org.immutables.criteria.matcher.Aggregation Maven / Gradle / Ivy

Go to download
/*
 * Copyright 2019 Immutables Authors and Contributors
 *
 * 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 org.immutables.criteria.matcher;

import org.immutables.criteria.expression.AggregationOperators;
import org.immutables.criteria.expression.Expressions;

public interface Aggregation extends Projection {

  /**
   * Used to provide aggregation template for comparable types ({@link Comparable}).
   * @param  type of min/max value(s). Can be optional type.
   */
  interface ComparableTemplate extends Count, Min, Max {}

  /**
   * Used to provide aggregation template for numeric types (eg. {@link Number}).
   * @param  type of min/max value(s). Can be optional type.
   * @param  type of the sum computation. Can be optional type.
   * @param  type of the average computation. Can be optional type.
   */
  interface NumberTemplate extends Count, ComparableTemplate, Sum, Avg {}

  interface Min {
    default Aggregation min() {
      return Matchers.extract((Matcher) this).applyRaw(e -> Expressions.aggregation(AggregationOperators.MIN, Matchers.aggregationType(getClass(), Min.class, "min", e), e)).createWith(creator());
    }
  }

  interface Max  {
    default Aggregation max() {
      return Matchers.extract((Matcher) this).applyRaw(e -> Expressions.aggregation(AggregationOperators.MAX, Matchers.aggregationType(getClass(), Max.class, "max", e), e)).createWith(creator());
    }
  }

  interface Count  {
    default Aggregation count() {
      return Matchers.extract((Matcher) this).applyRaw(e -> Expressions.aggregation(AggregationOperators.COUNT, Long.class, e)).createWith(creator());
    }
  }

  interface Avg {
    default Aggregation avg() {
      return Matchers.extract((Matcher) this).applyRaw(e -> Expressions.aggregation(AggregationOperators.AVG, Matchers.aggregationType(getClass(), Avg.class, "avg", e), e)).createWith(creator());
    }
  }

  interface Sum {
    default Aggregation sum() {
      return Matchers.extract((Matcher) this).applyRaw(e -> Expressions.aggregation(AggregationOperators.SUM, Matchers.aggregationType(getClass(), Sum.class, "sum", e), e)).createWith(creator());
    }
  }

  @SuppressWarnings("unchecked")
  static  CriteriaCreator creator() {
    class Local extends AbstractContextHolder implements Aggregation, Matcher {
      private Local(CriteriaContext context) {
        super(context);
      }
    }

    return ctx -> (T) new Local(ctx);
  }

}