package com.rambo.tools;
import java.lang.reflect.*;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;
public abstract class ReflectionUtils {
private static final Pattern CGLIB_RENAMED_METHOD_PATTERN = Pattern.compile("CGLIB\\$(.+)\\$\\d+");
public static Field findField(Class<?> clazz, String name) {
return findField(clazz, name, null);
}
public static Field findField(Class<?> clazz, String name, Class<?> type) {
Class<?> searchType = clazz;
while (!Object.class.equals(searchType) && searchType != null) {
Field[] fields = searchType.getDeclaredFields();
for (Field field : fields) {
if ((name == null || name.equals(field.getName())) && (type == null || type.equals(field.getType()))) {
return field;
}
}
searchType = searchType.getSuperclass();
}
return null;
}
public static void setField(Field field, Object target, Object value) {
try {
field.set(target, value);
}
catch (IllegalAccessException ex) {
handleReflectionException(ex);
throw new IllegalStateException("Unexpected reflection exceptions - " + ex.getClass().getName() + ": "
+ ex.getMessage());
}
}
/**
* Get the field represented by the supplied {link Field field object} on the
* specified {link Object target object}. In accordance with {link Field#get(Object)}
* semantics, the returned value is automatically wrapped if the underlying field
* has a primitive type.
* <p>Thrown exceptions are handled via a call to {link #handleReflectionException(Exception)}.
* param field the field to get
* param target the target object from which to get the field
* return the field's current value
*/
public static Object getField(Field field, Object target) {
try {
return field.get(target);
}
catch (IllegalAccessException ex) {
handleReflectionException(ex);
throw new IllegalStateException(
"Unexpected reflection exceptions - " + ex.getClass().getName() + ": " + ex.getMessage());
}
}
/**
* Attempt to find a {link Method} on the supplied class with the supplied name
* and no parameters. Searches all superclasses up to <code>Object</code>.
* <p>Returns <code>null</code> if no {link Method} can be found.
* param clazz the class to introspect
* param name the name of the method
* return the Method object, or <code>null</code> if none found
*/
public static Method findMethod(Class<?> clazz, String name) {
return findMethod(clazz, name, new Class[0]);
}
/**
* Attempt to find a {link Method} on the supplied class with the supplied name
* and parameter types. Searches all superclasses up to <code>Object</code>.
* <p>Returns <code>null</code> if no {link Method} can be found.
* param clazz the class to introspect
* param name the name of the method
* param paramTypes the parameter types of the method
* (may be <code>null</code> to indicate any signature)
* return the Method object, or <code>null</code> if none found
*/
public static Method findMethod(Class<?> clazz, String name, Class<?>... paramTypes) {
Class<?> searchType = clazz;
while (searchType != null) {
Method[] methods = (searchType.isInterface() ? searchType.getMethods() : searchType.getDeclaredMethods());
for (Method method : methods) {
if (name.equals(method.getName())
&& (paramTypes == null || Arrays.equals(paramTypes, method.getParameterTypes()))) {
return method;
}
}
searchType = searchType.getSuperclass();
}
return null;
}
/**
* Invoke the specified {link Method} against the supplied target object with no arguments.
* The target object can be <code>null</code> when invoking a static {link Method}.
* <p>Thrown exceptions are handled via a call to {link #handleReflectionException}.
* param method the method to invoke
* param target the target object to invoke the method on
* return the invocation result, if any
* see #invokeMethod(java.lang.reflect.Method, Object, Object[])
*/
public static Object invokeMethod(Method method, Object target) {
return invokeMethod(method, target, new Object[0]);
}
/**
* Invoke the specified {link Method} against the supplied target object with the
* supplied arguments. The target object can be <code>null</code> when invoking a
* static {link Method}.
* <p>Thrown exceptions are handled via a call to {link #handleReflectionException}.
