javaClass.cpp

#include "JavaClass.h"

size_t allocations;
map<int,JavaClass*> JavaClass::instances;

JavaClass::JavaClass(const char* inputJavaClassName): javaClassName(inputJavaClassName), refid(allocations++) {
	JavaClass::instances.insert(std::pair<int,JavaClass*>(refid,this));
	
	JNIEnv *env = ofGetJNIEnv();
	jclass clazz = getJavaClass();
	jmethodID javaConstructor = JavaClass::getMethodID(clazz,"<init>","I","V");
	if(!javaConstructor){
		ofLogError("JavaClass") << " couldn't find constructor for " << javaClassName << ".\n";
		return;
	}
	javaObject = env->NewObject(clazz,javaConstructor,refid);
	if(!javaObject){
		ofLogError("JavaClass") << " couldn't create instance for " << javaClassName << ".\n";
		return;
	}
	javaObject = (jobject)env->NewGlobalRef(javaObject);
}

JavaClass::~JavaClass(){
	ofGetJNIEnv()->DeleteGlobalRef(javaObject);
	JavaClass::instances.erase(refid);
}

jclass JavaClass::getJavaClass(){
	jclass javaClass = ofGetJNIEnv()->FindClass(javaClassName);
	if(!javaClass){
		ofLogError("JavaObject::getJavaClass") << "unable to find " << javaClassName << " class.";
	}
	return javaClass;
}

// Static

/*static*/ const char* JavaClass::createSignature(const char* params,const char* returnType){
	char* result = new char[strlen(params) + 2 + strlen(returnType)];
	sprintf(result,"(%s)%s",params,returnType);
	return result;
}

//- getMethodID

//--- With class

/*static*/ jmethodID JavaClass::getMethodID(jclass clazz,const char* name,const char* signature){
	return ofGetJNIEnv()->GetMethodID(clazz,name,signature);
}

/*static*/ jmethodID JavaClass::getMethodID(jclass clazz,const char* name,const char* params,const char* returnType){
	return JavaClass::getMethodID(clazz,name,JavaClass::createSignature(params,returnType));
}

//--- With object

/*static*/ jmethodID JavaClass::getMethodID(jobject object,const char* name,const char* signature){
	return JavaClass::getMethodID(ofGetJNIEnv()->GetObjectClass(object),name,signature);
}

/*static*/ jmethodID JavaClass::getMethodID(jobject object,const char* name,const char* params,const char* returnType){
	return JavaClass::getMethodID(ofGetJNIEnv()->GetObjectClass(object),name,params,returnType);
}

//- getFieldID

//--- With class
/*static*/ jfieldID JavaClass::getFieldID(jclass clazz,const char* name,const char* type){
	return ofGetJNIEnv()->GetFieldID(clazz,name,type);
}

//--- With object
/*static*/ jfieldID JavaClass::getFieldID(jobject object,const char* name,const char* type){
	return ofGetJNIEnv()->GetFieldID(ofGetJNIEnv()->GetObjectClass(object),name,type);
}

//-Other

/*static*/ jobject JavaClass::getObjectField(jobject object,const char* fieldName,const char* returnType){
	return ofGetJNIEnv()->GetObjectField(object,JavaClass::getFieldID(object,fieldName,returnType));
}

/*static*/ void JavaClass::setObjectField(jobject object,const char* fieldName,const char* returnType,jobject value){
	ofGetJNIEnv()->SetObjectField(object,JavaClass::getFieldID(object,fieldName,returnType),value);
}

// Members

jmethodID JavaClass::getMethodID(const char* name,const char* signature){
	return JavaClass::getMethodID(javaObject,name,signature);
}

jmethodID JavaClass::getMethodID(const char* name,const char* params,const char* returnType){
	return JavaClass::getMethodID(javaObject,name,params,returnType);
}

jfieldID JavaClass::getFieldID(const char* name,const char* type){
	return JavaClass::getFieldID(javaObject,name,type);
}

jobject JavaClass::getObjectField(const char* fieldName,const char* returnType){
	return JavaClass::getObjectField(javaObject,fieldName,returnType);
}

void JavaClass::setObjectField(const char* fieldName,const char* returnType,jobject value){
	JavaClass::setObjectField(javaObject,fieldName,returnType,value);
}

// Macros

createGetSetFieldMethod(jboolean,Boolean,"Z");
createGetSetFieldMethod(jbyte,Byte,"B");
createGetSetFieldMethod(jchar,Char,"C");
createGetSetFieldMethod(jshort,Short,"S");
createGetSetFieldMethod(jint,Int,"I");
createGetSetFieldMethod(jfloat,Float,"J");
createGetSetFieldMethod(jdouble,Double,"D");

javaClass.h

#pragma once

#include <jni.h>
#include <ofMain.h>
#include "ofxAndroid.h"

