code: /**
   * Copyright 2016 Alexey Ragozin
   *
   * Licensed 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.gridkit.jvmtool.stacktrace.analytics.flame;
  
  import java.util.Comparator;
  
  import org.gridkit.jvmtool.stacktrace.GenericStackElement;
  import org.gridkit.jvmtool.stacktrace.StackFrame;
  import org.gridkit.jvmtool.stacktrace.analytics.WeigthCalculator;
  
  /**
   * Specialization of {@link GenericFlameGraphGenerator} working
   * with Java stack traces.
   *
   * @author Alexey Ragozin (alexey.ragozin@gmail.com)
   */
  public class FlameGraphGenerator extends GenericFlameGraphGenerator {
  
      private static final FrameComparator FRAME_COMPARATOR = new FrameComparator();
  
      public FlameGraphGenerator() {
          super();
      }
  
      public FlameGraphGenerator(WeigthCalculator calculator) {
          super(calculator);
      }
  
      @Override
      @SuppressWarnings({ "rawtypes", "unchecked" })
      protected Comparator<GenericStackElement> comparator() {
          return (Comparator)FRAME_COMPARATOR;
      }
  
      @Override
      protected String describe(Node node) {
          StackFrame frame = (StackFrame) node.path[node.path.length - 1];
          String line = frame.getClassName() + "." + frame.getMethodName();
          line = line.replace((CharSequence)"<", "&lt;");
          line = line.replace((CharSequence)">", "&gt;");
          return line;
      }
  
      private static class FrameComparator implements Comparator<StackFrame> {
  
          @Override
          public int compare(StackFrame o1, StackFrame o2) {
              int n = compare(o1.getClassName(), o2.getClassName());
              if (n != 0) {
                  return n;
              }
              n = compare(o1.getLineNumber(), o2.getLineNumber());
              if (n != 0) {
                  return n;
              }
              n = compare(o1.getMethodName(), o2.getMethodName());
              if (n != 0) {
                  return n;
              }
              n = compare(o1.getSourceFile(), o2.getSourceFile());
              return 0;
          }
  
          private int compare(int n1, int n2) {
              return Long.signum(((long)n1) - ((long)n2));
          }
  
          private int compare(String str1, String str2) {
              if (str1 == str2) {
                  return 0;
              }
              else if (str1 == null) {
                  return -1;
              }
              else if (str2 == null) {
                  return 1;
              }
              return str1.compareTo(str2);
          }
      }
  }
  