--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/luan/LuanJavaFunction.java	Fri Dec 28 03:29:12 2012 +0000
@@ -0,0 +1,465 @@
+package luan;
+
+import java.lang.reflect.Array;
+import java.lang.reflect.Method;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+
+public final class LuanJavaFunction extends LuanFunction {
+	private final JavaMethod method;
+	private final Object obj;
+	private final RtnConverter rtnConverter;
+	private final boolean takesLuaState;
+	private final ArgConverter[] argConverters;
+	private final Class<?> varArgCls;
+
+	public LuanJavaFunction(Method method,Object obj) {
+		this( JavaMethod.of(method), obj );
+	}
+
+	public LuanJavaFunction(Constructor constr,Object obj) {
+		this( JavaMethod.of(constr), obj );
+	}
+
+	LuanJavaFunction(JavaMethod method,Object obj) {
+		this.method = method;
+		this.obj = obj;
+		this.rtnConverter = getRtnConverter(method);
+		this.takesLuaState = takesLuaState(method);
+		this.argConverters = getArgConverters(takesLuaState,method);
+		if( method.isVarArgs() ) {
+			Class<?>[] paramTypes = method.getParameterTypes();
+			this.varArgCls = paramTypes[paramTypes.length-1].getComponentType();
+		} else {
+			this.varArgCls = null;
+		}
+	}
+
+	public Class<?>[] getParameterTypes() {
+		return method.getParameterTypes();
+	}
+
+	@Override public Object[] call(LuanState lua,Object[] args) throws LuanException {
+		args = fixArgs(lua,args);
+		Object rtn;
+		try {
+			rtn = method.invoke(obj,args);
+		} catch(IllegalArgumentException e) {
+			checkArgs(lua,args);
+			throw e;
+		} catch(IllegalAccessException e) {
+			throw new RuntimeException(e);
+		} catch(InvocationTargetException e) {
+			Throwable cause = e.getCause();
+			if( cause instanceof Error )
+				throw (Error)cause;
+			if( cause instanceof RuntimeException )
+				throw (RuntimeException)cause;
+			if( cause instanceof LuanException )
+				throw (LuanException)cause;
+			throw new RuntimeException(e);
+		} catch(InstantiationException e) {
+			throw new RuntimeException(e);
+		}
+		return rtnConverter.convert(rtn);
+	}
+
+	private void checkArgs(LuanState lua,Object[] args) throws LuanException {
+		Class<?>[] a = getParameterTypes();
+		for( int i=0; i<a.length; i++ ) {
+			if( !a[i].isInstance(args[i]) ) {
+				String got = args[i].getClass().getName();
+				String expected = a[i].getName();
+				if( !takesLuaState )
+					i++;
+				throw new LuanException(lua,LuanElement.JAVA,"bad argument #"+i+" ("+expected+" expected, got "+got+")");
+			}
+		}
+	}
+
+	private Object[] fixArgs(LuanState lua,Object[] args) {
+		int n = argConverters.length;
+		Object[] rtn;
+		int start = 0;
+		if( !takesLuaState && varArgCls==null && args.length == n ) {
+			rtn = args;
+		} else {
+			if( takesLuaState )
+				n++;
+			rtn = new Object[n];
+			if( takesLuaState ) {
+				rtn[start++] = lua;
+			}
+			n = argConverters.length;
+			if( varArgCls != null ) {
+				n--;
+				if( args.length < argConverters.length ) {
+					rtn[rtn.length-1] = Array.newInstance(varArgCls,0);
+				} else {
+					int len = args.length - n;
+					Object varArgs = Array.newInstance(varArgCls,len);
+					ArgConverter ac = argConverters[n];
+					for( int i=0; i<len; i++ ) {
+						Array.set( varArgs, i, ac.convert(args[n+i]) );
+					}
+					rtn[rtn.length-1] = varArgs;
+				}
+			}
+			System.arraycopy(args,0,rtn,start,Math.min(args.length,n));
+		}
+		for( int i=0; i<n; i++ ) {
+			rtn[start+i] = argConverters[i].convert(rtn[start+i]);
+		}
+		return rtn;
+	}
+
+
+	private interface RtnConverter {
+		public Object[] convert(Object obj);
+	}
+
+	private static final RtnConverter RTN_EMPTY = new RtnConverter() {
+		public Object[] convert(Object obj) {
+			return EMPTY_RTN;
+		}
+	};
+
+	private static final RtnConverter RTN_ARRAY = new RtnConverter() {
+		public Object[] convert(Object obj) {
+			if( obj == null )
+				return NULL_RTN;
+			return (Object[])obj;
+		}
+	};
+
+	private static final RtnConverter RTN_ONE = new RtnConverter() {
+		public Object[] convert(Object obj) {
