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- package de.klein5.TowerDefense.datawatcher;
- import java.lang.reflect.Constructor;
- import java.lang.reflect.Field;
- import java.lang.reflect.Method;
- import java.util.Arrays;
- import java.util.regex.Matcher;
- import java.util.regex.Pattern;
- import org.bukkit.Bukkit;
- /**
- * An utility class that simplifies reflection in Bukkit plugins.
- *
- * @author Kristian
- */
- public final class Reflection {
- /**
- * An interface for invoking a specific constructor.
- */
- public interface ConstructorInvoker {
- /**
- * Invoke a constructor for a specific class.
- *
- * @param arguments - the arguments to pass to the constructor.
- * @return The constructed object.
- */
- public Object invoke(Object... arguments);
- }
- /**
- * An interface for invoking a specific method.
- */
- public interface MethodInvoker {
- /**
- * Invoke a method on a specific target object.
- *
- * @param target - the target object, or NULL for a static method.
- * @param arguments - the arguments to pass to the method.
- * @return The return value, or NULL if is void.
- */
- public Object invoke(Object target, Object... arguments);
- }
- /**
- * An interface for retrieving the field content.
- *
- * @param <T> - field type.
- */
- public interface FieldAccessor<T> {
- /**
- * Retrieve the content of a field.
- *
- * @param target - the target object, or NULL for a static field.
- * @return The value of the field.
- */
- public T get(Object target);
- /**
- * Set the content of a field.
- *
- * @param target - the target object, or NULL for a static field.
- * @param value - the new value of the field.
- */
- public void set(Object target, Object value);
- /**
- * Determine if the given object has this field.
- *
- * @param target - the object to test.
- * @return TRUE if it does, FALSE otherwise.
- */
- public boolean hasField(Object target);
- }
- // Deduce the net.minecraft.server.v* package
- private static String OBC_PREFIX = Bukkit.getServer().getClass().getPackage().getName();
- private static String NMS_PREFIX = OBC_PREFIX.replace("org.bukkit.craftbukkit", "net.minecraft.server");
- private static String VERSION = OBC_PREFIX.replace("org.bukkit.craftbukkit", "").replace(".", "");
- // Variable replacement
- private static Pattern MATCH_VARIABLE = Pattern.compile("\\{([^\\}]+)\\}");
- private Reflection() {
- // Seal class
- }
- /**
- * Retrieve a field accessor for a specific field type and name.
- *
- * @param target - the target type.
- * @param name - the name of the field, or NULL to ignore.
- * @param fieldType - a compatible field type.
- * @return The field accessor.
- */
- public static <T> FieldAccessor<T> getField(Class<?> target, String name, Class<T> fieldType) {
- return getField(target, name, fieldType, 0);
- }
- /**
- * Retrieve a field accessor for a specific field type and name.
- *
- * @param className - lookup name of the class, see {@link #getClass(String)}.
- * @param name - the name of the field, or NULL to ignore.
- * @param fieldType - a compatible field type.
- * @return The field accessor.
- */
- public static <T> FieldAccessor<T> getField(String className, String name, Class<T> fieldType) {
- return getField(getClass(className), name, fieldType, 0);
- }
- /**
- * Retrieve a field accessor for a specific field type and name.
- *
- * @param target - the target type.
- * @param fieldType - a compatible field type.
- * @param index - the number of compatible fields to skip.
- * @return The field accessor.
- */
- public static <T> FieldAccessor<T> getField(Class<?> target, Class<T> fieldType, int index) {
- return getField(target, null, fieldType, index);
- }
- /**
- * Retrieve a field accessor for a specific field type and name.
- *
- * @param className - lookup name of the class, see {@link #getClass(String)}.
- * @param fieldType - a compatible field type.
- * @param index - the number of compatible fields to skip.
- * @return The field accessor.
