/*
* Hibernate Validator, declare and validate application constraints
*
* License: Apache License, Version 2.0
* See the license.txt file in the root directory or <http://www.apache.org/licenses/LICENSE-2.0>.
*/
package org.hibernate.validator.internal.engine;
import java.lang.annotation.Annotation;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.validation.ConstraintValidator;
import com.fasterxml.classmate.ResolvedType;
import org.hibernate.validator.internal.util.TypeResolutionHelper;
import org.hibernate.validator.internal.util.privilegedactions.GetConstraintValidatorList;
import org.hibernate.validator.spi.constraintdefinition.ConstraintDefinitionContributor;
import static org.hibernate.validator.internal.util.CollectionHelper.newHashMap;
/**
* @author Hardy Ferentschik
*/
public class ServiceLoaderBasedConstraintDefinitionContributor implements ConstraintDefinitionContributor {
/**
* Used for resolving type parameters. Thread-safe.
*/
private final TypeResolutionHelper typeResolutionHelper;
public ServiceLoaderBasedConstraintDefinitionContributor(TypeResolutionHelper typeResolutionHelper) {
this.typeResolutionHelper = typeResolutionHelper;
}
@Override
public void collectConstraintDefinitions(ConstraintDefinitionBuilder constraintDefinitionContributionBuilder) {
Map<Class<?>, List<Class<?>>> customValidators = newHashMap();
// find additional constraint validators via the Java ServiceLoader mechanism
GetConstraintValidatorList constraintValidatorListAction = new GetConstraintValidatorList();
List<ConstraintValidator<?, ?>> discoveredConstraintValidators = run( constraintValidatorListAction );
for ( ConstraintValidator<?, ?> constraintValidator : discoveredConstraintValidators ) {
Class<?> constraintValidatorClass = constraintValidator.getClass();
Class<?> annotationType = determineAnnotationType( constraintValidatorClass );
List<Class<?>> validators = customValidators.get( annotationType );
if ( annotationType != null && validators == null ) {
validators = new ArrayList<Class<?>>();
customValidators.put( annotationType, validators );
}
validators.add( constraintValidatorClass );
}
for ( Map.Entry<Class<?>, List<Class<?>>> entry : customValidators.entrySet() ) {
registerConstraintDefinition( constraintDefinitionContributionBuilder, entry.getKey(), entry.getValue() );
}
}
@SuppressWarnings("unchecked")
private <A extends Annotation> void registerConstraintDefinition(ConstraintDefinitionBuilder builder,
Class<?> constraintType,
List<Class<?>> validatorTypes) {
ConstraintDefinitionBuilderContext<A> context = builder
.constraint( (Class<A>) constraintType )
.includeExistingValidators( true );
for ( Class<?> validatorType : validatorTypes ) {
context.validatedBy( (Class<? extends ConstraintValidator<A, ?>>) validatorType );
}
}
private Class<?> determineAnnotationType(Class<?> constraintValidatorClass) {
ResolvedType resolvedType = typeResolutionHelper.getTypeResolver()
.resolve( constraintValidatorClass );
return resolvedType.typeParametersFor( ConstraintValidator.class ).get( 0 ).getErasedType();
}
/**
* Runs the given privileged action, using a privileged block if required.
* <p>
* <b>NOTE:</b> This must never be changed into a publicly available method to avoid execution of arbitrary
* privileged actions within HV's protection domain.
*/
private <T> T run(PrivilegedAction<T> action) {
return System.getSecurityManager() != null ? AccessController.doPrivileged( action ) : action.run();
}
}