* param method the method to invoke
* param target the target object to invoke the method on
* param args the invocation arguments (may be <code>null</code>)
* return the invocation result, if any
*/
public static Object invokeMethod(Method method, Object target, Object... args) {
try {
return method.invoke(target, args);
}
catch (Exception ex) {
handleReflectionException(ex);
}
throw new IllegalStateException("Should never get here");
}
/**
* Invoke the specified JDBC API {link Method} against the supplied target
* object with no arguments.
* param method the method to invoke
* param target the target object to invoke the method on
* return the invocation result, if any
* throws SQLException the JDBC API SQLException to rethrow (if any)
* see #invokeJdbcMethod(java.lang.reflect.Method, Object, Object[])
*/
public static Object invokeJdbcMethod(Method method, Object target) throws SQLException {
return invokeJdbcMethod(method, target, new Object[0]);
}
/**
* Invoke the specified JDBC API {link Method} against the supplied target
* object with the supplied arguments.
* param method the method to invoke
* param target the target object to invoke the method on
* param args the invocation arguments (may be <code>null</code>)
* return the invocation result, if any
* throws SQLException the JDBC API SQLException to rethrow (if any)
* see #invokeMethod(java.lang.reflect.Method, Object, Object[])
*/
public static Object invokeJdbcMethod(Method method, Object target, Object... args) throws SQLException {
try {
return method.invoke(target, args);
}
catch (IllegalAccessException ex) {
handleReflectionException(ex);
}
catch (InvocationTargetException ex) {
if (ex.getTargetException() instanceof SQLException) {
throw (SQLException) ex.getTargetException();
}
handleInvocationTargetException(ex);
}
throw new IllegalStateException("Should never get here");
}
/**
* Handle the given reflection exceptions. Should only be called if no
* checked exceptions is expected to be thrown by the target method.
* <p>Throws the underlying RuntimeException or Error in case of an
* InvocationTargetException with such a root cause. Throws an
* IllegalStateException with an appropriate message else.
* param ex the reflection exceptions to handle
*/
public static void handleReflectionException(Exception ex) {
if (ex instanceof NoSuchMethodException) {
throw new IllegalStateException("Method not found: " + ex.getMessage());
}
if (ex instanceof IllegalAccessException) {
throw new IllegalStateException("Could not access method: " + ex.getMessage());
}
if (ex instanceof InvocationTargetException) {
handleInvocationTargetException((InvocationTargetException) ex);
}
if (ex instanceof RuntimeException) {
throw (RuntimeException) ex;
}
throw new UndeclaredThrowableException(ex);
}
/**
* Handle the given invocation target exceptions. Should only be called if no
* checked exceptions is expected to be thrown by the target method.
* <p>Throws the underlying RuntimeException or Error in case of such a root
* cause. Throws an IllegalStateException else.
* param ex the invocation target exceptions to handle
*/
public static void handleInvocationTargetException(InvocationTargetException ex) {
rethrowRuntimeException(ex.getTargetException());
}
/**
* Rethrow the given {link Throwable exceptions}, which is presumably the
* <em>target exceptions</em> of an {link InvocationTargetException}. Should
* only be called if no checked exceptions is expected to be thrown by the
* target method.
* <p>Rethrows the underlying exceptions cast to an {link RuntimeException} or
* {link Error} if appropriate; otherwise, throws an
* {link IllegalStateException}.
* param ex the exceptions to rethrow
* throws RuntimeException the rethrown exceptions
*/
public static void rethrowRuntimeException(Throwable ex) {
if (ex instanceof RuntimeException) {
throw (RuntimeException) ex;
}
if (ex instanceof Error) {
throw (Error) ex;
}
throw new UndeclaredThrowableException(ex);
}
/**
* Rethrow the given {link Throwable exceptions}, which is presumably the
* <em>target exceptions</em> of an {link InvocationTargetException}. Should
* only be called if no checked exceptions is expected to be thrown by the
* target method.
* <p>Rethrows the underlying exceptions cast to an {link Exception} or
* {link Error} if appropriate; otherwise, throws an
* {link IllegalStateException}.
