edge.

Constructor Summary

Constructors
Constructor and Description

Graph()

Constructors
Constructor and Description
`Graph()`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clearEdgeAnnotations()` Makes each edge's annotation null.
`void`	`clearNodeAnnotations()` Makes each node's annotation null.
`abstract void`	`connect(N n1, E edge, N n2)` Connects two nodes in the graph with an edge.
`void`	`connectIfNotFound(N n1, E edge, N n2)` Connects two nodes in the graph with an edge if such edge does not already exists between the nodes.
`abstract GraphNode<N,E>`	`createNode(N value)` Gets a node from the graph given a value.
`abstract void`	`disconnect(N n1, N n2)` Disconnects two nodes in the graph by removing all edges between them.
`abstract List<Graph.GraphEdge<N,E>>`	`getEdges()` Gets an immutable list of all edges.
`abstract List<Graph.GraphEdge<N,E>>`	`getEdges(N n1, N n2)` Retrieves an edge from the graph.
`abstract Graph.GraphEdge<N,E>`	`getFirstEdge(N n1, N n2)` Retrieves any edge from the graph.
`abstract List<GraphNode<N,E>>`	`getNeighborNodes(N value)` Gets the neighboring nodes.
`abstract Iterator<GraphNode<N,E>>`	`getNeighborNodesIterator(N value)`
`abstract int`	`getNodeDegree(N value)` Gets the degree of a node.
`abstract Collection<GraphNode<N,E>>`	`getNodes()` Gets an immutable list of all nodes.
`int`	`getWeight(N value)` Returns a weight for the given value to be used in ordering nodes, e.g.
`boolean`	`hasNode(N n)` Checks whether the node exists in the graph (`createNode(Object)` has been called with that value).
`abstract boolean`	`isConnected(N n1, E e, N n2)` Checks whether two nodes in the graph are connected by the given edge type.
`abstract boolean`	`isConnected(N n1, N n2)` Checks whether two nodes in the graph are connected.
`void`	`popEdgeAnnotations()` Restores edges' annotation values to state before last `pushEdgeAnnotations()`.
`void`	`popNodeAnnotations()` Restores nodes' annotation values to state before last `pushNodeAnnotations()`.
`void`	`pushEdgeAnnotations()` Pushes edges' annotation values.
`void`	`pushNodeAnnotations()` Pushes nodes' annotation values.

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

Methods inherited from interface com.google.javascript.jscomp.graph.AdjacencyGraph
getNode, newSubGraph

- Constructor Detail
  - Graph
```
public Graph()
```
- Method Detail
  - connect
```
public abstract void connect(N n1,
           E edge,
           N n2)
```
    Connects two nodes in the graph with an edge.
    
    Parameters:
    n1 - First node.
    edge - The edge.
    n2 - Second node.
  - disconnect
```
public abstract void disconnect(N n1,
              N n2)
```
    Disconnects two nodes in the graph by removing all edges between them.
    
    Parameters:
    n1 - First node.
    n2 - Second node.
  - connectIfNotFound
```
public final void connectIfNotFound(N n1,
                     E edge,
                     N n2)
```
    Connects two nodes in the graph with an edge if such edge does not already exists between the nodes.
    
    Parameters:
    n1 - First node.
    edge - The edge.
    n2 - Second node.
  - createNode
```
public abstract GraphNode<N,E> createNode(N value)
```
    Gets a node from the graph given a value. New nodes are created if that value has not been assigned a graph node. Values equality are compared using Object.equals.
    
    Parameters:
    value - The node's value.
    
    Returns:
    The corresponding node in the graph.
  - getNodes
```
public abstract Collection<GraphNode<N,E>> getNodes()
```
    Gets an immutable list of all nodes.
    
    Specified by:
    
    getNodes in interface AdjacencyGraph<N,E>
  - getEdges
```
public abstract List<Graph.GraphEdge<N,E>> getEdges()
```
    Gets an immutable list of all edges.
  - getNodeDegree
```
public abstract int getNodeDegree(N value)
```
    Gets the degree of a node.
    
