public static void main(String[] args) {
if (args.length < 1) {
print(usage);
System.exit(0);
}
int lines = 0;
try {
Class<?> c = Class.forName(args[0]);
Method[] methods = c.getMethods();
Constructor[] ctors = c.getConstructors();
if (args.length == 1) {
for (Method method : methods) print(p.matcher(method.toString()).replaceAll(""));
for (Constructor ctor : ctors) print(p.matcher(ctor.toString()).replaceAll(""));
lines = methods.length + ctors.length;
} else {
for (Method method : methods)
if (method.toString().indexOf(args[1]) != -1) {
print(p.matcher(method.toString()).replaceAll(""));
lines++;
}
for (Constructor ctor : ctors)
if (ctor.toString().indexOf(args[1]) != -1) {
print(p.matcher(ctor.toString()).replaceAll(""));
lines++;
}
}
} catch (ClassNotFoundException e) {
print("No such class: " + e);
}
}
public static void main(String[] args) throws Exception {
Class clazz = Class.forName("com.mtl.spring.aop.helloworld.ArithmeticCalculatorLoggingProxy");
Object object = clazz.newInstance();
Method[] methods = clazz.getMethods();
StringBuffer sb = new StringBuffer();
sb.append("public class ")
.append(object.getClass().getCanonicalName())
.append("{\n")
.append("Object object ")
.append("\n");
Constructor[] constructors = clazz.getConstructors();
for (Constructor constructor : constructors) {
sb.append("\npublic ").append(constructor.getName()).append("(");
Class<?> p[] = constructor.getParameterTypes();
for (int j = 0; j < p.length; ++j) {
sb.append(p[j].getName() + " arg" + j);
if (j < p.length - 1) {
sb.delete(sb.length() - 1, sb.length());
}
}
sb.append(") {").append("\n\n");
sb.append("user.role.cotain(\"/admin/add\") {");
sb.append("\n System.currentTimeMillis();\n");
sb.append("this.object = ").append("arg0");
sb.append("}");
sb.append(" \nSystem.currentTimeMillis();\n");
sb.append("\n}");
}
sb.append("\n\n}");
System.out.println(sb);
for (Method method : methods) {
System.out.println(method.getName());
}
}
@SuppressWarnings("unchecked")
public static <T> Constructor<T> findConstructor(Class<T> type, Class<?>... paramTypes) {
Constructor<T>[] ctors = (Constructor<T>[]) type.getConstructors();
for (Constructor<T> ctor : ctors)
if (typesMatch(paramTypes, ctor.getParameterTypes())) return ctor;
return null;
}
/**
* すべてのメンバを表示する
*
* @param Class<?> c メンバを表示したいクラス型オブジェクト
*/
public static void printAllMembers(Class<?> c) {
System.out.println("クラス: ");
System.out.println(c);
System.out.println("フィールド: ");
Field[] declaredfields = c.getDeclaredFields();
Field[] fields = c.getFields();
ArrayList<Field> fieldList = new ArrayList<Field>(fields.length);
for (int i = 0; i < fields.length; i++) {
fieldList.add(fields[i]);
}
for (int i = 0; i < declaredfields.length; i++) {
if (!fieldList.contains(declaredfields[i])) {
fieldList.add(declaredfields[i]);
}
}
Field[] allFields = new Field[fieldList.size()];
for (int i = 0; i < allFields.length; i++) {
allFields[i] = fieldList.get(i);
}
printMembers(allFields);
System.out.println("コンストラクタ: ");
Constructor[] declaredconstructors = c.getDeclaredConstructors();
Constructor[] constructors = c.getConstructors();
ArrayList<Constructor> constructorList = new ArrayList<Constructor>(constructors.length);
for (int i = 0; i < constructors.length; i++) {
constructorList.add(constructors[i]);
}
for (int i = 0; i < declaredconstructors.length; i++) {
if (!constructorList.contains(declaredconstructors[i])) {
constructorList.add(declaredconstructors[i]);
}
}
Constructor[] allConstructors = new Constructor[constructorList.size()];
for (int i = 0; i < allConstructors.length; i++) {
allConstructors[i] = constructorList.get(i);
}
printMembers(allConstructors);
System.out.println("メソッド: ");
Method[] declaredmethods = c.getDeclaredMethods();
Method[] methods = c.getMethods();
ArrayList<Method> methodList = new ArrayList<Method>(methods.length);
for (int i = 0; i < methods.length; i++) {
methodList.add(methods[i]);
}
for (int i = 0; i < declaredmethods.length; i++) {
if (!methodList.contains(declaredmethods[i])) {
methodList.add(declaredmethods[i]);
}
}
Method[] allMethods = new Method[methodList.size()];
for (int i = 0; i < allMethods.length; i++) {
allMethods[i] = methodList.get(i);
}
printMembers(allMethods);
}
/**
* Return true if the type is not abstract and not an interface, and has a constructor annotated
* with {@link Inject} or its only constructor is the default constructor.