* param ex the exceptions to rethrow
* throws Exception the rethrown exceptions (in case of a checked exceptions)
*/
public static void rethrowException(Throwable ex) throws Exception {
if (ex instanceof Exception) {
throw (Exception) ex;
}
if (ex instanceof Error) {
throw (Error) ex;
}
throw new UndeclaredThrowableException(ex);
}
/**
* Determine whether the given method explicitly declares the given
* exceptions or one of its superclasses, which means that an exceptions of
* that type can be propagated as-is within a reflective invocation.
* param method the declaring method
* param exceptionType the exceptions to throw
* return <code>true</code> if the exceptions can be thrown as-is;
* <code>false</code> if it needs to be wrapped
*/
public static boolean declaresException(Method method, Class<?> exceptionType) {
Class<?>[] declaredExceptions = method.getExceptionTypes();
for (Class<?> declaredException : declaredExceptions) {
if (declaredException.isAssignableFrom(exceptionType)) {
return true;
}
}
return false;
}
/**
* Determine whether the given field is a "public static final" constant.
* param field the field to check
*/
public static boolean isPublicStaticFinal(Field field) {
int modifiers = field.getModifiers();
return (Modifier.isPublic(modifiers) && Modifier.isStatic(modifiers) && Modifier.isFinal(modifiers));
}
/**
* Determine whether the given method is an "equals" method.
* see java.lang.Object#equals(Object)
*/
public static boolean isEqualsMethod(Method method) {
if (method == null || !method.getName().equals("equals")) {
return false;
}
Class<?>[] paramTypes = method.getParameterTypes();
return (paramTypes.length == 1 && paramTypes[0] == Object.class);
}
/**
* Determine whether the given method is a "hashCode" method.
* see java.lang.Object#hashCode()
*/
public static boolean isHashCodeMethod(Method method) {
return (method != null && method.getName().equals("hashCode") && method.getParameterTypes().length == 0);
}
/**
* Determine whether the given method is a "toString" method.
* see java.lang.Object#toString()
*/
public static boolean isToStringMethod(Method method) {
return (method != null && method.getName().equals("toString") && method.getParameterTypes().length == 0);
}
/**
* Determine whether the given method is originally declared by {link java.lang.Object}.
*/
public static boolean isObjectMethod(Method method) {
try {
Object.class.getDeclaredMethod(method.getName(), method.getParameterTypes());
return true;
} catch (SecurityException ex) {
return false;
} catch (NoSuchMethodException ex) {
return false;
}
}
/**
* Determine whether the given method is a CGLIB 'renamed' method, following
* the pattern "CGLIB$methodName$0".
* param renamedMethod the method to check
* see net.sf.cglib.proxy.Enhancer#rename
*/
public static boolean isCglibRenamedMethod(Method renamedMethod) {
return CGLIB_RENAMED_METHOD_PATTERN.matcher(renamedMethod.getName()).matches();
}
/**
* Make the given field accessible, explicitly setting it accessible if
* necessary. The <code>setAccessible(true)</code> method is only called
* when actually necessary, to avoid unnecessary conflicts with a JVM
* SecurityManager (if active).
* param field the field to make accessible
* see java.lang.reflect.Field#setAccessible
*/
public static void makeAccessible(Field field) {
if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) ||
Modifier.isFinal(field.getModifiers())) && !field.isAccessible()) {
field.setAccessible(true);
}
}
/**
* Make the given method accessible, explicitly setting it accessible if
* necessary. The <code>setAccessible(true)</code> method is only called
* when actually necessary, to avoid unnecessary conflicts with a JVM
* SecurityManager (if active).
* param method the method to make accessible
* see java.lang.reflect.Method#setAccessible
*/
public static void makeAccessible(Method method) {
if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers()))
&& !method.isAccessible()) {
method.setAccessible(true);
}
}
/**
* Make the given constructor accessible, explicitly setting it accessible
* if necessary. The <code>setAccessible(true)</code> method is only called
* when actually necessary, to avoid unnecessary conflicts with a JVM
* SecurityManager (if active).
