io.github.oliviercailloux.jaris.exceptions.TryOptional Maven / Gradle / Ivy
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package io.github.oliviercailloux.jaris.exceptions;
import java.util.Optional;
/**
* The root of the {@code Try*} hierarchy, defining in the most general way the concepts of success,
* failure, and equality.
*
* Is homeomorphic to an {@code Optional} xor {@code X}: either is a success, and then
* may contain a result of type {@code T}, or is a failure, and then does contain
* a cause of type {@code X}.
*
* @param the type of result possibly kept in this object.
* @param the type of cause kept in this object if it is a failure.
*/
public interface TryOptional {
/**
* Returns {@code true} iff this instance represents a success.
*
* @return {@code true} iff {@link #isFailure()} returns {@code false}
*/
public boolean isSuccess();
/**
* Return {@code true} iff this instance contains a cause.
*
* @return {@code true} iff {@link #isSuccess()} returns {@code false}
*/
public boolean isFailure();
/**
* Returns the result contained in this instance. This is necessarily empty if this is a failure,
* and may be non-empty if this is a success.
*
* @return the result contained in this instance as an optional
*/
public Optional getResult();
/**
* Returns the cause contained in this instance.
*
* @return a present optional iff this instance is a failure.
* @see #isFailure()
*/
public Optional getCause();
/**
* Returns {@code true} iff the given object is a {@code TryOptional}, this and the given object
* are both successes and have equal results, or are both failures and have equal causes.
*
* @param o2 the object to compare this instance to
* @return {@code true} iff {@code o2} is a {@code TryOptional} and this instance and {@code o2}
* have equal results (considered as optional) and equal causes (considered as optional)
*/
@Override
public boolean equals(Object o2);
/**
* Returns a string representation of this object, suitable for debug.
*/
@Override
public abstract String toString();
}