com.cjcrafter.foliascheduler.util

Class ReflectionUtil

java.lang.Object

com.cjcrafter.foliascheduler.util.ReflectionUtil

public final class ReflectionUtil
extends java.lang.Object

A utility class that wraps the Java Reflection API and provides methods to access classes and constructors without having to handle checked exceptions.

This class delegates methods to the underlying Java Reflection API, but wraps checked exceptions in WrappedReflectiveOperationException. You can get the original exception by calling Throwable.getCause().

This class handles the remapping of class names, field names, and method names when running on Paper 1.20.5+. Because of the remapping, these methods will be even slower than the normal Java Reflection API. This means that you should be saving the results of these methods, typically in a static final field, to avoid the performance penalty of reflection.

Field Summary

Fields

Modifier and Type	Field and Description
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_FINAL
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_NOT_FINAL
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_NOT_PRIVATE
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_NOT_PUBLIC
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_NOT_STATIC
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_PRIVATE
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_PUBLIC
static @NotNull java.util.function.Predicate<java.lang.reflect.Member>	IS_STATIC

Method Summary

Modifier and Type	Method and Description
static <T> @NotNull java.lang.Class<T>	getClass(@NotNull java.lang.String className) Returns the Class object with the specified name.
static <T> @NotNull ConstructorInvoker<T>	getConstructor(@NotNull java.lang.Class<T> clazz, java.lang.Class<?>... parameterTypes) Returns the ConstructorInvoker for the specified constructor.
static <T> @NotNull java.lang.Class<T>	getCraftBukkitClass(@NotNull java.lang.String classPath) Returns the Class object from the org.bukkit.craftbukkit package with the specified relative path.
static @NotNull FieldAccessor	getField(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.Class<?> fieldType) Returns the FieldAccessor for the specified field.
static @NotNull FieldAccessor	getField(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.Class<?> fieldType, int index) Returns the FieldAccessor for the specified field.
static @NotNull FieldAccessor	getField(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.Class<?> fieldType, int index, @Nullable java.util.function.Predicate<? super java.lang.reflect.Field> predicate) Returns the FieldAccessor for the specified field.
static @NotNull FieldAccessor	getField(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.String fieldName) Returns the FieldAccessor for the specified field.
static @NotNull MethodInvoker	getMethod(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.Class<?> returnType, java.lang.Class<?>... parameterTypes) Returns the MethodInvoker for the specified method.
static @NotNull MethodInvoker	getMethod(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.Class<?> returnType, int index, java.lang.Class<?>... parameterTypes) Returns the MethodInvoker for the specified method.
static @NotNull MethodInvoker	getMethod(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.Class<?> returnType, int index, @Nullable java.util.function.Predicate<? super java.lang.reflect.Method> predicate, java.lang.Class<?>... parameterTypes) Returns the MethodInvoker for the specified method.
static @NotNull MethodInvoker	getMethod(@NotNull java.lang.Class<?> clazz, @NotNull java.lang.String methodName, java.lang.Class<?>... parameterTypes) Returns the MethodInvoker for the specified method.
static <T> @NotNull java.lang.Class<T>	getMinecraftClass(@NotNull java.lang.String packageName, @NotNull java.lang.String className) Returns the net.minecraft.server Class object with the specified name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

IS_PUBLIC

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_PUBLIC

IS_NOT_PUBLIC

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_NOT_PUBLIC

IS_PRIVATE

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_PRIVATE

IS_NOT_PRIVATE

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_NOT_PRIVATE

IS_STATIC

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_STATIC

IS_NOT_STATIC

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_NOT_STATIC

IS_FINAL

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_FINAL

IS_NOT_FINAL

@NotNull
public static final @NotNull java.util.function.Predicate<java.lang.reflect.Member> IS_NOT_FINAL

Method Detail

getClass

@NotNull
public static <T> @NotNull java.lang.Class<T> getClass(@NotNull
                                                                @NotNull java.lang.String className)

Returns the Class object with the specified name.