* param ctor the constructor to make accessible
* see java.lang.reflect.Constructor#setAccessible
*/
public static void makeAccessible(Constructor<?> ctor) {
if ((!Modifier.isPublic(ctor.getModifiers()) || !Modifier.isPublic(ctor.getDeclaringClass().getModifiers()))
&& !ctor.isAccessible()) {
ctor.setAccessible(true);
}
}
/**
* Perform the given callback operation on all matching methods of the given
* class and superclasses.
* <p>The same named method occurring on subclass and superclass will appear
* twice, unless excluded by a {link MethodFilter}.
* param clazz class to start looking at
* param mc the callback to invoke for each method
* see #doWithMethods(Class, MethodCallback, MethodFilter)
*/
public static void doWithMethods(Class<?> clazz, MethodCallback mc) throws IllegalArgumentException {
doWithMethods(clazz, mc, null);
}
/**
* Perform the given callback operation on all matching methods of the given
* class and superclasses (or given interface and super-interfaces).
* <p>The same named method occurring on subclass and superclass will appear
* twice, unless excluded by the specified {link MethodFilter}.
* param clazz class to start looking at
* param mc the callback to invoke for each method
* param mf the filter that determines the methods to apply the callback to
*/
public static void doWithMethods(Class<?> clazz, MethodCallback mc, MethodFilter mf)
throws IllegalArgumentException {
// Keep backing up the inheritance hierarchy.
Method[] methods = clazz.getDeclaredMethods();
for (Method method : methods) {
if (mf != null && !mf.matches(method)) {
continue;
}
try {
mc.doWith(method);
}
catch (IllegalAccessException ex) {
throw new IllegalStateException("Shouldn't be illegal to access method '" + method.getName()
+ "': " + ex);
}
}
if (clazz.getSuperclass() != null) {
doWithMethods(clazz.getSuperclass(), mc, mf);
}
else if (clazz.isInterface()) {
for (Class<?> superIfc : clazz.getInterfaces()) {
doWithMethods(superIfc, mc, mf);
}
}
}
/**
* Get all declared methods on the leaf class and all superclasses. Leaf
* class methods are included first.
*/
public static Method[] getAllDeclaredMethods(Class<?> leafClass) throws IllegalArgumentException {
final List<Method> methods = new ArrayList<Method>(32);
doWithMethods(leafClass, new MethodCallback() {
public void doWith(Method method) {
methods.add(method);
}
});
return methods.toArray(new Method[methods.size()]);
}
/**
* Get the unique set of declared methods on the leaf class and all superclasses. Leaf
* class methods are included first and while traversing the superclass hierarchy any methods found
* with signatures matching a method already included are filtered out.
*/
public static Method[] getUniqueDeclaredMethods(Class<?> leafClass) throws IllegalArgumentException {
final List<Method> methods = new ArrayList<Method>(32);
doWithMethods(leafClass, new MethodCallback() {
public void doWith(Method method) {
boolean knownSignature = false;
Method methodBeingOverriddenWithCovariantReturnType = null;
for (Method existingMethod : methods) {
if (method.getName().equals(existingMethod.getName()) &&
Arrays.equals(method.getParameterTypes(), existingMethod.getParameterTypes())) {
// is this a covariant return type situation?
if (existingMethod.getReturnType() != method.getReturnType() &&
existingMethod.getReturnType().isAssignableFrom(method.getReturnType())) {
methodBeingOverriddenWithCovariantReturnType = existingMethod;
} else {
knownSignature = true;
}
break;
}
}
if (methodBeingOverriddenWithCovariantReturnType != null) {
methods.remove(methodBeingOverriddenWithCovariantReturnType);
}
if (!knownSignature && !isCglibRenamedMethod(method)) {
methods.add(method);
}
}
});
return methods.toArray(new Method[methods.size()]);
}
/**
* Invoke the given callback on all fields in the target class, going up the
* class hierarchy to get all declared fields.
