/**
*
* Copyright (c) 2006-2017, Speedment, Inc. 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.
*/
package com.speedment.plugins.json;
import com.speedment.plugins.json.internal.JsonCollectorImpl;
import java.util.List;
import static java.util.Objects.requireNonNull;
import java.util.stream.Collector;
import static java.util.stream.Collectors.joining;
/**
* A specialized java {@link Collector} that converts streams of Speedment
* entities into JSON arrays.
* <p>
* Example usage:
* <code>
* app.getOrThrow(EmployeeManager.class).stream()
* .filter(Employee.AGE.greaterThan(35))
* .filter(Employee.NAME.startsWith("B"))
* .collect(JsonCollector.toJson(
* jsonComponent.allOf(employees)
* ));
* </code>
*
* @param <ENTITY> the entity type
*
* @author Emil Forslund
* @since 1.0.0
*/
public interface JsonCollector<ENTITY> extends Collector<ENTITY, List<String>, String> {
/**
* Returns a collector that calls the specified encoder for each element in
* the stream and joins the resuling stream separated by commas and
* surrounded by square brackets. Each element is also formatted using the
* specified {@link JsonEncoder}.
*
* @param <ENTITY> the type of the stream
* @param encoder the enocder to use
* @return the json string
*/
static <ENTITY> JsonCollector<ENTITY> toJson(JsonEncoder<ENTITY> encoder) {
requireNonNull(encoder);
return JsonCollectorImpl.collect(
encoder::apply, l -> "[" + l.stream().collect(joining(",")) + "]"
);
}
}