JACOBIN-340 Filled in logic for native method for Class.getPrimitiveC…

…lass()

src/classloader/javalangClass.go

@@ -6,12 +6,59 @@
 
 package classloader
 
-// Implementation of some of the functions in in Java/lang/Class. Starting with getPrimitiveInsance()
+import (
+	"errors"
+	"jacobin/log"
+	"jacobin/shutdown"
+)
 
-func getPrimitiveClass(primitive string) Klass {
+// Implementation of some of the functions in in Java/lang/Class.
+
+func Load_Lang_Class() map[string]GMeth {
+
+	MethodSignatures["java/lang/Class.getPrimitiveClass(Ljava/lang/String;)Ljava/lang/Class;"] =
+		GMeth{
+			ParamSlots: 1,
+			GFunction:  getPrimitiveClass,
+		}
+
+	return MethodSignatures
+}
+
+// getPrimitiveClass() takes a one-word descriptor of a primitive and
+// returns the native primitive class that corresponds to it. Not
+// quite sure how this class is used, but it needs to implemented.
+func getPrimitiveClass(params []interface{}) interface{} {
+	primitive := params[0].(string)
 	if primitive == "int" {
-		// do somethng
-		return Klass{}
+		k, err := simpleClassLoadByName("java/lang/Integer")
+		if err != nil {
+			return errors.New("getPrimitiveClass() could not load java/lang/Integer")
+		} else {
+			return k
+		}
+	}
+	return errors.New("getPrimitiveClass() reached unreadhable code")
+}
+
+// simpleClassLoadByName() just checks the MethodArea cache for the loaded
+// class, and if it's not there, it loads it and returns a pointer to it.
+// Logic basically duplicates similar functionality in instantiate.go
+func simpleClassLoadByName(className string) (*Klass, error) {
+	alreadyLoaded := MethAreaFetch(className)
+	if alreadyLoaded != nil { // if the class is already loaded, skip the rest of this
+		return alreadyLoaded, nil
+	}
+
+	// If not, try to load class by name
+	err := LoadClassFromNameOnly(className)
+	if err != nil {
+		errMsg := "instantiateClass()-getPrimitivelass(): Failed to load class " + className
+		_ = log.Log(errMsg, log.SEVERE)
+		_ = log.Log(err.Error(), log.SEVERE)
+		shutdown.Exit(shutdown.APP_EXCEPTION)
+		return nil, errors.New(errMsg) // needed for testing, which does not shutdown on failure
+	} else {
+		return MethAreaFetch(className), nil
 	}
-	return Klass{} // should be a void class or the like.
 }

src/classloader/mTable.go

@@ -74,6 +74,7 @@ var MTmutex sync.Mutex
 // they make available.
 func MTableLoadNatives() {
 	loadlib(&MTable, Load_Io_PrintStream()) // load the java.io.prinstream golang functions
+	loadlib(&MTable, Load_Lang_Class())     // load the java.lang.Class golang functions
 	loadlib(&MTable, Load_Lang_System())    // load the java.lang.system golang functions
 	loadlib(&MTable, Load_Lang_Math())      // load the java.lang.system golang functions
 }