java_cup

Class terminal_set

java.lang.Object

java_cup.terminal_set

public class terminal_set
extends Object

A set of terminals implemented as a bitset.

Version:

last updated: 11/25/95

Author:

Scott Hudson

Field Summary

Fields

Modifier and Type	Field and Description
protected BitSet	_elements Bitset to implement the actual set.
static terminal_set	EMPTY Constant for the empty set.

Constructor Summary

Constructors

Constructor and Description
terminal_set() Constructor for an empty set.
terminal_set(terminal_set other) Constructor for cloning from another set.

Method Summary

Modifier and Type	Method and Description
boolean	add(terminal_set other) Add (union) in a complete set.
boolean	add(terminal sym) Add a single terminal to the set.
boolean	contains(int indx) Given its index determine if the set contains a particular terminal.
boolean	contains(terminal sym) Determine if the set contains a particular terminal.
boolean	empty() Determine if the set is empty.
boolean	equals(Object other) Generic equality comparison.
boolean	equals(terminal_set other) Equality comparison.
boolean	intersects(terminal_set other) Determine if this set intersects another.
boolean	is_subset_of(terminal_set other) Determine if this set is an (improper) subset of another.
boolean	is_superset_of(terminal_set other) Determine if this set is an (improper) superset of another.
protected void	not_null(Object obj) Helper function to test for a null object and throw an exception if one is found.
void	remove(terminal sym) Remove a terminal if it is in the set.
String	toString() Convert to string.

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY

public static final terminal_set EMPTY

Constant for the empty set.

_elements

protected BitSet _elements

Bitset to implement the actual set.

Constructor Detail

terminal_set

public terminal_set()

Constructor for an empty set.

terminal_set

public terminal_set(terminal_set other)
             throws internal_error

Constructor for cloning from another set.

Parameters:

other - the set we are cloning from.

Throws:

internal_error

Method Detail

not_null

protected void not_null(Object obj)
                 throws internal_error

Helper function to test for a null object and throw an exception if one is found.

Parameters:

obj - the object we are testing.

Throws:

internal_error

empty

public boolean empty()

Determine if the set is empty.

contains

public boolean contains(terminal sym)
                 throws internal_error

Determine if the set contains a particular terminal.

Parameters:

sym - the terminal symbol we are looking for.

Throws:

internal_error

contains

public boolean contains(int indx)

Given its index determine if the set contains a particular terminal.

Parameters:

indx - the index of the terminal in question.

is_subset_of

public boolean is_subset_of(terminal_set other)
                     throws internal_error

Determine if this set is an (improper) subset of another.

Parameters:

other - the set we are testing against.

Throws:

internal_error

is_superset_of

public boolean is_superset_of(terminal_set other)
                       throws internal_error

Determine if this set is an (improper) superset of another.

Parameters:

other - the set we are testing against.

Throws:

internal_error

add

public boolean add(terminal sym)
            throws internal_error

Add a single terminal to the set.

Parameters:

sym - the terminal being added.

Returns:

true if this changes the set.

Throws:

internal_error

remove

public void remove(terminal sym)
            throws internal_error

Remove a terminal if it is in the set.

Parameters:

sym - the terminal being removed.

Throws:

internal_error

add

public boolean add(terminal_set other)
            throws internal_error

Add (union) in a complete set.

Parameters:

other - the set being added.

Returns:

true if this changes the set.

Throws:

internal_error

intersects

public boolean intersects(terminal_set other)
                   throws internal_error

Determine if this set intersects another.

Parameters:

other - the other set in question.

Throws:

internal_error

equals

public boolean equals(terminal_set other)

Equality comparison.

equals

public boolean equals(Object other)

Generic equality comparison.

Overrides:

equals in class Object

toString

public String toString()

Convert to string.

Overrides:

toString in class Object