    Parameters:
    value - The node's value.
    
    Returns:
    The degree of the node.
  - getWeight
```
public int getWeight(N value)
```
    Description copied from interface: AdjacencyGraph
    
    Returns a weight for the given value to be used in ordering nodes, e.g. in GraphColoring.
    
    Specified by:
    
    getWeight in interface AdjacencyGraph<N,E>
  - getNeighborNodes
```
public abstract List<GraphNode<N,E>> getNeighborNodes(N value)
```
    Gets the neighboring nodes.
    
    Parameters:
    value - The node's value.
    
    Returns:
    A list of neighboring nodes.
  - getNeighborNodesIterator
```
public abstract Iterator<GraphNode<N,E>> getNeighborNodesIterator(N value)
```
  - getEdges
```
public abstract List<Graph.GraphEdge<N,E>> getEdges(N n1,
                                  N n2)
```
    Retrieves an edge from the graph.
    
    Parameters:
    n1 - Node one.
    n2 - Node two.
    
    Returns:
    The list of edges between those two values in the graph.
  - getFirstEdge
```
public abstract Graph.GraphEdge<N,E> getFirstEdge(N n1,
                                N n2)
```
    Retrieves any edge from the graph.
    
    Parameters:
    n1 - Node one.
    n2 - Node two.
    
    Returns:
    The first edges between those two values in the graph. null if there are none.
  - hasNode
```
public final boolean hasNode(N n)
```
    Checks whether the node exists in the graph (createNode(Object) has been called with that value).
    
    Parameters:
    n - Node.
    
    Returns:
    true if it exist.
  - isConnected
```
public abstract boolean isConnected(N n1,
                  N n2)
```
    Checks whether two nodes in the graph are connected.
    
    Parameters:
    n1 - Node 1.
    n2 - Node 2.
    
    Returns:
    true if the two nodes are connected.
  - isConnected
```
public abstract boolean isConnected(N n1,
                  E e,
                  N n2)
```
    Checks whether two nodes in the graph are connected by the given edge type.
    
    Parameters:
    n1 - Node 1.
    e - The edge type.
    n2 - Node 2.
  - clearNodeAnnotations
```
public final void clearNodeAnnotations()
```
    Description copied from interface: AdjacencyGraph
    
    Makes each node's annotation null.
    
    Specified by:
    
    clearNodeAnnotations in interface AdjacencyGraph<N,E>
  - clearEdgeAnnotations
```
public final void clearEdgeAnnotations()
```
    Makes each edge's annotation null.
  - pushNodeAnnotations
```
public final void pushNodeAnnotations()
```
    Pushes nodes' annotation values. Restored with popNodeAnnotations(). Nodes' annotation values are cleared.
  - popNodeAnnotations
```
public final void popNodeAnnotations()
```
    Restores nodes' annotation values to state before last pushNodeAnnotations().
  - pushEdgeAnnotations
```
public final void pushEdgeAnnotations()
```
    Pushes edges' annotation values. Restored with popEdgeAnnotations(). Edges' annotation values are cleared.
  - popEdgeAnnotations
```
public final void popEdgeAnnotations()
```
    Restores edges' annotation values to state before last pushEdgeAnnotations().

Class Graph<N,E>

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface com.google.javascript.jscomp.graph.AdjacencyGraph

Constructor Detail

Graph

Method Detail

connect

disconnect

connectIfNotFound

createNode

getNodes

getEdges

getNodeDegree

getWeight

getNeighborNodes

getNeighborNodesIterator

getEdges

getFirstEdge

hasNode

isConnected

isConnected

clearNodeAnnotations

clearEdgeAnnotations

pushNodeAnnotations

popNodeAnnotations

pushEdgeAnnotations

popEdgeAnnotations