fm.pattern.tokamak.server.validation.UniqueValueValidator.java Source code

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Here is the source code for fm.pattern.tokamak.server.validation.UniqueValueValidator.java

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/*
 * Copyright 2012-2017 the original author or authors.
 *
 * 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.
 */

package fm.pattern.tokamak.server.validation;

import static org.apache.commons.lang3.StringUtils.isBlank;

import javax.persistence.Entity;
import javax.persistence.Query;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

import com.google.common.base.CaseFormat;

import fm.pattern.minimal.Reflection;
import fm.pattern.tokamak.server.model.PersistentEntity;
import fm.pattern.tokamak.server.repository.DataRepository;
import fm.pattern.valex.ValidatorSupport;

@Component
public class UniqueValueValidator extends ValidatorSupport
        implements ConstraintValidator<UniqueValue, PersistentEntity> {

    private String property;
    private final DataRepository repository;

    @Autowired
    public UniqueValueValidator(@Qualifier("transactionalDataRepository") DataRepository repository) {
        this.repository = repository;
    }

    public void initialize(UniqueValue annotation) {
        this.property = annotation.property();
    }

    public boolean isValid(PersistentEntity entity, ConstraintValidatorContext constraint) {
        final String value = (String) Reflection.get(entity, property);
        if (isBlank(value)) {
            return true;
        }

        String columnName = CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, property);

        String query = "select count(id) from " + getTableName(entity) + " where " + columnName
                + " = :value and id != :id";
        Query q = repository.query(query).setParameter("value", value).setParameter("id", entity.getId());

        return repository.count(q) == 0;
    }

    private String getTableName(PersistentEntity entity) {
        if (entity.getClass().isAnnotationPresent(Entity.class)) {
            Entity annotation = entity.getClass().getAnnotation(Entity.class);
            return annotation.name();
        }
        throw new IllegalStateException(entity.getClass().getSimpleName()
                + " must have an @Entity annotation configured with the entity name.");
    }

}