Solver (OptaPlanner distribution 7.35.0.Final API)

Type Parameters:

Solution_ - the solution type, the class with the PlanningSolution annotation

All Known Implementing Classes:

AbstractSolver, DefaultSolver, PartitionSolver
```
public interface Solver<Solution_>
```
A Solver solves a planning problem and returns the best solution found. It's recommended to create a new Solver instance for each dataset.
To create a Solver, use SolverFactory.buildSolver(). To solve a planning problem, call solve(Object). To solve a planning problem without blocking the current thread, use SolverManager instead.
These methods are not thread-safe and should be called from the same thread, except for the methods that are explicitly marked as thread-safe. Note that despite that solve(Solution_) is not thread-safe for clients of this class, that method is free to do multithreading inside itself.

Method Summary

All Methods Instance Methods Abstract Methods Deprecated Methods
Modifier and Type	Method and Description
`void`	`addEventListener(SolverEventListener<Solution_> eventListener)`
`boolean`	`addProblemFactChange(ProblemFactChange<Solution_> problemFactChange)` Schedules a `ProblemFactChange` to be processed.
`boolean`	`addProblemFactChanges(List<ProblemFactChange<Solution_>> problemFactChangeList)` Schedules multiple `ProblemFactChange`s to be processed.
`String`	`explainBestScore()` Returns a diagnostic text that explains the `getBestSolution()` through the `ConstraintMatch` API to identify which constraints or planning entities cause that `getBestScore()` quality.
`Score`	`getBestScore()` Returns the `Score` of the `getBestSolution()`.
`Solution_`	`getBestSolution()` The best solution is the `best solution` found during solving: it might or might not be optimal, feasible or even initialized.
`ScoreDirectorFactory<Solution_>`	`getScoreDirectorFactory()` Deprecated. in favor of `SolverFactory.getScoreDirectorFactory()` Will be removed in 8.0.
`long`	`getTimeMillisSpent()` Returns the amount of milliseconds spent solving since the last start.
`boolean`	`isEveryProblemFactChangeProcessed()` Checks if all scheduled `ProblemFactChange`s have been processed.
`boolean`	`isSolving()` This method is thread-safe.
`boolean`	`isTerminateEarly()` This method is thread-safe.
`void`	`removeEventListener(SolverEventListener<Solution_> eventListener)`
`Solution_`	`solve(Solution_ problem)` Solves the planning problem and returns the best solution encountered (which might or might not be optimal, feasible or even initialized).
`boolean`	`terminateEarly()` Notifies the solver that it should stop at its earliest convenience.

- Method Detail
  - solve
```
Solution_ solve(Solution_ problem)
```
    Solves the planning problem and returns the best solution encountered (which might or might not be optimal, feasible or even initialized).
    It can take seconds, minutes, even hours or days before this method returns, depending on the Termination configuration. To terminate a Solver early, call terminateEarly().
    
    Parameters:
    
    problem - never null, a PlanningSolution, usually its planning variables are uninitialized
    
    Returns:
    
    never null, but it can return the original, uninitialized PlanningSolution with a null Score.
    
    See Also:
    
    terminateEarly()
  - terminateEarly
```
boolean terminateEarly()
```
    Notifies the solver that it should stop at its earliest convenience. This method returns immediately, but it takes an undetermined time for the solve(Solution_) to actually return.
    If the solver is running in daemon mode, this is the only way to terminate it normally.
    This method is thread-safe. It can only be called from a different thread because the original thread is still calling solve(Object).
    
    Returns:
    
    true if successful, false if was already terminating or terminated
    
    See Also:
    
    isTerminateEarly(), Future.cancel(boolean)
  - getBestSolution
```
Solution_ getBestSolution()
```
    The best solution is the best solution found during solving: it might or might not be optimal, feasible or even initialized.
    The solve(Solution_) method also returns the best solution, but this method is useful in rare asynchronous situations (although SolverEventListener.bestSolutionChanged(BestSolutionChangedEvent) is often more appropriate).
    This method is thread-safe.
    
    Returns:
    
    never null (unless solve(Object) hasn't been called yet), but it can return the uninitialized PlanningSolution with a Score null.
  - getBestScore
```
Score getBestScore()
```
    Returns the Score of the getBestSolution().
    This is useful for generic code, which doesn't know the type of the PlanningSolution to retrieve the Score from the getBestSolution() easily.
    This method is thread-safe.
    
