BinaryConnector


1   /* BinaryConnector.java */
2   
3   package org.quilt.graph;
4   
5   /** 
6    * A Connector holding two edges. Implementation detail: we assume
7    * that in laying out bytecode the 'else' code appears immediately
8    * after the if but the 'then' code is accessed using a goto.
9    *
10   * @author <a HREF="mailto:jddixon@users.sourceforge.net">Jim Dixon</a>
11   */
12  public class BinaryConnector extends Connector {
13      /** The preferred edge, the 'else' edge. */
14      private Edge edge;
15      /** The other edge, the 'then' edge. */
16      private Edge otherEdge;
17      /** Source of both edges. */
18      private Vertex source = null;
19  
20      private void doSetUp(Edge e, Edge otherE) {
21          if (e == null || otherE == null) {
22              throw new IllegalArgumentException   ("arguments cannot be null");
23          }
24          edge      = e;
25          source    = edge.getSource();
26          otherEdge = otherE;
27          if ( source != otherEdge.getSource() ) {
28              throw new IllegalArgumentException   (
29                  "edges in a BinaryConnector must have the same source");
30          }
31      }
32      public BinaryConnector (Edge e, Edge otherE) {
33          doSetUp(e, otherE);
34      }
35      public BinaryConnector (Connector conn, Edge otherE) {
36          if (conn == null) {
37              throw new IllegalArgumentException  ("connector cannot be null");
38          }
39          doSetUp(conn.getEdge(), otherE);
40      }
41      // INTERFACE CONNECTOR //////////////////////////////////////////
42      /** Get the preferred edge. */
43      public Edge getEdge() {
44          return edge;
45      }
46      /** Get the target of the preferred edge. */
47      public Vertex getTarget() {
48          return edge.getTarget();
49      }
50      /** Change the target of the preferred edge. */
51      public void setTarget (Vertex v) {
52          checkTarget(v);
53          edge.setTarget(v);
54      }
55      public int size () {
56          return 2;
57      }
58      // OTHER METHODS ////////////////////////////////////////////////
59      private void checkTarget (final Vertex target) {
60          if (target == null) {
61              throw new IllegalArgumentException  ("target may not be null");
62          }
63          // DEBUG
64          if (source == null) 
65              System.out.println("BinaryConnector.checkTarget INTERNAL ERROR: "
66                  + " source is null");
67          else if (source.getGraph() == null) 
68                  System.out.println(
69                      "BinaryConnector.checkTarget: source has no graph!");
70          if (target.getGraph() == null) 
71              System.out.println(
72                  "BinaryConnector.checkTarget: target has no graph!");
73          // END
74          if ( target.getGraph() != source.getGraph() ) {
75              throw new IllegalArgumentException  (
76                      "new target must be in same graph");
77          }
78      }
79      /** Get the other edge. */
80      public Edge getOtherEdge() {
81          return otherEdge;
82      }
83      /** Get the target of the other edge */
84      public Vertex getOtherTarget() {
85          return otherEdge.getTarget();
86      }
87      /** Set the target of the other edge. */
88      public void setOtherTarget (Vertex v) {
89          checkTarget(v);
90          otherEdge.setTarget (v);
91      }
92  }
93
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