This method is a wrapper around Class.forName(String) that catches the checked exception and rethrows it as a WrappedReflectiveOperationException.

When running on Paper 1.20.5+, this method will remap the class name using the mappings built into the Paper jar.

Type Parameters:

T - the type of the class

Parameters:

className - the fully qualified name of the desired class

Returns:

the Class object for the class with the specified name

Throws:

WrappedReflectiveOperationException - if the class cannot be found

getMinecraftClass

@NotNull
public static <T> @NotNull java.lang.Class<T> getMinecraftClass(@NotNull
                                                                         @NotNull java.lang.String packageName,
                                                                         @NotNull
                                                                         @NotNull java.lang.String className)

Returns the net.minecraft.server Class object with the specified name. This method calls getClass(String) with the full class name constructed from the package name and class name.

We recommend using a mappings website to find the correct package and class name. Always use the Spigot mapped package and class name.

Type Parameters:

T - the type of the class

Parameters:

packageName - the name of the Spigot mapped mojang package, without the "net.minecraft." prefix (e.g. "world.entity.player")

className - the mojang mapped class name (e.g. "EntityPlayer")

Returns:

the Class object for the class with the specified name

Throws:

WrappedReflectiveOperationException - if the class cannot be found

getCraftBukkitClass

@NotNull
public static <T> @NotNull java.lang.Class<T> getCraftBukkitClass(@NotNull
                                                                           @NotNull java.lang.String classPath)

Returns the Class object from the org.bukkit.craftbukkit package with the specified relative path. This method calls getClass(String).

For example, to get the class org.bukkit.craftbukkit.v1_17_R1.entity.CraftPlayer, you would call getCraftBukkitClass("entity.CraftPlayer").

Type Parameters:

T - the type of the class

Parameters:

classPath - the relative path of the class, without the "org.bukkit.craftbukkit." prefix.

Returns:

the Class object for the class with the specified name

getField

@NotNull
public static @NotNull FieldAccessor getField(@NotNull
                                                       @NotNull java.lang.Class<?> clazz,
                                                       @NotNull
                                                       @NotNull java.lang.String fieldName)

Returns the FieldAccessor for the specified field.

Parameters:

clazz - The class that owns the field.

fieldName - The name of the field.

Returns:

The FieldAccessor for the field.

getField

@NotNull
public static @NotNull FieldAccessor getField(@NotNull
                                                       @NotNull java.lang.Class<?> clazz,
                                                       @NotNull
                                                       @NotNull java.lang.Class<?> fieldType)

Returns the FieldAccessor for the specified field. If no such field exists, an IllegalArgumentException is thrown.

Parameters:

clazz - The class that owns the field.

fieldType - The type of the field.

Returns:

The FieldAccessor for the field.

See Also:

getField(Class, Class, int, Predicate)

getField

@NotNull
public static @NotNull FieldAccessor getField(@NotNull
                                                       @NotNull java.lang.Class<?> clazz,
                                                       @NotNull
                                                       @NotNull java.lang.Class<?> fieldType,
                                                       int index)

Returns the FieldAccessor for the specified field. If no such field exists, an IllegalArgumentException is thrown.

Parameters:

clazz - The class that owns the field.

fieldType - The type of the field.

index - The index of the field to get (in case there are multiple fields of the same type).

Returns:

The FieldAccessor for the field.

See Also:

getField(Class, Class, int, Predicate)

getField

@NotNull
public static @NotNull FieldAccessor getField(@NotNull
                                                       @NotNull java.lang.Class<?> clazz,
                                                       @NotNull
                                                       @NotNull java.lang.Class<?> fieldType,
                                                       int index,
                                                       @Nullable
                                                       @Nullable java.util.function.Predicate<? super java.lang.reflect.Field> predicate)

Returns the FieldAccessor for the specified field. If no such field exists, an IllegalArgumentException is thrown.