    Returns:
    
    null if the PlanningSolution is still uninitialized
  - explainBestScore
```
String explainBestScore()
```
    Returns a diagnostic text that explains the getBestSolution() through the ConstraintMatch API to identify which constraints or planning entities cause that getBestScore() quality. In case of an infeasible solution, this can help diagnose the cause of that.
    Do not parse this string. Instead, to provide this information in a UI or a service, use SolverFactory.getScoreDirectorFactory() to retrieve ScoreDirector.getConstraintMatchTotalMap() and ScoreDirector.getIndictmentMap() and convert those into a domain specific API.
    This method is thread-safe.
    
    Returns:
    
    null if getBestScore() returns null
    
    See Also:
    
    ScoreDirector.explainScore()
  - getTimeMillisSpent
```
long getTimeMillisSpent()
```
    Returns the amount of milliseconds spent solving since the last start. If it hasn't started it yet, it returns 0. If it hasn't ended yet, it returns the time between the last start and now. If it has ended already, it returns the time between the last start and the ending.
    A addProblemFactChange(ProblemFactChange) triggers a restart which resets this time.
    This method is thread-safe.
    
    Returns:
    
    the amount of milliseconds spent solving since the last (re)start, at least 0
  - isSolving
```
boolean isSolving()
```
    This method is thread-safe.
    
    Returns:
    
    true if the solve(Solution_) method is still running.
  - isTerminateEarly
```
boolean isTerminateEarly()
```
    This method is thread-safe.
    
    Returns:
    
    true if terminateEarly has been called since the Solver started.
    
    See Also:
    
    Future.isCancelled()
  - addProblemFactChange
```
boolean addProblemFactChange(ProblemFactChange<Solution_> problemFactChange)
```
    Schedules a ProblemFactChange to be processed.
    As a side-effect, this restarts the Solver, effectively resetting all Terminations, but not terminateEarly().
    This method is thread-safe. Follows specifications of BlockingQueue.add(Object) with by default a capacity of Integer.MAX_VALUE.
    
    Parameters:
    
    problemFactChange - never null
    
    Returns:
    
    true (as specified by Collection.add(E))
    
    See Also:
    
    addProblemFactChanges(List)
  - addProblemFactChanges
```
boolean addProblemFactChanges(List<ProblemFactChange<Solution_>> problemFactChangeList)
```
    Schedules multiple ProblemFactChanges to be processed.
    As a side-effect, this restarts the Solver, effectively resetting all Terminations, but not terminateEarly().
    This method is thread-safe. Follows specifications of Collection.addAll(Collection) with by default a capacity of Integer.MAX_VALUE.
    
    Parameters:
    
    problemFactChangeList - never null
    
    Returns:
    
    true (as specified by Collection.add(E))
    
    See Also:
    
    addProblemFactChange(ProblemFactChange)
  - isEveryProblemFactChangeProcessed
```
boolean isEveryProblemFactChangeProcessed()
```
    Checks if all scheduled ProblemFactChanges have been processed.
    This method is thread-safe.
    
    Returns:
    
    true if there are no ProblemFactChanges left to do
  - addEventListener
```
void addEventListener(SolverEventListener<Solution_> eventListener)
```
    Parameters:
    
    eventListener - never null
  - removeEventListener
```
void removeEventListener(SolverEventListener<Solution_> eventListener)
```
    Parameters:
    
    eventListener - never null
  - getScoreDirectorFactory
```
@Deprecated
ScoreDirectorFactory<Solution_> getScoreDirectorFactory()
```
    Deprecated. in favor of SolverFactory.getScoreDirectorFactory() Will be removed in 8.0.
    
    Useful to reuse the Score calculation (for example in a UI) and to explain the Score to the user with the ConstraintMatchTotal and Indictment API.
    
    Returns:
    
    never null

Interface Solver<Solution_>

Method Summary

Method Detail

solve

terminateEarly

getBestSolution

getBestScore

explainBestScore

getTimeMillisSpent

isSolving

isTerminateEarly

addProblemFactChange

addProblemFactChanges

isEveryProblemFactChangeProcessed

addEventListener

removeEventListener

getScoreDirectorFactory