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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   https://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  
20  package org.apache.bcel;
21  
22  public class NanoTimer {
23  
24      private long timeNanos;
25  
26      public void reset() {
27          timeNanos = 0;
28      }
29  
30      public NanoTimer start() {
31          timeNanos -= System.nanoTime();
32          return this;
33      }
34  
35      public void stop() {
36          timeNanos += System.nanoTime();
37      }
38  
39      public void subtract(final NanoTimer o) {
40          timeNanos -= o.timeNanos;
41      }
42  
43      /**
44       * May ony be called after stop has been called as many times as start.
45       */
46      @Override
47      public String toString() {
48          return (double) timeNanos / 1000000000 + " s";
49      }
50  
51  }