/*
* $Id: JavaModule.java 76 2012-01-06 01:25:52Z andre@naef.com $
* See LICENSE.txt for license terms.
*/
package com.naef.jnlua;
import java.lang.reflect.Array;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import com.naef.jnlua.JavaReflector.Metamethod;
/**
* Provides the Java module for Lua. The Java module contains Java functions for
* using Java in Lua.
*/
public class JavaModule {
// -- Static
private static final JavaModule INSTANCE = new JavaModule();
private static final Map<String, Class<?>> PRIMITIVE_TYPES = new HashMap<String, Class<?>>();
static {
PRIMITIVE_TYPES.put("boolean", Boolean.TYPE);
PRIMITIVE_TYPES.put("byte", Byte.TYPE);
PRIMITIVE_TYPES.put("char", Character.TYPE);
PRIMITIVE_TYPES.put("double", Double.TYPE);
PRIMITIVE_TYPES.put("float", Float.TYPE);
PRIMITIVE_TYPES.put("int", Integer.TYPE);
PRIMITIVE_TYPES.put("long", Long.TYPE);
PRIMITIVE_TYPES.put("short", Short.TYPE);
PRIMITIVE_TYPES.put("void", Void.TYPE);
}
// -- State
private final NamedJavaFunction[] functions = { new Require(), new New(),
new InstanceOf(), new Cast(), new Proxy(), new Pairs(),
new IPairs(), new ToTable(), new Elements(), new Fields(),
new Methods(), new Properties() };
// -- Static methods
/**
* Returns the instance of the Java module.
*
* @return the instance
*/
public static JavaModule getInstance() {
return INSTANCE;
}
// -- Construction
/**
* Singleton.
*/
private JavaModule() {
}
// -- Operations
/**
* Opens this module in a Lua state. The method is invoked by
* {@link LuaState#openLibs()} or by
* {@link LuaState#openLib(com.naef.jnlua.LuaState.Library)} if
* {@link LuaState.Library#JAVA} is passed. The module is pushed onto the
* stack.
*
* @param luaState
* the Lua state to open in
*/
public void open(LuaState luaState) {
luaState.register("java", functions, true);
}
/**
* Returns a table-like Lua value for the specified map. The returned value
* corresponds to the return value of the <code>totable()</code> function
* provided by this Java module.
*
* @param map
* the map
* @return the table-like Lua value
*/
public TypedJavaObject toTable(Map<?, ?> map) {
return ToTable.toTable(map);
}
/**
* Returns a table-like Lua value for the specified list. The returned value
* corresponds to the return value of the <code>totable()</code> function
* provided by this Java module.
*
* @param list
* the list
* @return the table-like Lua value
*/
public TypedJavaObject toTable(List<?> list) {
return ToTable.toTable(list);
}
// -- Private methods
/**
* Loads a type. The named type is a primitive type or a class.
*/
private static Class<?> loadType(LuaState luaState, String typeName) {
Class<?> clazz;
if ((clazz = PRIMITIVE_TYPES.get(typeName)) != null) {
return clazz;
}
try {
clazz = luaState.getClassLoader().loadClass(typeName);
return clazz;
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
// -- Nested types
/**
* Imports a Java class into the Lua namespace. Returns the class and a
* status code. The status code indicates if the class was stored in the Lua
* namespace. Primitive types and classes without a package are not stored
* in the Lua namespace.
*/
private static class Require implements NamedJavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
// Check arguments
String className = luaState.checkString(1);
boolean doImport = luaState.toBoolean(2);
// Load
Class<?> clazz = loadType(luaState, className);
luaState.pushJavaObject(clazz);
// Import
if (doImport) {
luaState.rawGet(LuaState.REGISTRYINDEX, LuaState.RIDX_GLOBALS);
String name = clazz.getName();
int index = name.indexOf('.');
while (index >= 0) {
String part = name.substring(0, index);
luaState.getField(-1, part);
if (!luaState.isTable(-1)) {
luaState.pop(1);
luaState.newTable();
luaState.pushValue(-1);
luaState.setField(-3, part);
}
luaState.remove(-2);
name = name.substring(index + 1);
index = name.indexOf('.');
}
luaState.pushValue(-2);
luaState.setField(-2, name);
luaState.pop(1);
}
luaState.pushBoolean(doImport);
// Return
return 2;
}
@Override
public String getName() {
return "require";
}
}
/**
* Creates and returns a new Java object or array thereof. The first
* argument designates the type to instantiate, either as a class or a
* string. The remaining arguments are the dimensions.
