flink-libraries/flink-sql-client/src/main/java/org/apache/flink/table/client/gateway/TypedResult.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.table.client.gateway;

import java.util.Objects;

/**
 * Result with an attached type (actual payload, EOS, etc.).
 *
 * @param <P> type of payload
 */
public class TypedResult<P> {

	private ResultType type;

	private P payload;

	private TypedResult(ResultType type, P payload) {
		this.type = type;
		this.payload = payload;
	}

	public void setType(ResultType type) {
		this.type = type;
	}

	public void setPayload(P payload) {
		this.payload = payload;
	}

	public ResultType getType() {
		return type;
	}

	public P getPayload() {
		return payload;
	}

	@Override
	public String toString() {
		return "TypedResult<" + type + ">";
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) {
			return true;
		}
		if (o == null || getClass() != o.getClass()) {
			return false;
		}
		TypedResult<?> that = (TypedResult<?>) o;
		return type == that.type && Objects.equals(payload, that.payload);
	}

	@Override
	public int hashCode() {
		return Objects.hash(type, payload);
	}

	// --------------------------------------------------------------------------------------------

	public static <T> TypedResult<T> empty() {
		return new TypedResult<>(ResultType.EMPTY, null);
	}

	public static <T> TypedResult<T> payload(T payload) {
		return new TypedResult<>(ResultType.PAYLOAD, payload);
	}

	public static <T> TypedResult<T> endOfStream() {
		return new TypedResult<>(ResultType.EOS, null);
	}

	// --------------------------------------------------------------------------------------------

	/**
	 * Result types.
	 */
	public enum ResultType {
		PAYLOAD,
		EMPTY,
		EOS
	}
}