com.bigdata.bop

Interface IBindingSet

All Superinterfaces:

Cloneable, Serializable

All Known Implementing Classes:

ContextBindingSet, EmptyBindingSet, HashBindingSet, ListBindingSet

public interface IBindingSet
extends Cloneable, Serializable

Interface for a set of bindings. The set of variables values is extensible and the bound values are loosely typed.

Version:

$Id$

Author:

Bryan Thompson

Method Summary

Methods

Modifier and Type	Method and Description
void	clear(IVariable var) Clear any binding for the variable.
void	clearAll() Clear all bindings.
IBindingSet	clone() Return a shallow copy of the binding set.
boolean	containsErrorValues()
IBindingSet	copy(IVariable[] variablesToKeep) Return a shallow copy of the binding set, eliminating unnecessary variables.
IBindingSet	copyMinusErrors(IVariable[] variablesToKeep) Return a shallow copy of the binding set, eliminating unnecessary variables and error values (equal to Constant.errorValueConstant()).
boolean	equals(Object o) True iff the variables and their bound values are the same for the two binding sets.
IConstant	get(IVariable var) Return the binding for the variable.
int	hashCode() The hash code of a binding is defined as the bit-wise XOR of the hash codes of the IConstants for its bound variables.
boolean	isBound(IVariable var) Return true iff the variable is bound.
boolean	isEmpty() true iff there are no variable bindings in the binding set.
Iterator<Map.Entry<IVariable,IConstant>>	iterator() Visits the bindings.
void	set(IVariable var, IConstant val) Bind the variable to the value.
int	size() The #of bound variables.
Iterator<IVariable>	vars() Visits the bound variables.

Method Detail

isBound

boolean isBound(IVariable var)

Return true iff the variable is bound.

Parameters:

var - The variable.

Returns:

true if the variable is bound.

Throws:

IllegalArgumentException - if var is null.

set

void set(IVariable var,
       IConstant val)

Bind the variable to the value.

Parameters:

var - The variable.

val - The value (MAY NOT be null).

Throws:

IllegalArgumentException - if var is null.

IllegalArgumentException - if val is null.

get

IConstant get(IVariable var)

Return the binding for the variable.

Parameters:

var - The variable.

Returns:

the binding for the variable -or- null iff the variable is not bound.

Throws:

IllegalArgumentException - if var is null.

clear

void clear(IVariable var)

Clear any binding for the variable.

Parameters:

var - The variable.

Throws:

IllegalArgumentException - if var is null.

clearAll

void clearAll()

Clear all bindings.

isEmpty

boolean isEmpty()

true iff there are no variable bindings in the binding set.

size

int size()

The #of bound variables.

iterator

Iterator<Map.Entry<IVariable,IConstant>> iterator()

Visits the bindings.

vars

Iterator<IVariable> vars()

Visits the bound variables.

clone

IBindingSet clone()

Return a shallow copy of the binding set.

copy

IBindingSet copy(IVariable[] variablesToKeep)

Return a shallow copy of the binding set, eliminating unnecessary variables.

Parameters:

variablesToKeep - When non-null, only the listed variables are retained.

copyMinusErrors

IBindingSet copyMinusErrors(IVariable[] variablesToKeep)

Return a shallow copy of the binding set, eliminating unnecessary variables and error values (equal to Constant.errorValueConstant()).

Parameters:

variablesToKeep - When non-null, only the listed variables are retained.

containsErrorValues

boolean containsErrorValues()

Returns:

true if this IBindingSet contains an assignment of an error value

equals

boolean equals(Object o)

True iff the variables and their bound values are the same for the two binding sets.

Overrides:

equals in class Object

Parameters:

o - Another binding set.

hashCode

int hashCode()

The hash code of a binding is defined as the bit-wise XOR of the hash codes of the IConstants for its bound variables. Unbound variables are ignored when computing the hash code. Binding sets are unordered collections, therefore the calculated hash code intentionally does not depend on the order in which the bindings are visited. The hash code reflects the current state of the bindings and must be recomputed if the bindings are changed.

Overrides:

hashCode in class Object