*
* @param type A class type
* @return True if the class type is instantiable
*/
public static boolean isInstantiable(Class<?> type) {
if (!Modifier.isAbstract(type.getModifiers()) && !type.isInterface()) {
// first check for a constructor annotated with @Inject,
// - this doesn't care how many we'll let the injector complain
// if there are more than one
for (Constructor<?> c : type.getDeclaredConstructors()) {
if (c.getAnnotation(Inject.class) != null) {
return true;
}
}
// check if we only have the public default constructor
if (type.getConstructors().length == 1
&& type.getConstructors()[0].getParameterTypes().length == 0) {
return true;
}
}
// no constructor available
return false;
}
private static boolean testConvexPolygonArch() {
boolean pass = true;
int test = 1;
int cnt;
ConvexPolygon poly;
Class cl;
Class[] temp;
System.out.println("ConvexPolygon architecture tests...");
Point a = new Point(7, 7);
Point b = new Point(0, 9);
Point c = new Point(-3, -5);
Point d = new Point(2, -6);
Point e = new Point(12, 0);
Point[] vertices = new Point[5];
vertices[0] = new Point(a);
vertices[1] = new Point(b);
vertices[2] = new Point(c);
vertices[3] = new Point(d);
vertices[4] = new Point(e);
poly = new ConvexPolygon(vertices, Color.cyan, false);
cl = poly.getClass();
pass &= test(cl.getConstructors().length == 1, test++);
pass &= test((temp = cl.getInterfaces()).length == 1, test++);
pass &= test(temp[0].getName().equals("Shape"), test++);
pass &= test(verifyEqualsMethodSignature(cl), test++);
cnt = countModifiers(cl.getDeclaredMethods(), Modifier.PUBLIC);
pass &= test(cnt == 9, test++);
cnt = cl.getFields().length;
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED);
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE);
pass &= test(cnt == 3, test++);
// Count and test number of of PACKAGE fields
cnt =
cl.getDeclaredFields().length
- countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE)
- countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED)
- countModifiers(cl.getDeclaredFields(), Modifier.PUBLIC);
pass &= test(cnt == 0, test++);
return pass;
}
@SuppressWarnings("unchecked")
private static <T> Constructor<T> getConstructor(Class<T> type) {
try {
return type.getDeclaredConstructor();
} catch (NoSuchMethodException e) {
// Ignore
}
Constructor[] constructors = type.getConstructors();
if (constructors.length != 1) {
throw new IllegalStateException("Class " + type + " should have a single public constructor");
}
return constructors[0];
}
@Override
public JvmConstructorDefinition resolveConstructorCall(
Resolver resolver, List<ActualParam> actualParams) {
List<JvmType> argsTypes = new ArrayList<>();
for (ActualParam actualParam : actualParams) {
if (actualParam.isNamed()) {
throw new SemanticErrorException(
actualParam, "It is not possible to use named parameters on Java classes");
} else {
argsTypes.add(actualParam.getValue().calcType(resolver).jvmType(resolver));
}
}
return ReflectionBasedMethodResolution.findConstructorAmong(
argsTypes, resolver, Arrays.asList(clazz.getConstructors()), this);
}
/**
* Finds the constructor of the given class that is compatible with the given arguments.
