Java API for opening/closing SG databases

src/runtime/java/jsg.c

@@ -0,0 +1,79 @@
+#include <jni.h>
+#include <sg/sg.h>
+#include "jni_utils.h"
+
+JNIEXPORT jobject JNICALL
+Java_org_grammaticalframework_sg_SG_openSG(JNIEnv *env, jclass cls, jstring path)
+{
+	GuPool* tmp_pool = gu_local_pool();
+
+	// Create an exception frame that catches all errors.
+	GuExn* err = gu_exn(tmp_pool);
+
+	const char *fpath = (*env)->GetStringUTFChars(env, path, 0); 
+
+	// Read the PGF grammar.
+	SgSG* sg = sg_open(fpath, err);
+
+	(*env)->ReleaseStringUTFChars(env, path, fpath);
+
+	if (!gu_ok(err)) {
+		GuString msg;
+		if (gu_exn_caught(err, SgError)) {
+			msg = (GuString) gu_exn_caught_data(err);
+		} else {
+			msg = "The database cannot be opened";
+		}
+		throw_string_exception(env, "org/grammaticalframework/sg/SGError", msg);
+		gu_pool_free(tmp_pool);
+		return NULL;
+	}
+
+	gu_pool_free(tmp_pool);
+
+	jmethodID constrId = (*env)->GetMethodID(env, cls, "<init>", "(J)V");
+	return (*env)->NewObject(env, cls, constrId, p2l(sg));
+}
+
+JNIEXPORT void JNICALL
+Java_org_grammaticalframework_sg_SG_close(JNIEnv *env, jobject self)
+{
+	GuPool* tmp_pool = gu_local_pool();
+
+	// Create an exception frame that catches all errors.
+	GuExn* err = gu_exn(tmp_pool);
+
+	sg_close(get_ref(env, self), err);
+	if (!gu_ok(err)) {
+		GuString msg;
+		if (gu_exn_caught(err, SgError)) {
+			msg = (GuString) gu_exn_caught_data(err);
+		} else {
+			msg = "The database cannot be closed";
+		}
+		throw_string_exception(env, "org/grammaticalframework/sg/SGError", msg);
+		gu_pool_free(tmp_pool);
+		return;
+	}
+
+	gu_pool_free(tmp_pool);
+}
+
+JNIEXPORT jobject JNICALL
+Java_org_grammaticalframework_sg_SG_queryTriple(JNIEnv *env, jobject self,
+                                                jobject subj,
+                                                jobject pred,
+                                                jobject obj)
+{
+	return NULL;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_org_grammaticalframework_sg_TripleResult_hasNext(JNIEnv *env, jobject self)
+{
+}
+
+JNIEXPORT void JNICALL
+Java_org_grammaticalframework_sg_TripleResult_close(JNIEnv *env, jobject self)
+{
+}