| /* |
| * 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.flink.core.protorouter; |
| |
| import com.google.protobuf.Descriptors; |
| import com.google.protobuf.Message; |
| import java.util.List; |
| import java.util.function.Function; |
| import org.apache.flink.statefun.flink.common.protopath.ProtobufPath; |
| |
| final class TemplateEvaluator { |
| |
| private interface FragmentEvaluator { |
| void eval(StringBuilder builder, Message message); |
| } |
| |
| private final FragmentEvaluator[] fragmentEvaluators; |
| private final StringBuilder builder = new StringBuilder(); |
| |
| TemplateEvaluator( |
| Descriptors.Descriptor descriptor, List<TemplateParser.TextFragment> fragments) { |
| this.fragmentEvaluators = fragmentEvaluators(descriptor, fragments); |
| } |
| |
| public String evaluate(Message message) { |
| for (FragmentEvaluator e : fragmentEvaluators) { |
| e.eval(builder, message); |
| } |
| final String result = builder.toString(); |
| builder.delete(0, builder.length()); |
| return result; |
| } |
| |
| private static FragmentEvaluator[] fragmentEvaluators( |
| Descriptors.Descriptor descriptor, List<TemplateParser.TextFragment> fragments) { |
| return fragments.stream() |
| .map( |
| fragment -> |
| fragment.dynamic() |
| ? dynamicEvaluator(descriptor, fragment) |
| : staticEvaluator(fragment)) |
| .toArray(FragmentEvaluator[]::new); |
| } |
| |
| private static FragmentEvaluator staticEvaluator(TemplateParser.TextFragment fragment) { |
| final String text = fragment.fragment(); |
| return (builder, unused) -> builder.append(text); |
| } |
| |
| private static FragmentEvaluator dynamicEvaluator( |
| Descriptors.Descriptor descriptor, TemplateParser.TextFragment fragment) { |
| final Function<Message, ?> protopathEvaluator = |
| ProtobufPath.protobufPath(descriptor, fragment.fragment()); |
| return (builder, message) -> { |
| Object result = protopathEvaluator.apply(message); |
| builder.append(result); |
| }; |
| } |
| } |