This method can be used to get the nth field of a certain type in a class. For example, to get the 2nd non-static field of type int in a class, you would call getField(clazz, int.class, 2, IS_FIELD_NON_STATIC).

Parameters:

clazz - The class that owns the field.

fieldType - The type of the field.

index - The index of the field to get (in case there are multiple fields of the same type).

predicate - A predicate to filter the fields. If the predicate returns false, the field is skipped.

Returns:

The FieldAccessor for the field.

getMethod

@NotNull
public static @NotNull MethodInvoker getMethod(@NotNull
                                                        @NotNull java.lang.Class<?> clazz,
                                                        @NotNull
                                                        @NotNull java.lang.String methodName,
                                                        java.lang.Class<?>... parameterTypes)

Returns the MethodInvoker for the specified method.

Parameters:

clazz - The class that owns the method.

methodName - The name of the method.

parameterTypes - The parameter types of the method.

Returns:

The MethodInvoker for the method.

getMethod

@NotNull
public static @NotNull MethodInvoker getMethod(@NotNull
                                                        @NotNull java.lang.Class<?> clazz,
                                                        @NotNull
                                                        @NotNull java.lang.Class<?> returnType,
                                                        java.lang.Class<?>... parameterTypes)

Returns the MethodInvoker for the specified method. If no such method exists, an IllegalArgumentException is thrown.

Parameters:

clazz - The class that owns the method.

returnType - The return type of the method.

parameterTypes - The parameter types of the method.

Returns:

The MethodInvoker for the method.

See Also:

getMethod(Class, Class, int, Predicate, Class...)

getMethod

@NotNull
public static @NotNull MethodInvoker getMethod(@NotNull
                                                        @NotNull java.lang.Class<?> clazz,
                                                        @NotNull
                                                        @NotNull java.lang.Class<?> returnType,
                                                        int index,
                                                        java.lang.Class<?>... parameterTypes)

Returns the MethodInvoker for the specified method. If no such method exists, an IllegalArgumentException is thrown.

Parameters:

clazz - The class that owns the method.

returnType - The return type of the method.

index - The index of the method to get (in case there are multiple methods with the same return type).

parameterTypes - The parameter types of the method.

Returns:

The MethodInvoker for the method.

See Also:

getMethod(Class, Class, int, Predicate, Class...)

getMethod

@NotNull
public static @NotNull MethodInvoker getMethod(@NotNull
                                                        @NotNull java.lang.Class<?> clazz,
                                                        @NotNull
                                                        @NotNull java.lang.Class<?> returnType,
                                                        int index,
                                                        @Nullable
                                                        @Nullable java.util.function.Predicate<? super java.lang.reflect.Method> predicate,
                                                        java.lang.Class<?>... parameterTypes)

Returns the MethodInvoker for the specified method. If no such method exists, an IllegalArgumentException is thrown.

This method can be used to get the nth method of a certain return type in a class. For example, to get the 2nd method with return type void in a class, you would call getMethod(clazz, void.class, 2, null, parameterTypes).

Parameters:

clazz - The class that owns the method.

returnType - The return type of the method.

index - The index of the method to get (in case there are multiple methods with the same return type).

predicate - A predicate to filter the methods. If the predicate returns false, the method is skipped.

parameterTypes - The parameter types of the method.

Returns:

The MethodInvoker for the method.

getConstructor

@NotNull
public static <T> @NotNull ConstructorInvoker<T> getConstructor(@NotNull
                                                                         @NotNull java.lang.Class<T> clazz,
                                                                         java.lang.Class<?>... parameterTypes)

Returns the ConstructorInvoker for the specified constructor.

Type Parameters:

T - The type of the class.

Parameters:

clazz - The class that owns the constructor.

parameterTypes - The parameter types of the constructor.

Returns:

The ConstructorInvoker for the constructor.