| /* |
| * 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.statefun.sdk.match; |
| |
| import org.apache.flink.statefun.sdk.Context; |
| import org.apache.flink.statefun.sdk.StatefulFunction; |
| |
| /** |
| * A {@link StatefulMatchFunction} is an utility {@link StatefulFunction} that supports pattern |
| * matching on function inputs to decide how the inputs should be processed. |
| * |
| * <p>Please see {@link MatchBinder} for the supported types of pattern matching. |
| * |
| * @see MatchBinder |
| */ |
| public abstract class StatefulMatchFunction implements StatefulFunction { |
| |
| private boolean setup = false; |
| |
| private MatchBinder matcher = new MatchBinder(); |
| |
| /** |
| * Configures the patterns to match for the function's inputs. |
| * |
| * @param binder a {@link MatchBinder} to bind patterns on. |
| */ |
| public abstract void configure(MatchBinder binder); |
| |
| @Override |
| public final void invoke(Context context, Object input) { |
| ensureInitialized(); |
| matcher.invoke(context, input); |
| } |
| |
| private void ensureInitialized() { |
| if (!setup) { |
| setup = true; |
| configure(matcher); |
| } |
| } |
| } |