- */
- public static <T> FieldAccessor<T> getField(String className, Class<T> fieldType, int index) {
- return getField(getClass(className), fieldType, index);
- }
- // Common method
- private static <T> FieldAccessor<T> getField(Class<?> target, String name, Class<T> fieldType, int index) {
- for (final Field field : target.getDeclaredFields()) {
- if ((name == null || field.getName().equals(name)) && fieldType.isAssignableFrom(field.getType()) && index-- <= 0) {
- field.setAccessible(true);
- // A function for retrieving a specific field value
- return new FieldAccessor<T>() {
- @Override
- @SuppressWarnings("unchecked")
- public T get(Object target) {
- try {
- return (T) field.get(target);
- } catch (IllegalAccessException e) {
- throw new RuntimeException("Cannot access reflection.", e);
- }
- }
- @Override
- public void set(Object target, Object value) {
- try {
- field.set(target, value);
- } catch (IllegalAccessException e) {
- throw new RuntimeException("Cannot access reflection.", e);
- }
- }
- @Override
- public boolean hasField(Object target) {
- // target instanceof DeclaringClass
- return field.getDeclaringClass().isAssignableFrom(target.getClass());
- }
- };
- }
- }
- // Search in parent classes
- if (target.getSuperclass() != null)
- return getField(target.getSuperclass(), name, fieldType, index);
- throw new IllegalArgumentException("Cannot find field with type " + fieldType);
- }
- /**
- * Search for the first publically and privately defined method of the given name and parameter count.
- *
- * @param className - lookup name of the class, see {@link #getClass(String)}.
- * @param methodName - the method name, or NULL to skip.
- * @param params - the expected parameters.
- * @return An object that invokes this specific method.
- * @throws IllegalStateException If we cannot find this method.
- */
- public static MethodInvoker getMethod(String className, String methodName, Class<?>... params) {
- return getTypedMethod(getClass(className), methodName, null, params);
- }
- /**
- * Search for the first publically and privately defined method of the given name and parameter count.
- *
- * @param clazz - a class to start with.
- * @param methodName - the method name, or NULL to skip.
- * @param params - the expected parameters.
- * @return An object that invokes this specific method.
- * @throws IllegalStateException If we cannot find this method.
- */
- public static MethodInvoker getMethod(Class<?> clazz, String methodName, Class<?>... params) {
- return getTypedMethod(clazz, methodName, null, params);
- }
- /**
- * Search for the first publically and privately defined method of the given name and parameter count.
- *
- * @param clazz - a class to start with.
- * @param methodName - the method name, or NULL to skip.
- * @param returnType - the expected return type, or NULL to ignore.
- * @param params - the expected parameters.
- * @return An object that invokes this specific method.
- * @throws IllegalStateException If we cannot find this method.
- */
- public static MethodInvoker getTypedMethod(Class<?> clazz, String methodName, Class<?> returnType, Class<?>... params) {
- for (final Method method : clazz.getDeclaredMethods()) {
- if ((methodName == null || method.getName().equals(methodName))
- && (returnType == null || method.getReturnType().equals(returnType))
- && Arrays.equals(method.getParameterTypes(), params)) {
- method.setAccessible(true);
- return new MethodInvoker() {
- @Override
- public Object invoke(Object target, Object... arguments) {
- try {
- return method.invoke(target, arguments);
- } catch (Exception e) {
- throw new RuntimeException("Cannot invoke method " + method, e);
- }
- }
- };
- }
- }
- // Search in every superclass
- if (clazz.getSuperclass() != null)
- return getMethod(clazz.getSuperclass(), methodName, params);
- throw new IllegalStateException(String.format("Unable to find method %s (%s).", methodName, Arrays.asList(params)));
- }
- /**
- * Search for the first publically and privately defined constructor of the given name and parameter count.
- *
- * @param className - lookup name of the class, see {@link #getClass(String)}.
- * @param params - the expected parameters.
- * @return An object that invokes this constructor.
- * @throws IllegalStateException If we cannot find this method.
- */
- public static ConstructorInvoker getConstructor(String className, Class<?>... params) {
- return getConstructor(getClass(className), params);
- }
- /**
- * Search for the first publically and privately defined constructor of the given name and parameter count.
- *
- * @param clazz - a class to start with.
- * @param params - the expected parameters.
- * @return An object that invokes this constructor.
- * @throws IllegalStateException If we cannot find this method.
