Package io.github.classgraph.utils

Class ReflectionUtils

java.lang.Object

io.github.classgraph.utils.ReflectionUtils

public class ReflectionUtils
extends Object

Reflection utility methods that can be used by ClassLoaderHandlers.

Constructor Summary

Constructors

Constructor	Description
ReflectionUtils()

Method Summary

Modifier and Type	Method	Description
static Class<?>	classForNameOrNull(String className)	Call Class.forName(className), but return null if any exception is thrown.
static Object	getFieldVal(Object obj, String fieldName, boolean throwException)	Get the value of the named field in the class of the given object or any of its superclasses.
static Object	getStaticFieldVal(Class<?> cls, String fieldName, boolean throwException)	Get the value of the named static field in the given class or any of its superclasses.
static Object	invokeDefaultMethod(Class<?> cls, String methodName, Class<?> returnType, ClassLoader classLoader, boolean throwException)	Invoke the named default interface method.
static Object	invokeMethod(Object obj, String methodName, boolean throwException)	Invoke the named method in the given object or its superclasses.
static Object	invokeMethod(Object obj, String methodName, Class<?> argType, Object arg, boolean throwException)	Invoke the named method in the given object or its superclasses.
static Object	invokeStaticMethod(Class<?> cls, String methodName, boolean throwException)	Invoke the named static method.
static Object	invokeStaticMethod(Class<?> cls, String methodName, Class<?> argType, Object arg, boolean throwException)	Invoke the named static method.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReflectionUtils

public ReflectionUtils()

Method Detail

getFieldVal

public static Object getFieldVal(Object obj,
                                 String fieldName,
                                 boolean throwException)
                          throws IllegalArgumentException

Get the value of the named field in the class of the given object or any of its superclasses. If an exception is thrown while trying to read the field, and throwException is true, then IllegalArgumentException is thrown wrapping the cause, otherwise this will return null. If passed a null object, returns null unless throwException is true, then throws IllegalArgumentException.

Parameters:

obj - The object.

fieldName - The field name.

throwException - If true, throw an exception if the field value could not be read.

Returns:

The field value.

Throws:

IllegalArgumentException - If the field value could not be read.

getStaticFieldVal

public static Object getStaticFieldVal(Class<?> cls,
                                       String fieldName,
                                       boolean throwException)
                                throws IllegalArgumentException

Get the value of the named static field in the given class or any of its superclasses. If an exception is thrown while trying to read the field value, and throwException is true, then IllegalArgumentException is thrown wrapping the cause, otherwise this will return null. If passed a null class reference, returns null unless throwException is true, then throws IllegalArgumentException.

Parameters:

cls - The class.

fieldName - The field name.

throwException - If true, throw an exception if the field value could not be read.

Returns:

The field value.

Throws:

IllegalArgumentException - If the field value could not be read.

invokeMethod

public static Object invokeMethod(Object obj,
                                  String methodName,
                                  boolean throwException)
                           throws IllegalArgumentException

Invoke the named method in the given object or its superclasses. If an exception is thrown while trying to call the method, and throwException is true, then IllegalArgumentException is thrown wrapping the cause, otherwise this will return null. If passed a null object, returns null unless throwException is true, then throws IllegalArgumentException.

Parameters:

obj - The object.

methodName - The method name.

throwException - If true, throw an exception if the field value could not be read.

Returns:

The field value.

Throws:

IllegalArgumentException - If the field value could not be read.

invokeMethod

public static Object invokeMethod(Object obj,
                                  String methodName,
                                  Class<?> argType,
                                  Object arg,
                                  boolean throwException)
                           throws IllegalArgumentException

Invoke the named method in the given object or its superclasses. If an exception is thrown while trying to call the method, and throwException is true, then IllegalArgumentException is thrown wrapping the cause, otherwise this will return null. If passed a null object, returns null unless throwException is true, then throws IllegalArgumentException.

Parameters:

obj - The object.

methodName - The method name.

argType - The type of the parameter.

arg - The argument value.

throwException - Whether to throw an exception on failure.

Returns:

The result of the method invocation.

Throws:

IllegalArgumentException - If the method could not be invoked.

invokeStaticMethod

public static Object invokeStaticMethod(Class<?> cls,
                                        String methodName,
                                        boolean throwException)
                                 throws IllegalArgumentException

Invoke the named static method. If an exception is thrown while trying to call the method, and throwException is true, then IllegalArgumentException is thrown wrapping the cause, otherwise this will return null. If passed a null class reference, returns null unless throwException is true, then throws IllegalArgumentException.

Parameters:

cls - The class.

methodName - The method name.

throwException - Whether to throw an exception on failure.

Returns:

The result of the method invocation.

Throws:

IllegalArgumentException - If the method could not be invoked.

invokeStaticMethod

public static Object invokeStaticMethod(Class<?> cls,
                                        String methodName,
                                        Class<?> argType,
                                        Object arg,
                                        boolean throwException)
                                 throws IllegalArgumentException

Invoke the named static method. If an exception is thrown while trying to call the method, and throwException is true, then IllegalArgumentException is thrown wrapping the cause, otherwise this will return null. If passed a null class reference, returns null unless throwException is true, then throws IllegalArgumentException.

Parameters:

cls - The class.

methodName - The method name.

argType - The type of the parameter.

arg - The argument value.

throwException - Whether to throw an exception on failure.

Returns:

The result of the method invocation.

Throws:

IllegalArgumentException - If the method could not be invoked.

invokeDefaultMethod

public static Object invokeDefaultMethod(Class<?> cls,
                                         String methodName,
                                         Class<?> returnType,
                                         ClassLoader classLoader,
                                         boolean throwException)
                                  throws IllegalArgumentException

Invoke the named default interface method. If an exception is thrown while trying to call the method, and throwException is true, then IllegalArgumentException is thrown wrapping the cause, otherwise this will return null. If passed a null class reference, returns null unless throwException is true, then throws IllegalArgumentException. Uses the solution in https://stackoverflow.com/a/49532492/3950982 TODO: This is not tested...

Parameters:

cls - The object.

methodName - The method name.

returnType - The return type of the method.

classLoader - The ClassLoader.

throwException - Whether to throw an exception on failure.

Returns:

The result of the method invokation.

Throws:

IllegalArgumentException - If the method could not be invoked.

classForNameOrNull

public static Class<?> classForNameOrNull(String className)

Call Class.forName(className), but return null if any exception is thrown.

Parameters:

className - The class name to load.

Returns:

The class of the requested name, or null if an exception was thrown while trying to load the class.