*/
private static class New implements NamedJavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
// Find class
Class<?> clazz;
if (luaState.isJavaObject(1, Class.class)) {
clazz = luaState.checkJavaObject(1, Class.class);
} else {
String className = luaState.checkString(1);
clazz = loadType(luaState, className);
}
// Instantiate
Object object;
int dimensionCount = luaState.getTop() - 1;
switch (dimensionCount) {
case 0:
try {
object = clazz.newInstance();
} catch (InstantiationException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
break;
case 1:
object = Array.newInstance(clazz, luaState.checkInteger(2));
break;
default:
int[] dimensions = new int[dimensionCount];
for (int i = 0; i < dimensionCount; i++) {
dimensions[i] = luaState.checkInteger(i + 2);
}
object = Array.newInstance(clazz, dimensions);
}
// Return
luaState.pushJavaObject(object);
return 1;
}
@Override
public String getName() {
return "new";
}
}
/**
* Returns whether an object is an instance of a type. The object is given
* as the first argument. the type is given as the second argument, either
* as a class or as a type name.
*/
private static class InstanceOf implements NamedJavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
// Get the object
Object object = luaState.checkJavaObject(1, Object.class);
// Find class
Class<?> clazz;
if (luaState.isJavaObject(2, Class.class)) {
clazz = luaState.checkJavaObject(2, Class.class);
} else {
String className = luaState.checkString(2);
clazz = loadType(luaState, className);
}
// Type check
luaState.pushBoolean(clazz.isInstance(object));
return 1;
}
@Override
public String getName() {
return "instanceof";
}
}
/**
* Creates a typed Java object.
*/
private static class Cast implements NamedJavaFunction {
// -- NamedJavaFunction methods
@Override
public int invoke(LuaState luaState) {
// Find class
final Class<?> clazz;
if (luaState.isJavaObject(2, Class.class)) {
clazz = luaState.checkJavaObject(2, Class.class);
} else {
String className = luaState.checkString(2);
clazz = loadType(luaState, className);
}
// Get the object
final Object object = luaState.checkJavaObject(1, clazz);
// Push result
luaState.pushJavaObject(new TypedJavaObject() {
@Override
public Object getObject() {
return object;
}
@Override
public Class<?> getType() {
return clazz;
}
@Override
public boolean isStrong() {
return false;
}
});
return 1;
}
@Override
public String getName() {
return "cast";
}
}
/**
* Creates a dynamic proxy object the implements a set of Java interfaces in
* Lua.
*/
private static class Proxy implements NamedJavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
// Check table
luaState.checkType(1, LuaType.TABLE);
// Get interfaces
int interfaceCount = luaState.getTop() - 1;
luaState.checkArg(2, interfaceCount > 0, "no interface specified");
Class<?>[] interfaces = new Class<?>[interfaceCount];
for (int i = 0; i < interfaceCount; i++) {
if (luaState.isJavaObject(i + 2, Class.class)) {
interfaces[i] = luaState
.checkJavaObject(i + 2, Class.class);
} else {
String interfaceName = luaState.checkString(i + 2);
interfaces[i] = loadType(luaState, interfaceName);
}
}
// Create proxy
luaState.pushJavaObjectRaw(luaState.getProxy(1, interfaces));
return 1;
}
@Override
public String getName() {
return "proxy";
}
}
/**
* Provides the pairs iterator from the Java reflector.
*/
private static class Pairs implements NamedJavaFunction {
// -- NamedJavaFunction methods
@Override
public int invoke(LuaState luaState) {
luaState.checkArg(
1,
luaState.isJavaObjectRaw(1),
String.format("Java object expected, got %s",
luaState.typeName(1)));
JavaFunction metamethod = luaState.getMetamethod(
luaState.toJavaObjectRaw(1), Metamethod.PAIRS);
return metamethod.invoke(luaState);
}
@Override
public String getName() {
return "pairs";
}
}
/**
* Provides the ipairs iterator from the Java reflector.