- */
- public static ConstructorInvoker getConstructor(Class<?> clazz, Class<?>... params) {
- for (final Constructor<?> constructor : clazz.getDeclaredConstructors()) {
- if (Arrays.equals(constructor.getParameterTypes(), params)) {
- constructor.setAccessible(true);
- return new ConstructorInvoker() {
- @Override
- public Object invoke(Object... arguments) {
- try {
- return constructor.newInstance(arguments);
- } catch (Exception e) {
- throw new RuntimeException("Cannot invoke constructor " + constructor, e);
- }
- }
- };
- }
- }
- throw new IllegalStateException(String.format("Unable to find constructor for %s (%s).", clazz, Arrays.asList(params)));
- }
- /**
- * Retrieve a class from its full name, without knowing its type on compile time.
- * <p>
- * This is useful when looking up fields by a NMS or OBC type.
- * <p>
- *
- * @see {@link #getClass()} for more information.
- * @param lookupName - the class name with variables.
- * @return The class.
- */
- public static Class<Object> getUntypedClass(String lookupName) {
- @SuppressWarnings({ "rawtypes", "unchecked" })
- Class<Object> clazz = (Class) getClass(lookupName);
- return clazz;
- }
- /**
- * Retrieve a class from its full name.
- * <p>
- * Strings enclosed with curly brackets - such as {TEXT} - will be replaced according to the following table:
- * <p>
- * <table border="1">
- * <tr>
- * <th>Variable</th>
- * <th>Content</th>
- * </tr>
- * <tr>
- * <td>{nms}</td>
- * <td>Actual package name of net.minecraft.server.VERSION</td>
- * </tr>
- * <tr>
- * <td>{obc}</td>
- * <td>Actual pacakge name of org.bukkit.craftbukkit.VERSION</td>
- * </tr>
- * <tr>
- * <td>{version}</td>
- * <td>The current Minecraft package VERSION, if any.</td>
- * </tr>
- * </table>
- *
- * @param lookupName - the class name with variables.
- * @return The looked up class.
- * @throws IllegalArgumentException If a variable or class could not be found.
- */
- public static Class<?> getClass(String lookupName) {
- return getCanonicalClass(expandVariables(lookupName));
- }
- /**
- * Retrieve a class in the net.minecraft.server.VERSION.* package.
- *
- * @param name - the name of the class, excluding the package.
- * @throws IllegalArgumentException If the class doesn't exist.
- */
- public static Class<?> getMinecraftClass(String name) {
- return getCanonicalClass(NMS_PREFIX + "." + name);
- }
- /**
- * Retrieve a class in the org.bukkit.craftbukkit.VERSION.* package.
- *
- * @param name - the name of the class, excluding the package.
- * @throws IllegalArgumentException If the class doesn't exist.
- */
- public static Class<?> getCraftBukkitClass(String name) {
- return getCanonicalClass(OBC_PREFIX + "." + name);
- }
- /**
- * Retrieve a class by its canonical name.
- *
- * @param canonicalName - the canonical name.
- * @return The class.
- */
- private static Class<?> getCanonicalClass(String canonicalName) {
- try {
- return Class.forName(canonicalName);
- } catch (ClassNotFoundException e) {
- throw new IllegalArgumentException("Cannot find " + canonicalName, e);
- }
- }
- /**
- * Expand variables such as "{nms}" and "{obc}" to their corresponding packages.
- *
- * @param name - the full name of the class.
- * @return The expanded string.
- */
- private static String expandVariables(String name) {
- StringBuffer output = new StringBuffer();
- Matcher matcher = MATCH_VARIABLE.matcher(name);
- while (matcher.find()) {
- String variable = matcher.group(1);
- String replacement = "";
- // Expand all detected variables
- if ("nms".equalsIgnoreCase(variable))
- replacement = NMS_PREFIX;
- else if ("obc".equalsIgnoreCase(variable))
- replacement = OBC_PREFIX;
- else if ("version".equalsIgnoreCase(variable))
- replacement = VERSION;
- else
- throw new IllegalArgumentException("Unknown variable: " + variable);
- // Assume the expanded variables are all packages, and append a dot
- if (replacement.length() > 0 && matcher.end() < name.length() && name.charAt(matcher.end()) != '.')
- replacement += ".";
- matcher.appendReplacement(output, Matcher.quoteReplacement(replacement));
- }
- matcher.appendTail(output);
- return output.toString();
- }
- }
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