*
* @param type the class to find the constructor of
* @param args the arguments
* @return the constructor
*/
public static Constructor findConstructor(Class<?> type, Object[] args) {
outer:
for (Constructor constructor : type.getConstructors()) {
Class<?>[] paramTypes = constructor.getParameterTypes();
if (paramTypes.length != args.length) continue;
for (int i = 0; i < args.length; i++) {
Object arg = args[i];
if (arg != null && !paramTypes[i].isAssignableFrom(arg.getClass())) continue outer;
if (arg == null && paramTypes[i].isPrimitive()) continue outer;
}
return constructor;
}
throw new GrammarException(
"No constructor found for %s and the given %s arguments", type, args.length);
}
public static void main(String[] args) throws Exception {
Class<ClassTest> clazz = ClassTest.class;
System.out.println("=============================================");
Constructor[] ctors = clazz.getDeclaredConstructors();
System.out.println("classTest的全部构造器如下：");
for (Constructor c : ctors) {
System.out.println(c);
}
System.out.println("=============================================");
Constructor[] publicCtors = clazz.getConstructors();
System.out.println("ClassTest的全部public构造器如下：");
for (Constructor c : publicCtors) {
System.out.println(c);
}
System.out.println("=============================================");
Method[] mtds = clazz.getMethods();
System.out.println("ClassTest的全部public方法如下：");
for (Method md : mtds) {
System.out.println(md);
}
System.out.println("=============================================");
System.out.println("ClassTest带一个字符串参数的info方法为：" + clazz.getMethod("info", String.class));
Annotation[] ans = clazz.getAnnotations();
System.out.println("ClassTest的全部annotation为：");
for (Annotation an : ans) {
System.out.println(an);
}
System.out.println("该元素上的@SuppressWarnings注释为：" + clazz.getAnnotation(SuppressWarnings.class));
System.out.println("=============================================");
Class<?>[] inners = clazz.getDeclaredClasses();
System.out.println("ClassTest的全部内部类如下：");
for (Class c : inners) {
System.out.println(c);
}
System.out.println("=============================================");
Class inClazz = Class.forName("ClassTest$Inner");
System.out.println("inClazz对应的外部类为：" + inClazz.getDeclaringClass());
System.out.println("ClassTest的包为：" + clazz.getPackage());
System.out.println("ClassTest的父类：" + clazz.getSuperclass());
}
public void checkNoArgueMentConstructor(Class klass) {
Constructor[] constructor = klass.getConstructors();
boolean noArguement = false;
for (int j = 0; j < constructor.length; j++) {
Class<?>[] cklass = constructor[j].getParameterTypes();
String length = "" + cklass.length;
if (!length.isEmpty()) {
noArguement = true;
}
}
if (noArguement == true) {
textArea4.setText("this class does have a no arguement constructor.");
} else {
textArea4.setText("this class does not have a no arguement constructor.");
}
}
private static Object createArgumentPlaceholderForUnknownClass(
Class<?> clazz, Integer placeholderId) throws IllegalAccessException, InstantiationException {
FinalClassArgumentCreator<?> creator = FINAL_CLASS_ARGUMENT_CREATORS.get(clazz);
if (creator != null) return creator.createArgumentPlaceHolder(placeholderId);
for (Constructor constructor : clazz.getConstructors()) {
Class<?>[] params = constructor.getParameterTypes();
if (params.length != 1) continue;
try {
if (params[0] == String.class)
return constructor.newInstance(String.valueOf(placeholderId));
if (isNumericClass(params[0])) return constructor.newInstance(placeholderId);
} catch (IllegalAccessException e1) {
} catch (InvocationTargetException e2) {
}
}
return clazz.newInstance();
}
private static boolean testTriangleArch() {
boolean pass = true;
int test = 1;
int cnt;
Triangle tri;
Class cl;
Class[] temp;
System.out.println("Triangle architecture tests...");
