edu.rice.hj.experimental.api

Class HjExpression

java.lang.Object

edu.rice.hj.experimental.api.HjExpression

public final class HjExpression
extends Object

The HjExpression class provides factory method to create boolean expressions wrapping HjFuture instances. Boolean expressions can contain AND, OR, and NOT clauses. Expressions can also be made to evaluate in strict or short-circuit mode.

Using the short-circuit mode (an expression that does not contain a NOT operation) allows the boolean expression to be evaluated after some of the dependent HjFuture instances have been resolved.

Using the strict mode (an expression that contains at least one NOT operation) enforces the constraint that the boolean expression may only be evaluated safely after all the dependent HjFuture instances have been resolved.

Author:

Shams Imam (shams@rice.edu)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	HjExpression.HjAwaitExpression An HjAwaitExpression represents an expression that can be used as the trigger clauses in asyncWhen() constructs.
static class	HjExpression.HjBooleanExpression The parent class for all boolean expressions.

Method Summary

Modifier and Type	Method and Description
static HjExpression.HjBooleanExpression	and(HjExpression.HjBooleanExpression left, HjExpression.HjBooleanExpression right) Returns an HjExpression.HjBooleanExpression representing an AND expression.
static HjExpression.HjBooleanExpression	and(HjFuture<?>[] futures) Returns an HjExpression.HjBooleanExpression representing an AND expression tree.
static HjExpression.HjBooleanExpression	and(HjFuture<?> left, HjFuture<?> right) Returns an HjExpression.HjBooleanExpression representing an AND expression.
static HjExpression.HjAwaitExpression	awaitExpr(HjExpression.HjBooleanExpression expression) Factory method to create a strict HjExpression.HjAwaitExpression
static HjExpression.HjBooleanExpression	countEqualTo(HjFuture<?>[] futures, int count) Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) == count expression.
static HjExpression.HjBooleanExpression	countGreaterOrEqualTo(HjFuture<?>[] futures, int count) Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) >= count expression.
static HjExpression.HjBooleanExpression	countGreaterThan(HjFuture<?>[] futures, int count) Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) > count expression.
static HjExpression.HjBooleanExpression	countLesserOrEqualTo(HjFuture<?>[] futures, int count) Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) <= count expression.
static HjExpression.HjBooleanExpression	countLesserThan(HjFuture<?>[] futures, int count) Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) < count expression.
static HjExpression.HjBooleanExpression	leaf(HjFuture<?> aFuture) Returns an HjExpression.HjBooleanExpression wrapping an HjFuture instance.
static HjExpression.HjBooleanExpression	not(HjExpression.HjBooleanExpression arg) Returns an HjExpression.HjBooleanExpression representing a NOT expression.
static HjExpression.HjBooleanExpression	not(HjFuture<?> arg) Returns an HjExpression.HjBooleanExpression representing a NOT expression.
static HjExpression.HjBooleanExpression	or(HjExpression.HjBooleanExpression left, HjExpression.HjBooleanExpression right) Returns an HjExpression.HjBooleanExpression representing an OR expression.
static HjExpression.HjBooleanExpression	or(HjFuture<?>[] futures) Returns an HjExpression.HjBooleanExpression representing an OR expression tree.
static HjExpression.HjBooleanExpression	or(HjFuture<?> left, HjFuture<?> right) Returns an HjExpression.HjBooleanExpression representing an OR expression.

Methods inherited from class java.lang.Object

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

Method Detail

awaitExpr

public static HjExpression.HjAwaitExpression awaitExpr(HjExpression.HjBooleanExpression expression)

Factory method to create a strict HjExpression.HjAwaitExpression

Parameters:

expression - The boolean expression to wrap.

Returns:

an HjExpression.HjAwaitExpression strict instance.

and

public static HjExpression.HjBooleanExpression and(HjFuture<?>[] futures)

Returns an HjExpression.HjBooleanExpression representing an AND expression tree.

Parameters:

futures - The HjFuture instances to merge into an AND.

Returns:

an HjExpression.HjBooleanExpression representing an AND expression tree.

and

public static HjExpression.HjBooleanExpression and(HjExpression.HjBooleanExpression left,
                                                   HjExpression.HjBooleanExpression right)

Returns an HjExpression.HjBooleanExpression representing an AND expression.

