pl.ais.commons.bean.validation.Constraint Maven / Gradle / Ivy
package pl.ais.commons.bean.validation;
import pl.ais.commons.bean.validation.constrainable.Constrainable;
import pl.ais.commons.bean.validation.event.ConstraintViolated;
import pl.ais.commons.bean.validation.event.ValidationListener;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.Arrays;
import java.util.function.BiFunction;
/**
* Defines the API contract for the Constraint.
*
* @param the type of constraint
* @param the type of values supported by the constraint
* @author Warlock, AIS.PL
* @since 1.2.1
*/
public interface Constraint, T> extends BiFunction, ValidationListener, Boolean> {
/**
* Creates and returns composite constraint being conjunction of this and provided constraint.
*
* @param other constraint to be used for building conjunction with this one
* @return constraint being conjunction of this and provided constraint
*/
Constraint and(@Nonnull final Constraint other);
/**
* Verifies if given constrainable matches the constraint and reports violation if needed.
*
* @param constrainable the constrainable to be checked
* @param listener the validation listener observing constraint violations
* @return {@code true} if given constrainable matches the constraint, {@code false} otherwise
*/
@Override
@Nonnull
default Boolean apply(final Constrainable constrainable, final ValidationListener listener) {
final boolean matched = constrainable.apply(this);
if (!matched) {
listener.constraintViolated(new ConstraintViolated(this, constrainable));
}
return matched;
}
/**
* @return the message which should be used to describe this constraint
*/
String getMessage();
/**
* @return the message parameters
*/
Object[] getMessageParameters();
/**
* @return name of this constraint
*/
String getName();
/**
* Negates the name of the constraint by adding/removing 'not' at the beginning of the name.
*
* @return negated constraint name
*/
default String getNegatedName() {
char[] name = getName().toCharArray();
final StringBuilder builder = new StringBuilder();
// ... by cutting off / adding the 'not' prefix, ...
if ((name.length >= 3) && ('n' == name[0]) && ('o' == name[1]) && ('t' == name[2])) {
name = Arrays.copyOfRange(name, 3, name.length);
} else {
builder.append("not");
}
name[0] = Character.toUpperCase(name[0]);
builder.append(name);
return builder.toString();
}
/**
* Indicates if this constraint is active.
*
* @return {@code true} if this constraint is active, {@code false} otherwise
*/
boolean isActive();
/**
* Creates and returns constraint being negation of this one.
*
* @return constraint being negation of this one
*/
Constraint negate();
/**
* Creates and returns composite constraint being disjunction of this one and provided constraint.
*
* @param other constraint to be used for building disjunction with this one
* @return constraint being disjunction of this one and provided constraint
*/
Constraint or(@Nonnull final Constraint other);
/**
* Evaluates this constraint on the given argument.
*
* Note: disabled constraints are matched by any candidates. Use {@link #isActive()} method to
* properly handle this situation.
*
* @param candidate value to be matched against this constraint
* @return {@code true} if given argument matches this constraint, {@code false} otherwise
*/
boolean test(@Nullable T candidate);
/**
* Provides the constraint (de)activating method.
*
* @param active defines if this constraint is active
* @return constraint instance (for method invocation chaining)
*/
@Nonnull
C when(boolean active);
/**
* Provides the message (potentially parametrized) which should be used to describe the constraint.
*
* @param message the message (potentially parametrized)
* @param messageParameters the message parameters (if any)
* @return constraint instance (for method invocation chaining)
*/
@Nonnull
C withDescription(@Nonnull String message, Object... messageParameters);
/**
* Provides the message parameters which should be used to describe the constraint.
*
* @param messageParameters the message parameters (if any)
* @return constraint instance (for method invocation chaining)
*/
@Nonnull
C withMessageParameters(Object... messageParameters);
}