Point a = new Point(0, 0);
Point b = new Point(3, 0);
Point c = new Point(0, 4);
tri = new Triangle(a, b, c, Color.cyan, false);
cl = tri.getClass();
pass &= test(cl.getConstructors().length == 1, test++);
pass &= test((temp = cl.getInterfaces()).length == 1, test++);
pass &= test(temp[0].getName().equals("Shape"), test++);
pass &= test(verifyEqualsMethodSignature(cl), test++);
cnt = countModifiers(cl.getDeclaredMethods(), Modifier.PUBLIC);
pass &= test(cnt == 13, test++);
cnt = cl.getFields().length;
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED);
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE);
pass &= test(cnt == 5, test++);
// Count and test number of of PACKAGE fields
cnt =
cl.getDeclaredFields().length
- countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE)
- countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED)
- countModifiers(cl.getDeclaredFields(), Modifier.PUBLIC);
pass &= test(cnt == 0, test++);
return pass;
}
public ConstructorArgumentConverter(Class<T> clazz, Object... arguments) {
for (Constructor<?> c : clazz.getConstructors()) {
if (isCompatible(c, arguments)) {
this.constructor = (Constructor<T>) c;
break;
}
}
if (constructor == null)
throw new IntrospectionException(
"Unable to find a constructor of "
+ clazz.getName()
+ " compatible with the given arguments");
if (arguments != null)
for (Object argument : arguments) {
argumentConverters.add(new ArgumentConverter<F, Object>(argument));
}
}
public static void printConstructors(Class<?> c) {
display2.append("コンストラクタ\r\n");
Constructor[] declaredconstructors = c.getDeclaredConstructors();
Constructor[] constructors = c.getConstructors();
ArrayList<Constructor> constructorList = new ArrayList<Constructor>(constructors.length);
for (int i = 0; i < constructors.length; i++) {
constructorList.add(constructors[i]);
}
for (int i = 0; i < declaredconstructors.length; i++) {
if (!constructorList.contains(declaredconstructors[i])) {
constructorList.add(declaredconstructors[i]);
}
}
Constructor[] allConstructors = new Constructor[constructorList.size()];
for (int i = 0; i < allConstructors.length; i++) {
allConstructors[i] = constructorList.get(i);
}
printMembers(allConstructors);
}
private static boolean testCircleArch() {
boolean pass = true;
int test = 1;
int cnt;
Circle circle;
Class cl;
Class[] temp;
System.out.println("Circle architecture tests...");
circle = new Circle(5.6789, new Point(-99, 66), Color.cyan, false);
cl = circle.getClass();
pass &= test(cl.getConstructors().length == 1, test++);
pass &= test((temp = cl.getInterfaces()).length == 1, test++);
pass &= test(temp[0].getName().equals("Shape"), test++);
pass &= test(verifyEqualsMethodSignature(cl), test++);
cnt = countModifiers(cl.getDeclaredMethods(), Modifier.PUBLIC);
pass &= test(cnt == 10, test++);
cnt = cl.getFields().length;
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED);
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE);
pass &= test(cnt == 4, test++);
// Count and test number of of PACKAGE fields
cnt =
cl.getDeclaredFields().length
- countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE)
- countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED)
- countModifiers(cl.getDeclaredFields(), Modifier.PUBLIC);
pass &= test(cnt == 0, test++);
return pass;
}
public static void printConstructors(AClass aClass) {
Class c = aClass.getClass();
// 获取指定类的类名
String className = c.getName();
try {
// 获取指定类的构造方法
Constructor[] theConstructors = c.getConstructors();
for (int i = 0; i < theConstructors.length; i++) {
// 获取指定构造方法的参数的集合
Class[] parameterTypes = theConstructors[i].getParameterTypes();
System.out.print(className + "(");
for (int j = 0; j < parameterTypes.length; j++)
System.out.print(parameterTypes[j].getName() + " ");
System.out.println(")");
