code: /*
   * 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.skywalking.oap.meter.analyzer.dsl;
  
  import groovy.lang.Closure;
  import groovy.lang.GroovyShell;
  import java.util.Map;
  import lombok.ToString;
  import lombok.extern.slf4j.Slf4j;
  
  import static java.util.stream.Collectors.toMap;
  
  @Slf4j
  @ToString(of = {"literal"})
  public class FilterExpression {
      private final String literal;
      private final Closure<Boolean> filterClosure;
  
      @SuppressWarnings("unchecked")
      public FilterExpression(final String literal) {
          this.literal = literal;
  
          GroovyShell sh = new GroovyShell();
          filterClosure = (Closure<Boolean>) sh.evaluate(literal);
      }
  
      public Map<String, SampleFamily> filter(final Map<String, SampleFamily> sampleFamilies) {
          try {
              return sampleFamilies.entrySet().stream().collect(toMap(
                  Map.Entry::getKey,
                  it -> it.getValue().filter(filterClosure)
              ));
          } catch (Throwable t) {
              log.error("failed to run \"{}\"", literal, t);
          }
          return sampleFamilies;
      }
  }
  