// CallMethod

#define createCallMethod(returnType,type,shortType) \
	template<typename... Args> static returnType call ## type ## Method(jobject object,const char* method,const char* params,Args... args){ \
		return ofGetJNIEnv()->Call ## type ## Method(object,JavaClass::getMethodID(object,method,params,shortType),args...); \
	} \
	template<typename... Args> returnType call ## type ## Method(const char* method,const char* params,Args... args){ \
		return JavaClass::call ## type ## Method(javaObject,method,params,args...); \
	}

// GetField

#define createGetFieldMethodHeader(returnType,type) \
	static returnType get ## type ## Field(jobject object,const char* fieldName); \
	returnType get ## type ## Field(const char* fieldName);

#define createGetFieldMethod(returnType,type,shortType) \
	/*static*/ returnType JavaClass::get ## type ## Field(jobject object,const char* fieldName){ \
		return ofGetJNIEnv()->Get ## type ## Field(object,JavaClass::getFieldID(object,fieldName,shortType)); \
	} \
	returnType JavaClass::get ## type ## Field(const char* fieldName){ \
		return JavaClass::get ## type ## Field(javaObject,fieldName); \
	}

// SetField

#define createSetFieldMethodHeader(returnType,type) \
	static void set ## type ## Field(jobject object,const char* fieldName,returnType value); \
	void set ## type ## Field(const char* fieldName,returnType value);

#define createSetFieldMethod(fieldType,type,shortType) \
	/*static*/ void JavaClass::set ## type ## Field(jobject object,const char* fieldName,fieldType value){ \
		ofGetJNIEnv()->Set ## type ## Field(object,JavaClass::getFieldID(object,fieldName,shortType),value); \
	} \
	void JavaClass::set ## type ## Field(const char* fieldName,fieldType value){ \
		JavaClass::set ## type ## Field(javaObject,fieldName,value); \
	}

// GetSet

#define createGetSetFieldMethodHeader(returnType,type) \
	createGetFieldMethodHeader(returnType,type); \
	createSetFieldMethodHeader(returnType,type);

#define createGetSetFieldMethod(returnType,type,shortType) \
	createGetFieldMethod(returnType,type,shortType); \
	createSetFieldMethod(returnType,type,shortType);


class JavaClass {
	private:
		static map<int,JavaClass*> instances;
		size_t refid;
	
	protected:
		const char* javaClassName;
		jobject javaObject;
		jclass getJavaClass();
		
	public:
		JavaClass(const char* javaClassName);
		~JavaClass();
		
		// Static
		
		static const char* createSignature(const char* params,const char* returnType);
		
		static jmethodID getMethodID(jclass clazz,const char* name,const char* signature);
		static jmethodID getMethodID(jclass clazz,const char* name,const char* params,const char* returnType);
		static jmethodID getMethodID(jobject object,const char* name,const char* signature);
		static jmethodID getMethodID(jobject object,const char* name,const char* params,const char* returnType);
		
		static jfieldID getFieldID(jclass clazz,const char* name,const char* type);
		static jfieldID getFieldID(jobject object,const char* name,const char* type);
		
		template<typename... Args> static jobject callObjectMethod(jobject object,const char* method,const char* params,const char* returnType,Args... args){
			return ofGetJNIEnv()->CallObjectMethod(object,JavaClass::getMethodID(object,method,params,returnType),args...);
		}
		
		static jobject getObjectField(jobject object,const char* fieldName,const char* returnType);
		static void setObjectField(jobject object,const char* fieldName,const char* type,jobject value);
		
		// Instance
		
		jmethodID getMethodID(const char* name,const char* signature);
		jmethodID getMethodID(const char* name,const char* params,const char* returnType);
		jfieldID getFieldID(const char* name,const char* type);
		
		template<typename... Args> jobject callObjectMethod(const char* method,const char* params,const char* returnType,Args... args){
			return JavaClass::callObjectMethod(javaObject,method,params,returnType,args...);
		}
		
		jobject getObjectField(const char* fieldName,const char* returnType);
		void setObjectField(const char* fieldName,const char* type,jobject value);	
		
		// Macros
		
		createCallMethod(void,Void,"V");
		createCallMethod(jboolean,Boolean,"Z");
		createCallMethod(jbyte,Byte,"B");
		createCallMethod(jchar,Char,"C");
		createCallMethod(jshort,Short,"S");
		createCallMethod(jint,Int,"I");
		createCallMethod(jfloat,Float,"J");
		createCallMethod(jdouble,Double,"D");
		
		createGetSetFieldMethodHeader(jboolean,Boolean);
		createGetSetFieldMethodHeader(jbyte,Byte);
		createGetSetFieldMethodHeader(jchar,Char);
		createGetSetFieldMethodHeader(jshort,Short);
		createGetSetFieldMethodHeader(jint,Int);
		createGetSetFieldMethodHeader(jfloat,Float);
		createGetSetFieldMethodHeader(jdouble,Double);
		
		template<typename Type> static Type* getNative(jobject object){
			int id = JavaClass::getIntField(object,"refid");
			try {
				return (Type*)JavaClass::instances[id];
			}
			catch(out_of_range e){
				ofLogError("JavaClass") << " couldn't find instance for id " << id << " it has probably been destroyed.\n";
			}
			return nullptr;
		}
};