stormy.pythian.core.description.ReferencedStateDescriptionFactory.java Source code

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Here is the source code for stormy.pythian.core.description.ReferencedStateDescriptionFactory.java

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/**
 * Copyright 2013-2015 Pierre Merienne
 *
 * 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 stormy.pythian.core.description;

import static org.reflections.ReflectionUtils.getFields;
import static org.reflections.ReflectionUtils.withAnnotation;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import org.springframework.stereotype.Component;

import storm.trident.state.StateFactory;
import stormy.pythian.model.annotation.State;

@Component
public class ReferencedStateDescriptionFactory {

    @SuppressWarnings("unchecked")
    public List<ReferencedStateDescription> createDescriptions(Class<?> componentClass) {
        List<ReferencedStateDescription> descriptions = new ArrayList<>();

        Set<Field> fields = getFields(componentClass, withAnnotation(State.class));

        for (Field field : fields) {
            checkSupportedType(field);

            State annotation = field.getAnnotation(State.class);

            ReferencedStateDescription description = new ReferencedStateDescription(annotation.name(),
                    annotation.description());
            descriptions.add(description);
        }

        return descriptions;
    }

    private void checkSupportedType(Field field) {
        Class<?> type = field.getType();
        if (!StateFactory.class.equals(type)) {
            throw new IllegalArgumentException(
                    State.class + " annotation must be used on a " + StateFactory.class + " class");
        }
    }

}