ceph/src/rocksdb/java/src/main/java/org/rocksdb/Env.java

   1 // Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 // This source code is licensed under the BSD-style license found in the
   3 // LICENSE file in the root directory of this source tree. An additional grant
   4 // of patent rights can be found in the PATENTS file in the same directory.
   5
   6 package org.rocksdb;
   7
   8 /**
   9  * Base class for all Env implementations in RocksDB.
  10  */
  11 public abstract class Env extends RocksObject {
  12   public static final int FLUSH_POOL = 0;
  13   public static final int COMPACTION_POOL = 1;
  14
  15   /**
  16    * <p>Returns the default environment suitable for the current operating
  17    * system.</p>
  18    *
  19    * <p>The result of {@code getDefault()} is a singleton whose ownership
  20    * belongs to rocksdb c++.  As a result, the returned RocksEnv will not
  21    * have the ownership of its c++ resource, and calling its dispose()
  22    * will be no-op.</p>
  23    *
  24    * @return the default {@link org.rocksdb.RocksEnv} instance.
  25    */
  26   public static Env getDefault() {
  27     return default_env_;
  28   }
  29
  30   /**
  31    * <p>Sets the number of background worker threads of the flush pool
  32    * for this environment.</p>
  33    * <p>Default number: 1</p>
  34    *
  35    * @param num the number of threads
  36    *
  37    * @return current {@link RocksEnv} instance.
  38    */
  39   public Env setBackgroundThreads(final int num) {
  40     return setBackgroundThreads(num, FLUSH_POOL);
  41   }
  42
  43   /**
  44    * <p>Sets the number of background worker threads of the specified thread
  45    * pool for this environment.</p>
  46    *
  47    * @param num the number of threads
  48    * @param poolID the id to specified a thread pool.  Should be either
  49    *     FLUSH_POOL or COMPACTION_POOL.
  50    *
  51    * <p>Default number: 1</p>
  52    * @return current {@link RocksEnv} instance.
  53    */
  54   public Env setBackgroundThreads(final int num, final int poolID) {
  55     setBackgroundThreads(nativeHandle_, num, poolID);
  56     return this;
  57   }
  58
  59   /**
  60    * <p>Returns the length of the queue associated with the specified
  61    * thread pool.</p>
  62    *
  63    * @param poolID the id to specified a thread pool.  Should be either
  64    *     FLUSH_POOL or COMPACTION_POOL.
  65    *
  66    * @return the thread pool queue length.
  67    */
  68   public int getThreadPoolQueueLen(final int poolID) {
  69     return getThreadPoolQueueLen(nativeHandle_, poolID);
  70   }
  71
  72
  73   protected Env(final long nativeHandle) {
  74     super(nativeHandle);
  75   }
  76
  77   static {
  78     default_env_ = new RocksEnv(getDefaultEnvInternal());
  79   }
  80
  81   /**
  82    * <p>The static default Env. The ownership of its native handle
  83    * belongs to rocksdb c++ and is not able to be released on the Java
  84    * side.</p>
  85    */
  86   static Env default_env_;
  87
  88   private static native long getDefaultEnvInternal();
  89   private native void setBackgroundThreads(
  90       long handle, int num, int priority);
  91   private native int getThreadPoolQueueLen(long handle, int poolID);
  92 }