ESC/Java2
© 2003,2004,2005 David Cok and Joseph Kiniry
© 2005 UCD Dublin
© 2003,2004 Radboud University Nijmegen
© 1999,2000 Compaq Computer Corporation
© 1997,1998,1999 Digital Equipment Corporation
All Rights Reserved

escjava.prover
Class SNil

java.lang.Object
  extended byescjava.prover.SExp
      extended byescjava.prover.SList
          extended byescjava.prover.SNil

final class SNil
extends SList

The single SNil instance represents the empty list of SExps.


Field Summary
private static SNil single
          The single instance of this class, or null if it has not yet been allocated.
 
Constructor Summary
private SNil()
          Instance creation is private so we can ensure that at most one instance of this class is ever created.
 
Method Summary
 boolean equals(java.lang.Object o)
           
static SNil getNil()
           
 boolean isEmpty()
           
 int length()
           
 
Methods inherited from class escjava.prover.SList
addEnd, addFront, append, at, fromArray, getList, getPair, isList, main, make, make, make, make, make, make, make, make, make, prettyPrint, print, reverseD, setAt
 
Methods inherited from class escjava.prover.SExp
display, fancyMake, getAtom, getInteger, isAtom, isInteger, make, print, toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

single

private static SNil single
The single instance of this class, or null if it has not yet been allocated.

Constructor Detail

SNil

private SNil()
Instance creation is private so we can ensure that at most one instance of this class is ever created.

Method Detail

getNil

public static SNil getNil()
Returns:
the single SNil instance.

equals

public boolean equals(java.lang.Object o)
Returns:
true if the parameter is also the single instance of SNil.

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in class SList
Returns:
a flag indicating if we are we an empty list, which is always true since we are the nil instance.

length

public int length()
Specified by:
length in class SList
Returns:
our length, which is zero since we are the nil instance.

ESC/Java2
© 2003,2004,2005 David Cok and Joseph Kiniry
© 2005 UCD Dublin
© 2003,2004 Radboud University Nijmegen
© 1999,2000 Compaq Computer Corporation
© 1997,1998,1999 Digital Equipment Corporation
All Rights Reserved

The ESC/Java2 Project Homepage