}
} catch (Exception e) {
e.printStackTrace();
}
}
private static boolean testCanvasArch() {
boolean pass = true;
int test = 1;
int cnt;
Canvas canvas;
Class cl;
Class[] temp;
System.out.println("Canvas architecture tests...");
canvas = new Canvas();
cl = canvas.getClass();
pass &= test(cl.getConstructors().length == 1, test++);
cnt = countModifiers(cl.getDeclaredMethods(), Modifier.PUBLIC);
pass &= test(cnt == 10, test++);
cnt = cl.getFields().length;
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED);
pass &= test(cnt == 0, test++);
cnt = countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE);
pass &= test(cnt == 1, test++);
// Count and test number of of PACKAGE fields
cnt =
cl.getDeclaredFields().length
- countModifiers(cl.getDeclaredFields(), Modifier.PRIVATE)
- countModifiers(cl.getDeclaredFields(), Modifier.PROTECTED)
- countModifiers(cl.getDeclaredFields(), Modifier.PUBLIC);
pass &= test(cnt == 0, test++);
return pass;
}
/** Reflect operations demo */
public static void reflect(Object obj) {
// `cls用于描述对象所属的类`
Class cls = obj.getClass();
print("Class Name: " + cls.getCanonicalName());
// `fields包含对象的所有属性`
Field[] fields = cls.getDeclaredFields();
print("List of fields:");
for (Field f : fields) {
print(String.format("%30s %15s", f.getType(), f.getName()));
}
// `methods包含对象的所有方法`
Method[] methods = cls.getDeclaredMethods();
print("List of methods:");
for (Method m : methods)
print(
String.format(
"%30s %15s %30s",
m.getReturnType(), m.getName(), Arrays.toString(m.getParameterTypes())));
Constructor[] constructors = cls.getConstructors();
print("List of contructors:");
for (Constructor c : constructors)
print(String.format("%30s %15s", c.getName(), Arrays.toString(c.getParameterTypes())));
}
public static byte[] createAdapterCode(
ObjToIntMap functionNames,
String adapterName,
Class<?> superClass,
Class<?>[] interfaces,
String scriptClassName) {
ClassFileWriter cfw = new ClassFileWriter(adapterName, superClass.getName(), "<adapter>");
cfw.addField(
"factory",
"Laurora/javascript/ContextFactory;",
(short) (ClassFileWriter.ACC_PUBLIC | ClassFileWriter.ACC_FINAL));
cfw.addField(
"delegee",
"Laurora/javascript/Scriptable;",
(short) (ClassFileWriter.ACC_PUBLIC | ClassFileWriter.ACC_FINAL));
cfw.addField(
"self",
"Laurora/javascript/Scriptable;",
(short) (ClassFileWriter.ACC_PUBLIC | ClassFileWriter.ACC_FINAL));
int interfacesCount = interfaces == null ? 0 : interfaces.length;
for (int i = 0; i < interfacesCount; i++) {
if (interfaces[i] != null) cfw.addInterface(interfaces[i].getName());
}
String superName = superClass.getName().replace('.', '/');
Constructor<?>[] ctors = superClass.getConstructors();
for (Constructor<?> ctor : ctors) {
generateCtor(cfw, adapterName, superName, ctor);
}
generateSerialCtor(cfw, adapterName, superName);
if (scriptClassName != null) {
generateEmptyCtor(cfw, adapterName, superName, scriptClassName);
}
ObjToIntMap generatedOverrides = new ObjToIntMap();
ObjToIntMap generatedMethods = new ObjToIntMap();
// generate methods to satisfy all specified interfaces.
for (int i = 0; i < interfacesCount; i++) {
Method[] methods = interfaces[i].getMethods();
for (int j = 0; j < methods.length; j++) {
Method method = methods[j];
int mods = method.getModifiers();
if (Modifier.isStatic(mods) || Modifier.isFinal(mods)) {
continue;
}
String methodName = method.getName();
Class<?>[] argTypes = method.getParameterTypes();
if (!functionNames.has(methodName)) {
try {
superClass.getMethod(methodName, argTypes);
// The class we're extending implements this method and
// the JavaScript object doesn't have an override. See
// bug 61226.
continue;
} catch (NoSuchMethodException e) {
// Not implemented by superclass; fall through
}
}
// make sure to generate only one instance of a particular
// method/signature.
