[lttng-dev] [LTTng-UST PATCH] Make the JNI interface actually work

Alexandre Montplaisir alexandre.montplaisir at polymtl.ca
Thu Apr 5 16:52:52 EDT 2012


Now a user can import LTTngUst.java (which is now in a proper
package) and then define tracepoints in his application with:

LTTngUst.tracepointString(name, args);

We could eventually ship it in a .jar when the JNI interface is
enabled. It's still very basic, only string payloads are
implemented, and there is no mechanism to enable/disable trace
points at runtime.

Signed-off-by: Alexandre Montplaisir <alexandre.montplaisir at polymtl.ca>
---
 liblttng-ust-java/.gitignore     |    4 +-
 liblttng-ust-java/LTTNG_UST.c    |   36 -----------------------------------
 liblttng-ust-java/LTTNG_UST.java |   25 ------------------------
 liblttng-ust-java/LTTngUst.c     |   39 ++++++++++++++++++++++++++++++++++++++
 liblttng-ust-java/LTTngUst.java  |   27 ++++++++++++++++++++++++++
 liblttng-ust-java/Makefile.am    |   17 ++++++++-------
 6 files changed, 77 insertions(+), 71 deletions(-)
 delete mode 100644 liblttng-ust-java/LTTNG_UST.c
 delete mode 100644 liblttng-ust-java/LTTNG_UST.java
 create mode 100644 liblttng-ust-java/LTTngUst.c
 create mode 100644 liblttng-ust-java/LTTngUst.java

diff --git a/liblttng-ust-java/.gitignore b/liblttng-ust-java/.gitignore
index ab97d04..677373e 100644
--- a/liblttng-ust-java/.gitignore
+++ b/liblttng-ust-java/.gitignore
@@ -1,2 +1,2 @@
-UST.class
-UST.h
+org_lttng_ust_LTTngUst.h
+org/
diff --git a/liblttng-ust-java/LTTNG_UST.c b/liblttng-ust-java/LTTNG_UST.c
deleted file mode 100644
index af29c1e..0000000
--- a/liblttng-ust-java/LTTNG_UST.c
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <jni.h>
-
-#define TRACEPOINT_DEFINE
-#define TRACEPOINT_CREATE_PROBES
-#include "lttng_ust_java.h"
-
-JNIEXPORT void JNICALL Java_LTTNG_UST_ust_1java_1event (JNIEnv *env,
-						jobject jobj,
-						jstring ev_name,
-						jstring args)
-{
-	jboolean iscopy;
-	const char *ev_name_cstr = (*env)->GetStringUTFChars(env, ev_name,
-							&iscopy);
-	const char *args_cstr = (*env)->GetStringUTFChars(env, args, &iscopy);
-
-	tracepoint(lttng_ust_java, string, ev_name_cstr, args_cstr);
-}
diff --git a/liblttng-ust-java/LTTNG_UST.java b/liblttng-ust-java/LTTNG_UST.java
deleted file mode 100644
index 7ec6110..0000000
--- a/liblttng-ust-java/LTTNG_UST.java
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-class LTTNG_UST {
-	public static native void lttng_ust_java_string(String name, String arg);
-	static {
-		System.loadLibrary("lttng-ust-java");
-	}
-}
-
diff --git a/liblttng-ust-java/LTTngUst.c b/liblttng-ust-java/LTTngUst.c
new file mode 100644
index 0000000..3d23d6a
--- /dev/null
+++ b/liblttng-ust-java/LTTngUst.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <jni.h>
+
+#define TRACEPOINT_DEFINE
+#define TRACEPOINT_CREATE_PROBES
+#include "lttng_ust_java.h"
+
+JNIEXPORT void JNICALL Java_org_lttng_ust_LTTngUst_tracepointString(JNIEnv *env,
+						jobject jobj,
+						jstring ev_name,
+						jstring args)
+{
+	jboolean iscopy;
+	const char *ev_name_cstr = (*env)->GetStringUTFChars(env, ev_name,
+							&iscopy);
+	const char *args_cstr = (*env)->GetStringUTFChars(env, args, &iscopy);
+
+	tracepoint(lttng_ust_java, string, ev_name_cstr, args_cstr);
+
+	(*env)->ReleaseStringUTFChars(env, ev_name, ev_name_cstr);
+	(*env)->ReleaseStringUTFChars(env, args, args_cstr);
+}
diff --git a/liblttng-ust-java/LTTngUst.java b/liblttng-ust-java/LTTngUst.java
new file mode 100644
index 0000000..d3f1eda
--- /dev/null
+++ b/liblttng-ust-java/LTTngUst.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+package org.lttng.ust;
+
+class LTTngUst {
+	public static native void tracepointString(String name, String arg);
+	static {
+		System.loadLibrary("lttng-ust-java");
+	}
+}
+
diff --git a/liblttng-ust-java/Makefile.am b/liblttng-ust-java/Makefile.am
index 31915d0..9e01e04 100644
--- a/liblttng-ust-java/Makefile.am
+++ b/liblttng-ust-java/Makefile.am
@@ -3,19 +3,20 @@ if BUILD_JNI_INTERFACE
 AM_CPPFLAGS = -I$(top_srcdir)/include
 
 lib_LTLIBRARIES = liblttng-ust-java.la
-liblttng_ust_java_la_SOURCES = LTTNG_UST.c LTTNG_UST.h lttng_ust_java.h
-dist_noinst_DATA = LTTNG_UST.java
+liblttng_ust_java_la_SOURCES = LTTngUst.c org_lttng_ust_LTTngUst.h lttng_ust_java.h
+dist_noinst_DATA = LTTngUst.java
 liblttng_ust_java_la_LIBADD = -lc -L$(top_builddir)/liblttng-ust/.libs -llttng-ust
 
-all: LTTNG_UST.class LTTNG_UST.h
+all: LTTngUst.class org_lttng_ust_LTTngUst.h
 
 clean-local:
-	rm -rf LTTNG_UST.h LTTNG_UST.class
+	rm  org_lttng_ust_LTTngUst.h
+	rm -rf org/
 
-LTTNG_UST.class: LTTNG_UST.java
-	javac -d "$(builddir)" "$(srcdir)/LTTNG_UST.java"
+LTTngUst.class: LTTngUst.java
+	javac -d "$(builddir)" "$(srcdir)/LTTngUst.java"
 
-LTTNG_UST.h: LTTNG_UST.class
-	javah -classpath ./ -jni LTTNG_UST
+org_lttng_ust_LTTngUst.h: LTTngUst.class
+	javah org.lttng.ust.LTTngUst
 
 endif
-- 
1.7.9.1




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