liblttng-ust-java-agent/java/org/lttng/ust/agent/LogFrameworkSkeleton.java

   1 /*
   2  * Copyright (C) 2014 - Christian Babeux <christian.babeux@efficios.com>
   3  *
   4  *
   5  * This library is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU Lesser General Public License, version 2.1 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This library is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
  12  * for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this library; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 package org.lttng.ust.agent;
  20
  21 import java.util.Map;
  22 import java.util.HashMap;
  23 import java.util.Iterator;
  24
  25 public abstract class LogFrameworkSkeleton implements LogFramework {
  26
  27         /* A map of event name and reference count */
  28         private Map<String, Integer> enabledLoggers;
  29
  30         public LogFrameworkSkeleton() {
  31                 this.enabledLoggers = new HashMap<String, Integer>();
  32         }
  33
  34         @Override
  35         public Boolean enableLogger(String name) {
  36                 if (name == null) {
  37                         return false;
  38                 }
  39
  40                 if (enabledLoggers.containsKey(name)) {
  41                         /* Event is already enabled, simply increment its refcount */
  42                         Integer refcount = enabledLoggers.get(name);
  43                         refcount++;
  44                         Integer oldval = enabledLoggers.put(name, refcount);
  45                         assert (oldval != null);
  46                 } else {
  47                         /* Event was not enabled, init refcount to 1 */
  48                         Integer oldval = enabledLoggers.put(name, 1);
  49                         assert (oldval == null);
  50                 }
  51
  52                 return true;
  53         }
  54
  55         @Override
  56         public Boolean disableLogger(String name) {
  57                 if (name == null) {
  58                         return false;
  59                 }
  60
  61                 if (!enabledLoggers.containsKey(name)) {
  62                         /* Event was never enabled, abort */
  63                         return false;
  64                 }
  65
  66                 /* Event was previously enabled, simply decrement its refcount */
  67                 Integer refcount = enabledLoggers.get(name);
  68                 refcount--;
  69                 assert (refcount >= 0);
  70
  71                 if (refcount == 0) {
  72                         /* Event is not used anymore, remove it from the map */
  73                         Integer oldval = enabledLoggers.remove(name);
  74                         assert (oldval != null);
  75                 }
  76
  77                 return true;
  78         }
  79
  80         @Override
  81         public abstract Iterator<String> listLoggers();
  82
  83         @Override
  84         public abstract Boolean isRoot();
  85
  86         @Override
  87         public void reset() {
  88                 enabledLoggers.clear();
  89         }
  90
  91         protected Integer getEventCount() {
  92                 return enabledLoggers.size();
  93         }
  94 }