String methodSignature = getMethodSignature(method, argTypes);
String methodKey = methodName + methodSignature;
if (!generatedOverrides.has(methodKey)) {
generateMethod(cfw, adapterName, methodName, argTypes, method.getReturnType(), true);
generatedOverrides.put(methodKey, 0);
generatedMethods.put(methodName, 0);
}
}
}
// Now, go through the superclass's methods, checking for abstract
// methods or additional methods to override.
// generate any additional overrides that the object might contain.
Method[] methods = getOverridableMethods(superClass);
for (int j = 0; j < methods.length; j++) {
Method method = methods[j];
int mods = method.getModifiers();
// if a method is marked abstract, must implement it or the
// resulting class won't be instantiable. otherwise, if the object
// has a property of the same name, then an override is intended.
boolean isAbstractMethod = Modifier.isAbstract(mods);
String methodName = method.getName();
if (isAbstractMethod || functionNames.has(methodName)) {
// make sure to generate only one instance of a particular
// method/signature.
Class<?>[] argTypes = method.getParameterTypes();
String methodSignature = getMethodSignature(method, argTypes);
String methodKey = methodName + methodSignature;
if (!generatedOverrides.has(methodKey)) {
generateMethod(cfw, adapterName, methodName, argTypes, method.getReturnType(), true);
generatedOverrides.put(methodKey, 0);
generatedMethods.put(methodName, 0);
// if a method was overridden, generate a "super$method"
// which lets the delegate call the superclass' version.
if (!isAbstractMethod) {
generateSuper(
cfw,
adapterName,
superName,
methodName,
methodSignature,
argTypes,
method.getReturnType());
}
}
}
}
// Generate Java methods for remaining properties that are not
// overrides.
ObjToIntMap.Iterator iter = new ObjToIntMap.Iterator(functionNames);
for (iter.start(); !iter.done(); iter.next()) {
String functionName = (String) iter.getKey();
if (generatedMethods.has(functionName)) continue;
int length = iter.getValue();
Class<?>[] parms = new Class[length];
for (int k = 0; k < length; k++) parms[k] = ScriptRuntime.ObjectClass;
generateMethod(cfw, adapterName, functionName, parms, ScriptRuntime.ObjectClass, false);
}
return cfw.toByteArray();
}
public static void main(String[] args) {
// Obtain the class object if we know the name of the class
Class rental = RentCar.class;
try {
// get the absolute name of the class
String rentalClassPackage = rental.getName();
System.out.println("Class Name is: " + rentalClassPackage);
// get the simple name of the class (without package info)
String rentalClassNoPackage = rental.getSimpleName();
System.out.println("Class Name without package is: " + rentalClassNoPackage);
// get the package name of the class
Package rentalPackage = rental.getPackage();
System.out.println("Package Name is: " + rentalPackage);
// get all the constructors of the class
Constructor[] constructors = rental.getConstructors();
System.out.println("Constructors are: " + Arrays.toString(constructors));
// get constructor with specific argument
Constructor constructor = rental.getConstructor(Integer.TYPE);
// initializing an object of the RentCar class
RentCar rent = (RentCar) constructor.newInstance(455);
// get all methods of the class including declared methods of
// superclasses
// in that case, superclass of RentCar is the class java.lang.Object
Method[] allmethods = rental.getMethods();
System.out.println("Methods are: " + Arrays.toString(allmethods));
for (Method method : allmethods) {
System.out.println("method = " + method.getName());
}
// get all methods declared in the class
// but excludes inherited methods.