*/
private static class IPairs implements NamedJavaFunction {
// -- NamedJavaFunction methods
@Override
public int invoke(LuaState luaState) {
luaState.checkArg(
1,
luaState.isJavaObjectRaw(1),
String.format("Java object expected, got %s",
luaState.typeName(1)));
JavaFunction metamethod = luaState.getMetamethod(
luaState.toJavaObjectRaw(1), Metamethod.IPAIRS);
return metamethod.invoke(luaState);
}
@Override
public String getName() {
return "ipairs";
}
}
/**
* Provides a wrapper object for table-like map and list access from Lua.
*/
private static class ToTable implements NamedJavaFunction {
// -- Static methods
/**
* Returns a table-like Lua value for the specified map.
*/
@SuppressWarnings("unchecked")
public static TypedJavaObject toTable(Map<?, ?> map) {
return new LuaMap((Map<Object, Object>) map);
}
/**
* Returns a table-list Lua value for the specified list.
*/
@SuppressWarnings("unchecked")
public static TypedJavaObject toTable(List<?> list) {
return new LuaList((List<Object>) list);
}
// -- JavaFunction methods
@SuppressWarnings("unchecked")
@Override
public int invoke(LuaState luaState) {
if (luaState.isJavaObject(1, Map.class)) {
Map<Object, Object> map = luaState.toJavaObject(1, Map.class);
luaState.pushJavaObject(new LuaMap(map));
} else if (luaState.isJavaObject(1, List.class)) {
List<Object> list = luaState.toJavaObject(1, List.class);
luaState.pushJavaObject(new LuaList(list));
} else {
luaState.checkArg(
1,
false,
String.format("expected map or list, got %s",
luaState.typeName(1)));
}
return 1;
}
@Override
public String getName() {
return "totable";
}
// -- Member types
/**
* Provides table-like access in Lua to a Java map.
*/
private static class LuaMap implements JavaReflector, TypedJavaObject {
// -- Static
private static final JavaFunction INDEX = new Index();
private static final JavaFunction NEW_INDEX = new NewIndex();
// -- State
private Map<Object, Object> map;
// -- Construction
/**
* Creates a new instance.
*/
public LuaMap(Map<Object, Object> map) {
this.map = map;
}
// -- Properties
/**
* Returns the map.
*/
public Map<Object, Object> getMap() {
return map;
}
// -- JavaReflector methods
@Override
public JavaFunction getMetamethod(Metamethod metamethod) {
switch (metamethod) {
case INDEX:
return INDEX;
case NEWINDEX:
return NEW_INDEX;
default:
return null;
}
}
// -- TypedJavaObject methods
@Override
public Object getObject() {
return map;
}
@Override
public Class<?> getType() {
return Map.class;
}
@Override
public boolean isStrong() {
return true;
}
// -- Member types
/**
* __index implementation for maps.
*/
private static class Index implements JavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
LuaMap luaMap = (LuaMap) luaState.toJavaObjectRaw(1);
Object key = luaState.toJavaObject(2, Object.class);
if (key == null) {
throw new LuaRuntimeException(String.format(
"attempt to read map with %s accessor",
luaState.typeName(2)));
}
luaState.pushJavaObject(luaMap.getMap().get(key));
return 1;
}
}
/**
* __newindex implementation for maps.
*/
private static class NewIndex implements JavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
LuaMap luaMap = (LuaMap) luaState.toJavaObjectRaw(1);
Object key = luaState.toJavaObject(2, Object.class);
if (key == null) {
throw new LuaRuntimeException(String.format(
"attempt to write map with %s accessor",
luaState.typeName(2)));
}
Object value = luaState.toJavaObject(3, Object.class);
if (value != null) {
luaMap.getMap().put(key, value);
} else {
luaMap.getMap().remove(key);
}
return 0;
}
}
}
/**
* Provides table-like access in Lua to a Java list.
*/
private static class LuaList implements JavaReflector, TypedJavaObject {
// -- Static
private static final JavaFunction INDEX = new Index();
private static final JavaFunction NEW_INDEX = new NewIndex();
private static final JavaFunction LENGTH = new Length();
// -- State
private List<Object> list;
// -- Construction
/**
* Creates a new instance.
*/
public LuaList(List<Object> list) {
this.list = list;
}
// -- Properties
/**
* Returns the map.
