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/*-
* ============LICENSE_START=======================================================
* ONAP
* ================================================================================
* Copyright (C) 2020-2021 AT&T Intellectual Property. All rights reserved.
* ================================================================================
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ============LICENSE_END=========================================================
*/
package org.onap.policy.common.parameters;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.List;
import lombok.AccessLevel;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import org.onap.policy.common.parameters.annotations.NotNull;
/**
* Validator of a value.
* <p/>
* Note: this currently does not support Min/Max validation of "short" or "byte"; these
* annotations are simply ignored for these types.
*/
@NoArgsConstructor
public class ValueValidator {
/**
* {@code True} if the value is allowed to be {@code null}, {@code false} otherwise.
* Subclasses are expected to set this, typically based on the validation annotations
* associated with the value.
*/
@Getter
@Setter(AccessLevel.PROTECTED)
private boolean nullAllowed = true;
/**
* Predicates to invoke to validate an object.
* <p/>
* Note: each predicate is expected to return {@code true} if the next check is
* allowed to proceed, {@code false} otherwise. In addition, if {@link #nullAllowed}
* is {@code true}, then the predicates must be prepared to deal with a {@code null}
* Object as their input parameter.
*/
protected List<Checker> checkers = new ArrayList<>(10);
/**
* Determines if the validator has anything to check.
*
* @return {@code true} if the validator is empty (i.e., has nothing to check)
*/
public boolean isEmpty() {
return checkers.isEmpty();
}
/**
* Performs validation of a single field.
*
* @param result validation results are added here
* @param fieldName field whose value is being verified
* @param value value to be validated
*/
protected void validateValue(BeanValidationResult result, String fieldName, Object value) {
if (value == null && isNullAllowed()) {
// value is null and null is allowed - just return
return;
}
for (Checker checker : checkers) {
if (!checker.test(result, fieldName, value)) {
// invalid - don't bother with additional checks
return;
}
}
}
/**
* Looks for an annotation at the class or field level. If an annotation is found at
* either the field or class level, then it adds a verifier to
* {@link ValueValidator#checkers}.
*
* @param annotClass class of annotation to find
* @param checker function to validate the value
*/
public <T extends Annotation> void addAnnotation(Class<T> annotClass, Checker checker) {
var annot = getAnnotation(annotClass);
if (annot != null) {
checkers.add(checker);
if (annotClass == NotNull.class) {
setNullAllowed(false);
}
}
}
/**
* Looks for an annotation at the class or field level. If an annotation is found at
* either the field or class level, then it adds a verifier to
* {@link ValueValidator#checkers}.
*
* @param annotClass class of annotation to find
* @param checker function to validate the value
*/
public <T extends Annotation> void addAnnotation(Class<T> annotClass, CheckerWithAnnot<T> checker) {
var annot = getAnnotation(annotClass);
if (annot != null) {
checkers.add((result, fieldName, value) -> checker.test(result, fieldName, annot, value));
}
}
/**
* Gets an annotation from the field or the class. The default method simply returns
* {@code null}.
*
* @param annotClass annotation class of interest
* @return the annotation, or {@code null} if neither the field nor the class has the
* desired annotation
*/
public <T extends Annotation> T getAnnotation(Class<T> annotClass) {
return null;
}
// functions to validate a value extracted from a field
public static interface Checker {
boolean test(BeanValidationResult result, String fieldName, Object value);
}
public static interface CheckerWithAnnot<T extends Annotation> {
boolean test(BeanValidationResult result, String fieldName, T annotation, Object value);
}
}
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