Docjar: engine/ConnectionDescription.java

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Source code: engine/ConnectionDescription.java

1   
2   /* **********************************
3    File:ConnectionDescription.java
4    Author: Alec(panovici@elcom.pub.ro)
5    Created on Mon Jul 19 08:13:29 EEST 1999
6    Comments: Part of the vIDE Project
7               Copyright 1999 the vIDE Team.
8   ***********************************/
9   
10  package engine;
11  
12  import middle.*;
13  import java.util.*;
14  
15  /**
16   * A connection from inside a module to the outside world.
17   * It may contain a selection of ports bundled together under a 
18   * single name visible from outside or an expression to be assigned to
19   * the port designated by the name (in a named parameter list).
20   */
21  
22  class ConnectionDescription extends Symbol{
23  
24    /**
25     * The in/out/both type of the connection
26     */
27    int type;
28  
29    /**
30     * The ports bundled inside this name
31     */
32    ExpressionDescription portExpDesc;
33  
34    boolean preparedForContSelection;
35  
36    ConnectionDescription(String name, int lineNo,
37                           ExpressionDescription portExpDesc){
38      super(name, lineNo);
39      this.portExpDesc = portExpDesc;
40    }
41  
42    /**
43     * If this expression is a port selection, computes the overall type:
44     *     if all ports have tha same type with the exception of the inuout ones,
45     *        the overall type is the same. If all the ports are inout, the
46     *        overall is inout.
47     * Note that the if a port identifier is from another module (a fqn with more
48     * than one node), a parse exception is thrown
49     *     else, an exception is thrown
50     */
51    int computeType(DefaultNameSpaceDescription nsd) throws ParseException {
52       // verifies that all the ports have comaptible types
53      PortDescription pd;
54      try{
55        GenericSelectorDescription gsd = (GenericSelectorDescription) portExpDesc;
56        if((pd = nsd.isPort((String) gsd.fqn.node)) != null)
57          return type = pd.type;
58        throw new ParseException (":error : bad port expression : \"" +
59                                  gsd.fqn + "\" is not a port");
60      } catch (ClassCastException cex) {}
61      try {
62        for(Enumeration e =
63              ((SelectionExpressionDescription)portExpDesc).elements() ;
64            e.hasMoreElements() ; )
65        {
66          GenericSelectorDescription ck =
67            (GenericSelectorDescription)e.nextElement();
68          if((pd = nsd.isPort((String) ck.fqn.node)) != null){
69            if(type == PortDescription.none)type = pd.type;
70            else
71              if(!((pd.type == type) ||
72                   (pd.type == PortDescription.inout) ||
73                   (type == PortDescription.inout)))
74                throw new ParseException(":error : bad port expression : \"" +
75                                         pd.name
76                                         + "\" and \"" + name +
77                                         "\" types do not match");
78          }else
79            throw new ParseException(nsd.toString(lineNo) +
80                                     ":error : bad port expression : \"" +
81                                     pd.name + "\" is not a port");
82        }
83      } catch (ClassCastException cex) {
84        throw new ParseException( ":error: bad port expression : not a port selection");
85      }
86      return type;
87    }
88  
89    Object instantiate(NameSpace ns, ScopeNode thisScope)throws ParseException{
90      Expression exp;
91  
92      if (portExpDesc == null) { //fake connection ?
93        type = PortDescription.inout;
94        return null;
95      }
96  
97      try{
98         exp = portExpDesc.instantiate(ns);
99      }catch(ParseException ex){
100       xConsole.dumpStack(ex);
101       throw new ParseException(ns.desc.toString(lineNo) + ex);
102     }
103  
104     return exp;
105   }
106 
107   /**
108    * Makes this expression a continuous expression
109    */
110   void prepareForContSelection()throws ParseException{
111     if(preparedForContSelection)return;
112     preparedForContSelection = true;
113     try{
114       ((AssignableSelection)portExpDesc).toContSelection();
115     }catch(ClassCastException ex){
116       throw new ParseException(" error: \"" + name +
117                                "\" cannot be input");
118     }
119   }
120 
121   public int getType(){
122     return connType;
123   }
124 }
125 
126 
127