+			return new Object[]{obj};
+		}
+	};
+
+	private static final Object[] NULL_RTN = new Object[1];
+
+	private static final RtnConverter RTN_NUMBER_ARRAY = new RtnConverter() {
+		public Object[] convert(Object obj) {
+			if( obj == null )
+				return NULL_RTN;
+			Object[] rtn = new Object[Array.getLength(obj)];
+			for( int i=0; i<rtn.length; i++ ) {
+				rtn[i] = Array.get(obj,i);
+			}
+			return rtn;
+		}
+	};
+
+	private static RtnConverter getRtnConverter(JavaMethod m) {
+		Class<?> rtnType = m.getReturnType();
+		if( rtnType == Void.TYPE )
+			return RTN_EMPTY;
+		if( rtnType.isArray() ) {
+			rtnType = rtnType.getComponentType();
+			if( isNumber(rtnType) )
+				return RTN_NUMBER_ARRAY;
+			return RTN_ARRAY;
+		}
+		return RTN_ONE;
+	}
+
+	private static boolean isNumber(Class<?> rtnType) {
+		return rtnType == Byte.TYPE
+			|| rtnType == Short.TYPE
+			|| rtnType == Integer.TYPE
+			|| rtnType == Long.TYPE
+			|| rtnType == Float.TYPE
+			|| rtnType == Double.TYPE
+		;
+	}
+
+	private interface ArgConverter {
+		public Object convert(Object obj);
+	}
+
+	private static final ArgConverter ARG_SAME = new ArgConverter() {
+		public Object convert(Object obj) {
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_DOUBLE = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof Double )
+				return obj;
+			if( obj instanceof Number ) {
+				Number n = (Number)obj;
+				return n.doubleValue();
+			}
+			if( obj instanceof String ) {
+				String s = (String)obj;
+				try {
+					return Double.valueOf(s);
+				} catch(NumberFormatException e) {}
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_FLOAT = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof Float )
+				return obj;
+			if( obj instanceof Number ) {
+				Number n = (Number)obj;
+				float r = n.floatValue();
+				if( r==n.doubleValue() )
+					return r;
+			}
+			if( obj instanceof String ) {
+				String s = (String)obj;
+				try {
+					return Float.valueOf(s);
+				} catch(NumberFormatException e) {}
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_LONG = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof Long )
+				return obj;
+			if( obj instanceof Number ) {
+				Number n = (Number)obj;
+				long r = n.longValue();
+				if( r==n.doubleValue() )
+					return r;
+			}
+			else if( obj instanceof String ) {
+				String s = (String)obj;
+				try {
+					return Long.valueOf(s);
+				} catch(NumberFormatException e) {}
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_INTEGER = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof Integer )
+				return obj;
+			if( obj instanceof Number ) {
+				Number n = (Number)obj;
+				int r = n.intValue();
+				if( r==n.doubleValue() )
+					return r;
+			}
+			else if( obj instanceof String ) {
+				String s = (String)obj;
+				try {
+					return Integer.valueOf(s);
+				} catch(NumberFormatException e) {}
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_SHORT = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof Short )
+				return obj;
+			if( obj instanceof Number ) {
+				Number n = (Number)obj;
+				short r = n.shortValue();
+				if( r==n.doubleValue() )
+					return r;
+			}
+			else if( obj instanceof String ) {
+				String s = (String)obj;
+				try {
+					return Short.valueOf(s);
+				} catch(NumberFormatException e) {}
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_BYTE = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof Byte )
+				return obj;
+			if( obj instanceof Number ) {
+				Number n = (Number)obj;
+				byte r = n.byteValue();
+				if( r==n.doubleValue() )
+					return r;
+			}
+			else if( obj instanceof String ) {
+				String s = (String)obj;
+				try {
+					return Byte.valueOf(s);
+				} catch(NumberFormatException e) {}
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_TABLE = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof List ) {
+				@SuppressWarnings("unchecked")
+				List<Object> list = (List<Object>)obj;
+				return new LuanTable(list);
+			}
+			if( obj instanceof Map ) {
