1 files changed, 126 insertions, 0 deletions
diff --git a/java/src/c/helper.c b/java/src/c/helper.c
new file mode 100644
index 00000000..b1e5c8f3
--- /dev/null
+++ b/java/src/c/helper.c
@@ -0,0 +1,126 @@
+/* $Id$
+ *
+ * JLasso -- Java bindings for Lasso library
+ *
+ * Copyright (C) 2004 Entr'ouvert
+ * http://lasso.labs.libre-entreprise.org
+ *
+ * Authors: Benjamin Poussin <poussin@codelutin.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <helper.h>
+
+void * getObjectRef(JNIEnv * env, jobject this, const char * name){
+    jclass clazz;
+    jfieldID fid;
+    jlong result;
+
+    clazz = (*env)->GetObjectClass(env, this);
+    fid = (*env)->GetFieldID(env, clazz, name, "J");
+
+    result = (*env)->GetLongField(env, this, fid);
+    return (void*)(long)result;
+}
+
+void setObjectRef(JNIEnv * env, jobject this, const char * name, void * objectRef){
+    jclass clazz;
+    jfieldID fid;
+    jlong ref;
+
+    clazz = (*env)->GetObjectClass(env, this);
+    fid = (*env)->GetFieldID(env, clazz, name, "J");
+
+    ref = (jlong)(long)objectRef;
+    (*env)->SetLongField(env, this, fid, ref);
+}
+
+
+void storeCObject(JNIEnv * env, jobject this, void * cobject){
+    setObjectRef(env, this, "c_lasso_object", cobject);
+}
+
+void* getCObject(JNIEnv * env, jobject this){
+    return getObjectRef(env, this, "c_lasso_object");
+}
+
+
+jobject getJavaObjectField(JNIEnv * env, jobject this, const char * fieldName, const char * fieldType){
+    jclass clazz;
+    jfieldID fid;
+    jobject result;
+
+    clazz = (*env)->GetObjectClass(env, this);
+    fid = (*env)->GetFieldID(env, clazz, fieldName, fieldType);
+
+    result = (*env)->GetObjectField(env, this, fid);
+    return result;
+}
+
+void setJavaObjectField(JNIEnv * env, jobject this, const char * fieldName, const char * fieldType, jobject value){
+    jclass clazz;
+    jfieldID fid;
+
+    clazz = (*env)->GetObjectClass(env, this);
+    fid = (*env)->GetFieldID(env, clazz, fieldName, fieldType);
+
+    (*env)->SetObjectField(env, this, fid, value);
+}
+
+jobject instanciate(JNIEnv * env, const char * className){
+    jclass clazz;
+    jmethodID constructor;
+    jobject result;
+
+    clazz = (*env)->FindClass(env, className);
+    if (clazz == NULL) {
+        return NULL; /* exception thrown */
+    }
+    constructor = (*env)->GetMethodID(env, clazz, "<init>", "()V");
+    if (constructor == NULL) {
+        return NULL; /* exception thrown */
+    }
+
+    result = (*env)->NewObject(env, clazz, constructor);
+    (*env)->DeleteLocalRef(env, clazz);
+
+    return result;
+}
+
+int isSameObject(JNIEnv * env, jobject javaObject, void* cObject){
+    return javaObject != NULL && cObject == getCObject(env, javaObject);
+}
+
+void checkAndSetField(JNIEnv * env, jobject this, char * fieldName,
+char * fieldType, char * javaObjectClassName, void * cObject){
+    jobject javaObject;
+
+    // check if change are made
+    javaObject = getJavaObjectField(env, this, fieldName, fieldType);
+    if(isSameObject(env, javaObject, cObject)){
+        // no change made, do nothing
+        return;
+    }
+
+    javaObject = instanciate(env, javaObjectClassName);
+    if(javaObject == NULL){
+        return; /* exception thrown */
+    }
+
+    // associate C object with JavaObject
+    storeCObject(env, javaObject, cObject);
+    setJavaObjectField(env, this, fieldName, fieldType, javaObject);
+}