* param clazz the target class to analyze
* param fc the callback to invoke for each field
*/
public static void doWithFields(Class<?> clazz, FieldCallback fc) throws IllegalArgumentException {
doWithFields(clazz, fc, null);
}
/**
* Invoke the given callback on all fields in the target class, going up the
* class hierarchy to get all declared fields.
* param clazz the target class to analyze
* param fc the callback to invoke for each field
* param ff the filter that determines the fields to apply the callback to
*/
public static void doWithFields(Class<?> clazz, FieldCallback fc, FieldFilter ff)
throws IllegalArgumentException {
// Keep backing up the inheritance hierarchy.
Class<?> targetClass = clazz;
do {
Field[] fields = targetClass.getDeclaredFields();
for (Field field : fields) {
// Skip static and final fields.
if (ff != null && !ff.matches(field)) {
continue;
}
try {
fc.doWith(field);
}
catch (IllegalAccessException ex) {
throw new IllegalStateException(
"Shouldn't be illegal to access field '" + field.getName() + "': " + ex);
}
}
targetClass = targetClass.getSuperclass();
}
while (targetClass != null && targetClass != Object.class);
}
/**
* Given the source object and the destination, which must be the same class
* or a subclass, copy all fields, including inherited fields. Designed to
* work on objects with public no-arg constructors.
* throws IllegalArgumentException if the arguments are incompatible
*/
public static void shallowCopyFieldState(final Object src, final Object dest) throws IllegalArgumentException {
if (src == null) {
throw new IllegalArgumentException("Source for field copy cannot be null");
}
if (dest == null) {
throw new IllegalArgumentException("Destination for field copy cannot be null");
}
if (!src.getClass().isAssignableFrom(dest.getClass())) {
throw new IllegalArgumentException("Destination class [" + dest.getClass().getName()
+ "] must be same or subclass as source class [" + src.getClass().getName() + "]");
}
doWithFields(src.getClass(), new FieldCallback() {
public void doWith(Field field) throws IllegalArgumentException, IllegalAccessException {
makeAccessible(field);
Object srcValue = field.get(src);
field.set(dest, srcValue);
}
}, COPYABLE_FIELDS);
}
/**
* Action to take on each method.
*/
public interface MethodCallback {
/**
* Perform an operation using the given method.
* param method the method to operate on
*/
void doWith(Method method) throws IllegalArgumentException, IllegalAccessException;
}
/**
* Callback optionally used to filter methods to be operated on by a method callback.
*/
public interface MethodFilter {
/**
* Determine whether the given method matches.
* param method the method to check
*/
boolean matches(Method method);
}
/**
* Callback interface invoked on each field in the hierarchy.
*/
public interface FieldCallback {
/**
* Perform an operation using the given field.
* param field the field to operate on
*/
void doWith(Field field) throws IllegalArgumentException, IllegalAccessException;
}
/**
* Callback optionally used to filter fields to be operated on by a field callback.
*/
public interface FieldFilter {
/**
* Determine whether the given field matches.
* param field the field to check
*/
boolean matches(Field field);
}
/**
* Pre-built FieldFilter that matches all non-static, non-final fields.
*/
public static FieldFilter COPYABLE_FIELDS = new FieldFilter() {
public boolean matches(Field field) {
return !(Modifier.isStatic(field.getModifiers()) || Modifier.isFinal(field.getModifiers()));
}
};
/**
* Pre-built MethodFilter that matches all non-bridge methods.
*/
public static MethodFilter NON_BRIDGED_METHODS = new MethodFilter() {
public boolean matches(Method method) {
return !method.isBridge();
}
};
/**
* Pre-built MethodFilter that matches all non-bridge methods
* which are not declared on <code>java.lang.Object</code>.
*/
public static MethodFilter USER_DECLARED_METHODS = new MethodFilter() {
public boolean matches(Method method) {
return (!method.isBridge() && method.getDeclaringClass() != Object.class);
}
};
}