*/
public List<Object> getList() {
return list;
}
// -- JavaReflector methods
@Override
public JavaFunction getMetamethod(Metamethod metamethod) {
switch (metamethod) {
case INDEX:
return INDEX;
case NEWINDEX:
return NEW_INDEX;
case LEN:
return LENGTH;
default:
return null;
}
}
// -- TypedJavaObject methods
@Override
public Object getObject() {
return list;
}
@Override
public Class<?> getType() {
return List.class;
}
@Override
public boolean isStrong() {
return true;
}
// -- Member types
/**
* __index implementation for lists.
*/
private static class Index implements JavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
LuaList luaList = (LuaList) luaState.toJavaObjectRaw(1);
if (!luaState.isNumber(2)) {
throw new LuaRuntimeException(String.format(
"attempt to read list with %s accessor",
luaState.typeName(2)));
}
int index = luaState.toInteger(2);
luaState.pushJavaObject(luaList.getList().get(index - 1));
return 1;
}
}
/**
* __newindex implementation for lists.
*/
private static class NewIndex implements JavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
LuaList luaList = (LuaList) luaState.toJavaObjectRaw(1);
if (!luaState.isNumber(2)) {
throw new LuaRuntimeException(String.format(
"attempt to write list with %s accessor",
luaState.typeName(2)));
}
int index = luaState.toInteger(2);
Object value = luaState.toJavaObject(3, Object.class);
if (value != null) {
int size = luaList.getList().size();
if (index - 1 != size) {
luaList.getList().set(index - 1, value);
} else {
luaList.getList().add(value);
}
} else {
luaList.getList().remove(index - 1);
}
return 0;
}
}
/**
* __len implementation for lists.
*/
private static class Length implements JavaFunction {
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
LuaList luaList = (LuaList) luaState.toJavaObjectRaw(1);
luaState.pushInteger(luaList.getList().size());
return 1;
}
}
}
}
/**
* Provides an iterator for Iterable objects.
*/
private static class Elements implements NamedJavaFunction {
// -- NamedJavaFunction methods
@Override
public int invoke(LuaState luaState) {
Iterable<?> iterable = luaState.checkJavaObject(1, Iterable.class);
luaState.pushJavaObject(new ElementIterator(iterable.iterator()));
luaState.pushJavaObject(iterable);
luaState.pushNil();
return 3;
}
@Override
public String getName() {
return "elements";
}
// -- Member types
private static class ElementIterator implements JavaFunction {
// -- State
private Iterator<?> iterator;
// -- Construction
/**
* Creates a new instance.
*/
public ElementIterator(Iterator<?> iterator) {
this.iterator = iterator;
}
// -- JavaFunction methods
@Override
public int invoke(LuaState luaState) {
if (iterator.hasNext()) {
luaState.pushJavaObject(iterator.next());
} else {
luaState.pushNil();
}
return 1;
}
}
}
/**
* Provides an iterator for Java object fields.
*/
private static class Fields implements NamedJavaFunction {
// -- NamedJavaFunction methods
@Override
public int invoke(LuaState luaState) {
luaState.checkArg(
1,
luaState.isJavaObjectRaw(1),
String.format("expected Java object, got %s",
luaState.typeName(1)));
JavaFunction metamethod = luaState.getMetamethod(
luaState.toJavaObjectRaw(1), Metamethod.JAVAFIELDS);
return metamethod.invoke(luaState);
}
@Override
public String getName() {
return "fields";
}
}
/**
* Provides an iterator for Java methods.
*/
private static class Methods implements NamedJavaFunction {
// -- NamedJavaFunction methods
@Override
public int invoke(LuaState luaState) {
luaState.checkArg(
1,
luaState.isJavaObjectRaw(1),
String.format("expected Java object, got %s",
luaState.typeName(1)));
JavaFunction metamethod = luaState.getMetamethod(
luaState.toJavaObjectRaw(1), Metamethod.JAVAMETHODS);
return metamethod.invoke(luaState);
}
@Override
public String getName() {
return "methods";
}
}
/**
* Provides an iterator for Java object properties.
*/
private static class Properties implements NamedJavaFunction {
// -- NamedJavaFunction methods
@Override
public int invoke(LuaState luaState) {
luaState.checkArg(
1,
luaState.isJavaObjectRaw(1),
String.format("expected Java object, got %s",
luaState.typeName(1)));
JavaFunction metamethod = luaState.getMetamethod(
luaState.toJavaObjectRaw(1), Metamethod.JAVAPROPERTIES);
return metamethod.invoke(luaState);
}
@Override
public String getName() {
return "properties";
}
}
}