Package net.groboclown.retval

Interface ProblemContainer

All Known Subinterfaces:

RetNullable<T>, RetVal<T>, RetVoid, ValuedProblemContainer<T>

All Known Implementing Classes:

MonitoredReturnProblem, MonitoredReturnValue, MonitoredRetVoidOk, ProblemCollector, SimpleReturnProblem, SimpleReturnValue, SimpleRetVoidOk, ValueAccumulator, ValueBuilder, WarningVal

public interface ProblemContainer

An object that contains problems.

Some implementations may be immutable, while others aren't.

The API intentionally does not accept a generic problem container in many parts of the code as a way to push problems into other objects. Due to the checking mechanisms, care must be taken that values are not incorrectly lost.

Method Summary

Modifier and Type	Method	Description
java.util.Collection<Problem>	anyProblems()	Return all the problems in this object, even if the container is "ok".
java.lang.String	debugProblems(java.lang.String joinedWith)	Return the problems as a single string, which combines the Object.toString() output of each problem with the given joining string parameter.
boolean	hasProblems()	Returns whether this object contains 1 or more problems.
boolean	isOk()	Returns whether this object contains zero problems.
boolean	isProblem()	Returns whether this object contains 1 or more problems.
void	joinProblemsWith(java.util.Collection<Problem> problemList)	Add all problems in this container into the argument.
java.util.Collection<Problem>	validProblems()	Returns all contained problems in this object, but only if this object contains 1 or more problems.

Method Detail

isProblem

boolean isProblem()

Returns whether this object contains 1 or more problems.

Returns:

true if there is a problem, false if there is no problem.

hasProblems

boolean hasProblems()

Returns whether this object contains 1 or more problems. Duplicate of isProblem() for English readability.

Returns:

true if there is a problem, false if there is no problem.

isOk

boolean isOk()

Returns whether this object contains zero problems.

Returns:

true if there are no problems, false if there is a problem.

anyProblems

@Nonnull
java.util.Collection<Problem> anyProblems()

Return all the problems in this object, even if the container is "ok".

Generally, this combines the problems in this instance with a larger collection, which can itself be used to check if any of the values had problems.

The returned collection is read-only, and contains no null values.

Returns:

the problems contained in this container, even if there are none.

validProblems

@Nonnull
java.util.Collection<Problem> validProblems()

Returns all contained problems in this object, but only if this object contains 1 or more problems. If it contains 0, then this throws an IllegalStateException.

The returned collection is read-only, and contains no null values.

Returns:

the problems in this container, and the collection will contain at least 1 item.

Throws:

java.lang.IllegalStateException - if this object has 0 problems.

debugProblems

@Nonnull
java.lang.String debugProblems(@Nonnull
                               java.lang.String joinedWith)

Return the problems as a single string, which combines the Object.toString() output of each problem with the given joining string parameter. If this object contains no problems, then an empty string is returned instead.

Parameters:

joinedWith - the text to join multiple problem strings together.

Returns:

the combined text of the problems, or an empty string if there are no problems.

joinProblemsWith

void joinProblemsWith(@Nonnull
                      java.util.Collection<Problem> problemList)

Add all problems in this container into the argument. This has a very specific usage to indicate that this container, even if it has no problems, is part of a bigger issue. Therefore, this is fine to call even if there are no problems in this container.

Parameters:

problemList - a modifiable collection of zero or more problems.