+				@SuppressWarnings("unchecked")
+				Map<Object,Object> map = (Map<Object,Object>)obj;
+				return new LuanTable(map);
+			}
+			if( obj instanceof Set ) {
+				@SuppressWarnings("unchecked")
+				Set<Object> set = (Set<Object>)obj;
+				return new LuanTable(set);
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_MAP = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof LuanTable ) {
+				LuanTable t = (LuanTable)obj;
+				return t.asMap();
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_LIST = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof LuanTable ) {
+				LuanTable t = (LuanTable)obj;
+				if( t.isList() )
+					return t.asList();
+			}
+			return obj;
+		}
+	};
+
+	private static final ArgConverter ARG_SET = new ArgConverter() {
+		public Object convert(Object obj) {
+			if( obj instanceof LuanTable ) {
+				LuanTable t = (LuanTable)obj;
+				if( t.isSet() )
+					return t.asSet();
+			}
+			return obj;
+		}
+	};
+
+	private static boolean takesLuaState(JavaMethod m) {
+		Class<?>[] paramTypes = m.getParameterTypes();
+		return paramTypes.length > 0 && paramTypes[0].equals(LuanState.class);
+	}
+
+	private static ArgConverter[] getArgConverters(boolean takesLuaState,JavaMethod m) {
+		final boolean isVarArgs = m.isVarArgs();
+		Class<?>[] paramTypes = m.getParameterTypes();
+		if( takesLuaState ) {
+			Class<?>[] t = new Class<?>[paramTypes.length-1];
+			System.arraycopy(paramTypes,1,t,0,t.length);
+			paramTypes = t;
+		}
+		ArgConverter[] a = new ArgConverter[paramTypes.length];
+		for( int i=0; i<a.length; i++ ) {
+			Class<?> paramType = paramTypes[i];
+			if( isVarArgs && i == a.length-1 )
+				paramType = paramType.getComponentType();
+			a[i] = getArgConverter(paramType);
+		}
+		return a;
+	}
+
+	private static ArgConverter getArgConverter(Class<?> cls) {
+		if( cls == Double.TYPE || cls.equals(Double.class) )
+			return ARG_DOUBLE;
+		if( cls == Float.TYPE || cls.equals(Float.class) )
+			return ARG_FLOAT;
+		if( cls == Long.TYPE || cls.equals(Long.class) )
+			return ARG_LONG;
+		if( cls == Integer.TYPE || cls.equals(Integer.class) )
+			return ARG_INTEGER;
+		if( cls == Short.TYPE || cls.equals(Short.class) )
+			return ARG_SHORT;
+		if( cls == Byte.TYPE || cls.equals(Byte.class) )
+			return ARG_BYTE;
+		if( cls.equals(LuanTable.class) )
+			return ARG_TABLE;
+		if( cls.equals(Map.class) )
+			return ARG_MAP;
+		if( cls.equals(List.class) )
+			return ARG_LIST;
+		if( cls.equals(Set.class) )
+			return ARG_SET;
+		return ARG_SAME;
+	}
+
+
+
+	private static abstract class JavaMethod {
+		abstract boolean isVarArgs();
+		abstract Class<?>[] getParameterTypes();
+		abstract Object invoke(Object obj,Object... args)
+			throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, InstantiationException;
+		abstract Class<?> getReturnType();
+	
+		static JavaMethod of(final Method m) {
+			return new JavaMethod() {
+				@Override boolean isVarArgs() {
+					return m.isVarArgs();
+				}
+				@Override Class<?>[] getParameterTypes() {
+					return m.getParameterTypes();
+				}
+				@Override Object invoke(Object obj,Object... args)
+					throws IllegalAccessException, IllegalArgumentException, InvocationTargetException
+				{
+					return m.invoke(obj,args);
+				}
+				@Override Class<?> getReturnType() {
+					return m.getReturnType();
+				}
+				@Override public String toString() {
+					return m.toString();
+				}
+			};
+		}
+	
+		static JavaMethod of(final Constructor c) {
+			return new JavaMethod() {
+				@Override boolean isVarArgs() {
+					return c.isVarArgs();
+				}
+				@Override Class<?>[] getParameterTypes() {
+					return c.getParameterTypes();
+				}
+				@Override Object invoke(Object obj,Object... args)
+					throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, InstantiationException
+				{
+					return c.newInstance(args);
+				}
+				@Override Class<?> getReturnType() {
+					return c.getDeclaringClass();
+				}
+				@Override public String toString() {
+					return c.toString();
+				}
+			};
+		}
+	
+	}
+
+}