Parameters:

left - The left sub-expression.

right - The right sub-expression.

Returns:

an HjExpression.HjBooleanExpression representing an AND expression.

leaf

public static HjExpression.HjBooleanExpression leaf(HjFuture<?> aFuture)

Returns an HjExpression.HjBooleanExpression wrapping an HjFuture instance.

Parameters:

aFuture - The HjFuture instance to wrap.

Returns:

an HjExpression.HjBooleanExpression wrapping an HjFuture instance.

or

public static HjExpression.HjBooleanExpression or(HjFuture<?>[] futures)

Returns an HjExpression.HjBooleanExpression representing an OR expression tree.

Parameters:

futures - The HjFuture instances to merge into an OR.

Returns:

an HjExpression.HjBooleanExpression representing an OR expression tree.

or

public static HjExpression.HjBooleanExpression or(HjExpression.HjBooleanExpression left,
                                                  HjExpression.HjBooleanExpression right)

Returns an HjExpression.HjBooleanExpression representing an OR expression.

Parameters:

left - The left sub-expression.

right - The right sub-expression.

Returns:

an HjExpression.HjBooleanExpression representing an OR expression.

and

public static HjExpression.HjBooleanExpression and(HjFuture<?> left,
                                                   HjFuture<?> right)

Returns an HjExpression.HjBooleanExpression representing an AND expression.

Parameters:

left - The left HjFuture instance.

right - The right HjFuture instance.

Returns:

an HjExpression.HjBooleanExpression representing an AND expression.

or

public static HjExpression.HjBooleanExpression or(HjFuture<?> left,
                                                  HjFuture<?> right)

Returns an HjExpression.HjBooleanExpression representing an OR expression.

Parameters:

left - The left HjFuture instance.

right - The right HjFuture instance.

Returns:

an HjExpression.HjBooleanExpression representing an OR expression.

not

public static HjExpression.HjBooleanExpression not(HjFuture<?> arg)

Returns an HjExpression.HjBooleanExpression representing a NOT expression.

Parameters:

arg - The HjFuture instance to negate.

Returns:

an HjExpression.HjBooleanExpression representing a NOT expression.

not

public static HjExpression.HjBooleanExpression not(HjExpression.HjBooleanExpression arg)

Returns an HjExpression.HjBooleanExpression representing a NOT expression.

Parameters:

arg - The sub-expression to negate.

Returns:

an HjExpression.HjBooleanExpression representing a NOT expression.

countEqualTo

public static HjExpression.HjBooleanExpression countEqualTo(HjFuture<?>[] futures,
                                                            int count)

Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) == count expression.

Parameters:

futures - The HjFuture instances involved in the count expression.

count - The target count to compare against

Returns:

an HjExpression.HjBooleanExpression representing a COUNT(futures) == count expression.

countGreaterThan

public static HjExpression.HjBooleanExpression countGreaterThan(HjFuture<?>[] futures,
                                                                int count)

Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) > count expression.

Parameters:

futures - The HjFuture instances involved in the count expression.

count - The target count to compare against

Returns:

an HjExpression.HjBooleanExpression representing a COUNT(futures) > count expression.

countGreaterOrEqualTo

public static HjExpression.HjBooleanExpression countGreaterOrEqualTo(HjFuture<?>[] futures,
                                                                     int count)

Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) >= count expression.

Parameters:

futures - The HjFuture instances involved in the count expression.

count - The target count to compare against

Returns:

an HjExpression.HjBooleanExpression representing a COUNT(futures) >= count expression.

countLesserThan

public static HjExpression.HjBooleanExpression countLesserThan(HjFuture<?>[] futures,
                                                               int count)

Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) < count expression.

Parameters:

futures - The HjFuture instances involved in the count expression.

count - The target count to compare against

Returns:

an HjExpression.HjBooleanExpression representing a COUNT(futures) < count expression.

countLesserOrEqualTo

public static HjExpression.HjBooleanExpression countLesserOrEqualTo(HjFuture<?>[] futures,
                                                                    int count)

Returns an HjExpression.HjBooleanExpression representing a COUNT(futures) <= count expression.

Parameters:

futures - The HjFuture instances involved in the count expression.

count - The target count to compare against

Returns:

an HjExpression.HjBooleanExpression representing a COUNT(futures) <= count expression.