src/jdk.compiler/share/classes/com/sun/tools/javac/api/JavacTaskPool.java

rev 50962 : [mq]: 8206122-Use-Queue-in-place-of-ArrayList-when-need-to-remove-first-element

*** 1,7 ****
  /*
!  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
--- 1,7 ----
  /*
!  * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
*** 25,38 ****
  
  package com.sun.tools.javac.api;
  
  import java.io.PrintStream;
  import java.io.Writer;
  import java.util.ArrayList;
  import java.util.Collection;
- import java.util.Collections;
  import java.util.HashMap;
  
  import com.sun.source.tree.ClassTree;
  import com.sun.source.tree.CompilationUnitTree;
  import com.sun.source.util.JavacTask;
  import com.sun.source.util.TaskEvent;
--- 25,50 ----
  
  package com.sun.tools.javac.api;
  
  import java.io.PrintStream;
  import java.io.Writer;
+ import java.util.ArrayDeque;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
+ import java.util.HashSet;
+ import java.util.List;
+ import java.util.Map;
+ import java.util.Queue;
+ import java.util.Set;
+ import java.util.stream.Collectors;
+ import java.util.stream.StreamSupport;
+ 
+ import javax.tools.Diagnostic;
+ import javax.tools.DiagnosticListener;
+ import javax.tools.JavaFileManager;
+ import javax.tools.JavaFileObject;
  
  import com.sun.source.tree.ClassTree;
  import com.sun.source.tree.CompilationUnitTree;
  import com.sun.source.util.JavacTask;
  import com.sun.source.util.TaskEvent;
*** 51,75 ****
  import com.sun.tools.javac.comp.CompileStates;
  import com.sun.tools.javac.comp.Enter;
  import com.sun.tools.javac.comp.Modules;
  import com.sun.tools.javac.main.Arguments;
  import com.sun.tools.javac.main.JavaCompiler;
- import com.sun.tools.javac.tree.JCTree.JCClassDecl;
- 
- import javax.tools.Diagnostic;
- import javax.tools.DiagnosticListener;
- import javax.tools.JavaFileManager;
- import javax.tools.JavaFileObject;
- 
- import java.util.HashSet;
- import java.util.List;
- import java.util.Map;
- import java.util.Set;
- import java.util.stream.Collectors;
- import java.util.stream.StreamSupport;
- 
  import com.sun.tools.javac.model.JavacElements;
  import com.sun.tools.javac.util.Context;
  import com.sun.tools.javac.util.DefinedBy;
  import com.sun.tools.javac.util.DefinedBy.Api;
  import com.sun.tools.javac.util.Log;
  
--- 63,74 ----
  import com.sun.tools.javac.comp.CompileStates;
  import com.sun.tools.javac.comp.Enter;
  import com.sun.tools.javac.comp.Modules;
  import com.sun.tools.javac.main.Arguments;
  import com.sun.tools.javac.main.JavaCompiler;
  import com.sun.tools.javac.model.JavacElements;
+ import com.sun.tools.javac.tree.JCTree.JCClassDecl;
  import com.sun.tools.javac.util.Context;
  import com.sun.tools.javac.util.DefinedBy;
  import com.sun.tools.javac.util.DefinedBy.Api;
  import com.sun.tools.javac.util.Log;
  
*** 99,111 ****
   * deletion without notice.</b>
   */
  public class JavacTaskPool {
  
      private static final JavacTool systemProvider = JavacTool.create();
  
      private final int maxPoolSize;
!     private final Map<List<String>, List<ReusableContext>> options2Contexts = new HashMap<>();
      private int id;
  
      private int statReused = 0;
      private int statNew = 0;
      private int statPolluted = 0;
--- 98,111 ----
   * deletion without notice.</b>
   */
  public class JavacTaskPool {
  
      private static final JavacTool systemProvider = JavacTool.create();
+     private static final Queue<ReusableContext> EMPTY_QUEUE = new ArrayDeque<>(0);
  
      private final int maxPoolSize;
!     private final Map<List<String>, Queue<ReusableContext>> options2Contexts = new HashMap<>();
      private int id;
  
      private int statReused = 0;
      private int statNew = 0;
      private int statPolluted = 0;
*** 157,174 ****
                               .collect(Collectors.toCollection(ArrayList::new));
  
          ReusableContext ctx;
  
          synchronized (this) {
!             List<ReusableContext> cached =
!                     options2Contexts.getOrDefault(opts, Collections.emptyList());
  
              if (cached.isEmpty()) {
                  ctx = new ReusableContext(opts);
                  statNew++;
              } else {
!                 ctx = cached.remove(0);
                  statReused++;
              }
          }
  
          ctx.useCount++;
--- 157,174 ----
                               .collect(Collectors.toCollection(ArrayList::new));
  
          ReusableContext ctx;
  
          synchronized (this) {
!             Queue<ReusableContext> cached =
!                     options2Contexts.getOrDefault(opts, EMPTY_QUEUE);
  
              if (cached.isEmpty()) {
                  ctx = new ReusableContext(opts);
                  statNew++;
              } else {
!                 ctx = cached.remove();
                  statReused++;
              }
          }
  
          ctx.useCount++;
*** 198,208 ****
                                              .findFirst()
                                              .get();
                      options2Contexts.get(toRemove.arguments).remove(toRemove);
                      statRemoved++;
                  }
!                 options2Contexts.computeIfAbsent(ctx.arguments, x -> new ArrayList<>()).add(ctx);
                  ctx.timeStamp = id++;
              }
          }
  
          return result;
--- 198,208 ----
                                              .findFirst()
                                              .get();
                      options2Contexts.get(toRemove.arguments).remove(toRemove);
                      statRemoved++;
                  }
!                 options2Contexts.computeIfAbsent(ctx.arguments, x -> new ArrayDeque<>()).add(ctx);
                  ctx.timeStamp = id++;
              }
          }
  
          return result;