Log to webrtc logging stream from java code.

talk/app/webrtc/java/src/org/webrtc/Logging.java

 /*
  * libjingle
  * Copyright 2013 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
  *     this list of conditions and the following disclaimer in the documentation
  *     and/or other materials provided with the distribution.
  *  3. The name of the author may not be used to endorse or promote products
  *     derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 package org.webrtc;
 
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.nio.charset.Charset;
 import java.util.EnumSet;
 
 /** Java wrapper for WebRTC & libjingle logging. */
 public class Logging {
   static {
     System.loadLibrary("jingle_peerconnection_so");
   }
 
   // Keep in sync with webrtc/common_types.h:TraceLevel.
   public enum TraceLevel {
@@ skipping 37 matching lines @@
   public static void enableTracing(
       String path, EnumSet<TraceLevel> levels, Severity severity) {
     int nativeLevel = 0;
     for (TraceLevel level : levels) {
       nativeLevel |= level.level;
     }
     nativeEnableTracing(path, nativeLevel, severity.ordinal());
   }
 
   public static void log(Severity severity, String tag, String message) {
-    nativeLog(severity.ordinal(), tag + ": " + message);
+    nativeLog(severity.ordinal(), tag, message);
+  }
+
+  public static void d(String tag, String message) {
+    log(Severity.LS_INFO, tag, message);
+  }
+
+  public static void e(String tag, String message) {
+    log(Severity.LS_ERROR, tag, message);
+  }
+
+  public static void w(String tag, String message) {
+    log(Severity.LS_WARNING, tag, message);
+  }
+
+  public static void e(String tag, String message, Throwable e) {
+    log(Severity.LS_ERROR, tag, message);
+    log(Severity.LS_ERROR, tag, e.toString());
+    log(Severity.LS_ERROR, tag, getStackTraceAsString(e));
+  }
+
+  public static void w(String tag, String message, Throwable e) {
+    log(Severity.LS_WARNING, tag, message);
+    log(Severity.LS_WARNING, tag, e.toString());
+    log(Severity.LS_WARNING, tag, getStackTraceAsString(e));
+  }
+
+  public static void v(String tag, String message) {
+    log(Severity.LS_VERBOSE, tag, message);
+  }
+
+  private static String getStackTraceAsString(Throwable e) {

[AlexG, 2015/09/14 20:12:33]

May be mimic Android implementation here (getStackTraceString() from 
https://android.googlesource.com/platform/frameworks/base/+/534a67c/core/java...
)?

[jiayl2, 2015/09/14 20:54:38]

Done.

+    ByteArrayOutputStream ostream = new ByteArrayOutputStream();
+    PrintStream pstream = new PrintStream(ostream);
+    e.printStackTrace(pstream);
+    return ostream.toString();
   }
 
   private static native void nativeEnableTracing(
       String path, int nativeLevels, int nativeSeverity);
   private static native void nativeEnableLogThreads();
   private static native void nativeEnableLogTimeStamps();
-  private static native void nativeLog(int severity, String message);
+  private static native void nativeLog(int severity, String tag, String message);
 }