Method[] declaredMethods = rental.getDeclaredMethods();
System.out.println("Declared Methods are: " + Arrays.toString(declaredMethods));
for (Method dmethod : declaredMethods) {
System.out.println("method = " + dmethod.getName());
}
// get method with specific name and parameters
Method oneMethod = rental.getMethod("computeRentalCost", new Class[] {Integer.TYPE});
System.out.println("Method is: " + oneMethod);
// call computeRentalCost method with parameter int
oneMethod.invoke(rent, 4);
// get all the parameters of computeRentalCost
Class[] parameterTypes = oneMethod.getParameterTypes();
System.out.println(
"Parameter types of computeRentalCost() are: " + Arrays.toString(parameterTypes));
// get the return type of computeRentalCost
Class returnType = oneMethod.getReturnType();
System.out.println("Return type is: " + returnType);
// gets all the public member fields of the class RentCar
Field[] fields = rental.getFields();
System.out.println("Public Fields are: ");
for (Field oneField : fields) {
// get public field name
Field field = rental.getField(oneField.getName());
String fieldname = field.getName();
System.out.println("Fieldname is: " + fieldname);
// get public field type
Object fieldType = field.getType();
System.out.println("Type of field " + fieldname + " is: " + fieldType);
// get public field value
Object value = field.get(rent);
System.out.println("Value of field " + fieldname + " is: " + value);
}
// How to access private member fields of the class
// getDeclaredField() returns the private field
Field privateField = RentCar.class.getDeclaredField("type");
String name = privateField.getName();
System.out.println("One private Fieldname is: " + name);
// makes this private field instance accessible
// for reflection use only, not normal code
privateField.setAccessible(true);
// get the value of this private field
String fieldValue = (String) privateField.get(rent);
System.out.println("fieldValue = " + fieldValue);
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
@SuppressWarnings({"unchecked", "rawtypes"})
public static <T> T newInstance(Class<T> type, boolean strict, Object... parameters) {
if (parameters.length == 0) return newInstanceFromDefaultConstructor(type);
Constructor<T> constructorToUse = null;
try {
Constructor<T>[] constructors = (Constructor<T>[]) type.getConstructors();
List<Constructor<T>> candidates = new ArrayList<Constructor<T>>(constructors.length);
int paramCount = parameters.length;
for (Constructor<T> constructor : constructors)
if (constructor.getParameterTypes().length == paramCount) candidates.add(constructor);
if (candidates.size() == 1) constructorToUse = candidates.get(0);
else if (candidates.size() == 0)
throw new ConfigurationError(
"No constructor with " + paramCount + " parameters found for " + type);
else {
// there are several candidates - find the first one with matching types
Class<?>[] paramTypes = new Class[parameters.length];
for (int i = 0; i < parameters.length; i++) paramTypes[i] = parameters[i].getClass();
for (Constructor c : type.getConstructors()) {
if (typesMatch(c.getParameterTypes(), paramTypes)) {
constructorToUse = c;
break;
}
}
// there is no ideal match
if (constructorToUse == null) {
if (strict)
throw new NoSuchMethodException(
"No appropriate constructor found: "
+ type
+ '('
+ ArrayFormat.format(", ", paramTypes)
+ ')');
Exception mostRecentException = null;
for (Constructor<T> candidate : candidates) {
try {
return newInstance(candidate, strict, parameters);
} catch (Exception e) {
mostRecentException = e;
logger.warn("Exception in constructor call: " + candidate, e);
continue; // ignore exception and try next constructor
}
}
// no constructor could be called without exception
String errMsg =
(mostRecentException != null
? "None of these constructors could be called without exception: "
+ candidates
+ ", latest exception: "
+ mostRecentException
: type
+ " has no appropriate constructor for the arguments "
+ ArrayFormat.format(", ", parameters));
throw new ConfigurationError(errMsg);
}
}
if (!strict) parameters = convertArray(parameters, constructorToUse.getParameterTypes());
return newInstance(constructorToUse, parameters);
} catch (SecurityException e) {
throw ExceptionMapper.configurationException(e, constructorToUse);
} catch (NoSuchMethodException e) {
throw ExceptionMapper.configurationException(e, type);
}
}
