net.fortytwo.stream.caching

Class SolutionPattern

java.lang.Object

net.fortytwo.stream.caching.SolutionPattern

Direct Known Subclasses:

Solution

public class SolutionPattern
extends Object

An object representing the subset of tuple patterns of a query which have already been matched. A solution pattern is a solution omitting the bindings (which may be stored in a solution group).

Author:

Joshua Shinavier (http://fortytwo.net)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SolutionPattern.ContainmentRelation A relationship between two solution patterns which affects how they may be composed into new solutions.

Field Summary

Fields

Modifier and Type	Field and Description
protected long	expirationTime
protected int	matchedPatterns
protected int	remainingPatterns

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SolutionPattern(int remainingPatterns, int matchedPatterns, long expirationTime)
	SolutionPattern(SolutionPattern other) Copy constructor

Method Summary

Modifier and Type	Method and Description
static int	compareExpirationTimes(SolutionPattern s1, SolutionPattern s2) Compares the expiration times of two solutions
void	copyFrom(SolutionPattern other) Overwrites the fields of this solution with those of a given solution.
boolean	disjointWith(SolutionPattern other) Finds whether this solution is disjoint with another solution
boolean	isComplete() Finds whether this solution is complete
boolean	isExpired(long now) Gets the expiration status of this solution
static long	minExpirationTime(SolutionPattern s1, SolutionPattern s2) Composes the expiration times of two inputs to produce an expiration time for an output.
SolutionPattern.ContainmentRelation	relateTo(SolutionPattern other) Finds the containment relation between this solution and another solution
void	setExpirationTime(long expirationTime) Sets a new expiration time for this solution

Methods inherited from class java.lang.Object

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

Field Detail

remainingPatterns

protected int remainingPatterns

matchedPatterns

protected int matchedPatterns

expirationTime

protected long expirationTime

Constructor Detail

SolutionPattern

protected SolutionPattern(int remainingPatterns,
                          int matchedPatterns,
                          long expirationTime)

SolutionPattern

public SolutionPattern(SolutionPattern other)

Copy constructor

Parameters:

other - another solution pattern to copy

Method Detail

copyFrom

public void copyFrom(SolutionPattern other)

Overwrites the fields of this solution with those of a given solution. An alternative to the copy constructor which does not create a new object.

Parameters:

other - another solution pattern to copy

setExpirationTime

public void setExpirationTime(long expirationTime)

Sets a new expiration time for this solution

Parameters:

expirationTime - an expiration time, in milliseconds since the Unix epoch. The special value 0 indicates that the solution is valid indefinitely.

isExpired

public boolean isExpired(long now)

Gets the expiration status of this solution

Parameters:

now - the current time, in millseconds since the Unix epoch

Returns:

whether this solution has expired, i.e. is no longer valid, with respect to the current time

isComplete

public boolean isComplete()

Finds whether this solution is complete

Returns:

whether this solution is complete. A solution is complete if all tuple patterns in the query have been matched.

disjointWith

public boolean disjointWith(SolutionPattern other)

Finds whether this solution is disjoint with another solution

Parameters:

other - another solution

Returns:

whether this solution is disjoint with the given solution, in terms of matched tuple patterns

relateTo

public SolutionPattern.ContainmentRelation relateTo(SolutionPattern other)

Finds the containment relation between this solution and another solution

Parameters:

other - another solution for comparison

Returns:

the containment relation between this solution and the given solution

minExpirationTime

public static long minExpirationTime(SolutionPattern s1,
                                     SolutionPattern s2)

Composes the expiration times of two inputs to produce an expiration time for an output. The output expires as soon as possible given the expiration times of the two inputs.

Parameters:

s1 - a solution pattern

s2 - a solution pattern

Returns:

the resulting minimum expiration time

compareExpirationTimes

public static int compareExpirationTimes(SolutionPattern s1,
                                         SolutionPattern s2)

Compares the expiration times of two solutions

Parameters:

s1 - a solution pattern

s2 - a solution pattern

Returns:

a comparison value relating the expiration times of the two solutions: -1 if the first solution expires before the second, 1 if the first solution expires after the second, and 0 if the solutions expire at the same time. The infinite expiration time (represented by 0) exceeds all finite expiration times, but is equal to itself.