File	Doc	Category	Size	Date	Package
terminal_set.java	API Doc	Java SE 5 API	6638	Fri Aug 26 14:54:54 BST 2005	com.sun.java_cup.internal

terminal_set

• java.lang.Object

Fields Summary
public static final terminal_set	EMPTY Constant for the empty set.
protected BitSet	_elements Bitset to implement the actual set.

Constructors Summary
public terminal_set() Constructor for an empty set. /* allocate the bitset at what is probably the right size */ _elements = new BitSet(terminal.number());
public terminal_set(terminal_set other) Constructor for cloning from another set. param other the set we are cloning from. not_null(other); _elements = (BitSet)other._elements.clone();

Methods Summary
public boolean	add(com.sun.java_cup.internal.terminal_set other) Add (union) in a complete set. param other the set being added. return true if this changes the set. not_null(other); /* make a copy */ BitSet copy = (BitSet)_elements.clone(); /* or in the other set */ _elements.or(other._elements); /* changed if we are not the same as the copy */ return !_elements.equals(copy);
public boolean	add(terminal sym) Add a single terminal to the set. param sym the terminal being added. return true if this changes the set. boolean result; not_null(sym); /* see if we already have this */ result = _elements.get(sym.index()); /* if not we add it */ if (!result) _elements.set(sym.index()); return result;
public boolean	contains(terminal sym) Determine if the set contains a particular terminal. param sym the terminal symbol we are looking for. not_null(sym); return _elements.get(sym.index());
public boolean	contains(int indx) Given its index determine if the set contains a particular terminal. param indx the index of the terminal in question. return _elements.get(indx);
public boolean	empty() Determine if the set is empty. return equals(EMPTY);
public boolean	equals(com.sun.java_cup.internal.terminal_set other) Equality comparison. if (other == null) return false; else return _elements.equals(other._elements);
public boolean	equals(java.lang.Object other) Generic equality comparison. if (!(other instanceof terminal_set)) return false; else return equals((terminal_set)other);
public boolean	intersects(com.sun.java_cup.internal.terminal_set other) Determine if this set intersects another. param other the other set in question. not_null(other); /* make a copy of the other set */ BitSet copy = (BitSet)other._elements.clone(); /* xor out our values */ copy.xor(this._elements); /* see if its different */ return !copy.equals(other._elements);
public boolean	is_subset_of(com.sun.java_cup.internal.terminal_set other) Determine if this set is an (improper) subset of another. param other the set we are testing against. not_null(other); /* make a copy of the other set */ BitSet copy_other = (BitSet)other._elements.clone(); /* and or in */ copy_other.or(_elements); /* if it hasn't changed, we were a subset */ return copy_other.equals(other._elements);
public boolean	is_superset_of(com.sun.java_cup.internal.terminal_set other) Determine if this set is an (improper) superset of another. param other the set we are testing against. not_null(other); return other.is_subset_of(this);
protected void	not_null(java.lang.Object obj) Helper function to test for a null object and throw an exception if one is found. param obj the object we are testing. /*-----------------------------------------------------------*/ /*--- General Methods ----------------------------------------*/ /*-----------------------------------------------------------*/ if (obj == null) throw new internal_error("Null object used in set operation");
public void	remove(terminal sym) Remove a terminal if it is in the set. param sym the terminal being removed. not_null(sym); _elements.clear(sym.index());
public java.lang.String	toString() Convert to string. String result; boolean comma_flag; result = "{"; comma_flag = false; for (int t = 0; t < terminal.number(); t++) { if (_elements.get(t)) { if (comma_flag) result += ", "; else comma_flag = true; result += terminal.find(t).name(); } } result += "}"; return result;