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.server.core.alarm.provider;
  
  import static java.util.Objects.requireNonNull;
  
  public enum OP {
      GT {
          @Override
          public boolean test(final Number expected, final Number actual) {
              return requireNonNull(actual, "actual").doubleValue() > requireNonNull(expected, "expected").doubleValue();
          }
      },
  
      GTE {
          @Override
          public boolean test(final Number expected, final Number actual) {
              return requireNonNull(actual, "actual").doubleValue() >= requireNonNull(expected, "expected").doubleValue();
          }
      },
  
      LT {
          @Override
          public boolean test(final Number expected, final Number actual) {
              return requireNonNull(actual, "actual").doubleValue() < requireNonNull(expected, "expected").doubleValue();
          }
      },
  
      LTE {
          @Override
          public boolean test(final Number expected, final Number actual) {
              return requireNonNull(actual, "actual").doubleValue() <= requireNonNull(expected, "expected").doubleValue();
          }
      },
  
      // NOTICE: double equal is not reliable in Java,
      // match result is not predictable
      EQ {
          @Override
          public boolean test(final Number expected, final Number actual) {
              return requireNonNull(actual, "actual").doubleValue() == requireNonNull(expected, "expected").doubleValue();
          }
      },
  
      NEQ {
          @Override
          public boolean test(final Number expected, final Number actual) {
              return requireNonNull(actual, "actual").doubleValue() != requireNonNull(expected, "expected").doubleValue();
          }
      };
  
      public static OP get(String op) {
          switch (op) {
              case ">":
                  return GT;
              case ">=":
                  return GTE;
              case "<":
                  return LT;
              case "<=":
                  return LTE;
              case "==":
                  return EQ;
              case "!=":
                  return NEQ;
              default:
                  throw new IllegalArgumentException("unknown op, " + op);
          }
      }
  
      public abstract boolean test(final Number expected, final Number actual);
  }
  