flink-libraries/flink-cep/src/main/java/org/apache/flink/cep/pattern/conditions/RichIterativeCondition.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.cep.pattern.conditions;

import org.apache.flink.api.common.functions.IterationRuntimeContext;
import org.apache.flink.api.common.functions.RichFunction;
import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.cep.CepRuntimeContext;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.util.Preconditions;

/**
 * Rich variant of the {@link IterativeCondition}. As a {@link RichFunction}, it gives access to the
 * {@link org.apache.flink.api.common.functions.RuntimeContext} and provides setup and teardown methods:
 * {@link RichFunction#open(org.apache.flink.configuration.Configuration)} and
 * {@link RichFunction#close()}.
 */
public abstract class RichIterativeCondition<T>
		extends IterativeCondition<T>
		implements RichFunction {

	private static final long serialVersionUID = 1L;

	// --------------------------------------------------------------------------------------------
	//  Runtime context access
	// --------------------------------------------------------------------------------------------

	private transient RuntimeContext runtimeContext;

	@Override
	public void setRuntimeContext(RuntimeContext runtimeContext) {
		Preconditions.checkNotNull(runtimeContext);

		if (runtimeContext instanceof CepRuntimeContext) {
			this.runtimeContext = runtimeContext;
		} else {
			this.runtimeContext = new CepRuntimeContext(runtimeContext);
		}
	}

	@Override
	public RuntimeContext getRuntimeContext() {
		if (this.runtimeContext != null) {
			return this.runtimeContext;
		} else {
			throw new IllegalStateException("The runtime context has not been initialized.");
		}
	}

	@Override
	public IterationRuntimeContext getIterationRuntimeContext() {
		throw new UnsupportedOperationException("Not support to get the IterationRuntimeContext in IterativeCondition.");
	}

	// --------------------------------------------------------------------------------------------
	//  Default life cycle methods
	// --------------------------------------------------------------------------------------------

	@Override
	public void open(Configuration parameters) throws Exception {}

	@Override
	public void close() throws Exception {}

}