org.joor

Class Reflect

java.lang.Object

org.joor.Reflect

public class Reflect
extends Object

A wrapper for an Object or Class upon which reflective calls can be made.

An example of using Reflect is

 // Static import all reflection methods to decrease verbosity
 import static org.joor.Reflect.*;

 // Wrap an Object / Class / class name with the on() method:
 on("java.lang.String")
 // Invoke constructors using the create() method:
 .create("Hello World")
 // Invoke methods using the call() method:
 .call("toString")
 // Retrieve the wrapped object
 

Author:

Lukas Eder, Irek Matysiewicz, Thomas Darimont

Method Summary

Modifier and Type	Method and Description
static <T extends AccessibleObject> T	accessible(T accessible) Conveniently render an AccessibleObject accessible.
<P> P	as(Class<P> proxyType) Create a proxy for the wrapped object allowing to typesafely invoke methods on it using a custom interface.
<P> P	as(Class<P> proxyType, Class<?>... additionalInterfaces) Create a proxy for the wrapped object allowing to typesafely invoke methods on it using a custom interface.
Reflect	call(String name) Call a method by its name.
Reflect	call(String name, Object... args) Call a method by its name.
static Reflect	compile(String name, String content) Compile a class at runtime and reflect on it.
static Reflect	compile(String name, String content, CompileOptions options) Compile a class at runtime and reflect on it.
Reflect	create() Call a constructor.
Reflect	create(Object... args) Call a constructor.
boolean	equals(Object obj)
Reflect	field(String name) Get a wrapped field.
Map<String,Reflect>	fields() Get a Map containing field names and wrapped values for the fields' values.
<T> T	get() Get the wrapped object
<T> T	get(String name) Get a field value.
int	hashCode()
static <T> T	initValue(Class<T> type) Get the initialisation or default value for any given type.
static Reflect	on(Class<?> clazz) Deprecated. [#78] 0.9.11, use onClass(Class) instead.
static Reflect	on(Object object) Wrap an object.
static Reflect	on(String name) Deprecated. [#78] 0.9.11, use onClass(String) instead.
static Reflect	on(String name, ClassLoader classLoader) Deprecated. [#78] 0.9.11, use onClass(String, ClassLoader) instead.
static Reflect	onClass(Class<?> clazz) Wrap a class.
static Reflect	onClass(String name) Wrap a class name.
static Reflect	onClass(String name, ClassLoader classLoader) Wrap a class name, loading it via a given class loader.
static void	process(String name, String content) Annotation-process a class at runtime.
static void	process(String name, String content, CompileOptions options) Annotation-process a class at runtime.
Reflect	set(String name, Object value) Set a field value.
String	toString()
Class<?>	type() Get the type of the wrapped object.
static <T> Class<T>	wrapper(Class<T> type) Get a wrapper type for a primitive type, or the argument type itself, if it is not a primitive type.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

compile

public static Reflect compile(String name,
                              String content)
                       throws ReflectException

Compile a class at runtime and reflect on it.

For example:

 Supplier<String> supplier = Reflect.compile("org.joor.Test", """
   package org.joor;
   class Test implements java.util.function.Supplier<String> {
     public String get() {
       return "Hello World!";
     }
   }
   """).create().get();
 

Parameters:

name - The qualified class name

content - The source code for the class

Returns:

A wrapped Class

Throws:

ReflectException - if anything went wrong compiling the class.

compile

public static Reflect compile(String name,
                              String content,
                              CompileOptions options)
                       throws ReflectException

Compile a class at runtime and reflect on it.

For example:

 Supplier<String> supplier = Reflect.compile("org.joor.Test", """
   package org.joor;
   class Test implements java.util.function.Supplier<String> {
     public String get() {
       return "Hello World!";
     }
   }
   """).create().get();
 

Parameters:

name - The qualified class name

content - The source code for the class

options - compiler options

Returns:

A wrapped Class

Throws:

ReflectException - if anything went wrong compiling the class.

process

public static void process(String name,
                           String content)
                    throws ReflectException

Annotation-process a class at runtime.

This works like compile(String, String), but adds the -proc:only CompileOptions and thus does not produce any compilation output.

For example:

 Supplier<String> supplier = Reflect.compile("org.joor.Test", """
   package org.joor;
   @MyAnnotation
   class Test implements java.util.function.Supplier<String> {
     public String get() {
       return "Hello World!";
     }
   }
   """).create().get();
 

Parameters:

name - The qualified class name

content - The source code for the class

Throws:

ReflectException - if anything went wrong compiling the class.

process

public static void process(String name,
                           String content,
                           CompileOptions options)
                    throws ReflectException

Annotation-process a class at runtime.

This works like compile(String, String), but adds the -proc:only CompileOptions and thus does not produce any compilation output.

For example:

 Supplier<String> supplier = Reflect.compile("org.joor.Test", """
   package org.joor;
   @MyAnnotation
   class Test implements java.util.function.Supplier<String> {
     public String get() {
       return "Hello World!";
     }
   }
   """).create().get();
 

Parameters:

name - The qualified class name

content - The source code for the class

options - compiler options

Throws:

ReflectException - if anything went wrong compiling the class.

on

@Deprecated
public static Reflect on(String name)
                               throws ReflectException

Deprecated. [#78] 0.9.11, use onClass(String) instead.

Wrap a class name.

This is the same as calling on(Class.forName(name))

Parameters:

name - A fully qualified class name

Returns:

A wrapped class object, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

See Also:

onClass(Class)

on

@Deprecated
public static Reflect on(String name,
                                      ClassLoader classLoader)
                               throws ReflectException

Deprecated. [#78] 0.9.11, use onClass(String, ClassLoader) instead.

Wrap a class name, loading it via a given class loader.

This is the same as calling on(Class.forName(name, classLoader))

Parameters:

name - A fully qualified class name.

classLoader - The class loader in whose context the class should be loaded.

Returns:

A wrapped class object, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

See Also:

onClass(Class)

on

@Deprecated
public static Reflect on(Class<?> clazz)

Deprecated. [#78] 0.9.11, use onClass(Class) instead.

Wrap a class.

Use this when you want to access static fields and methods on a Class object, or as a basis for constructing objects of that class using create(Object...)

Parameters:

clazz - The class to be wrapped

Returns:

A wrapped class object, to be used for further reflection.

onClass

public static Reflect onClass(String name)
                       throws ReflectException

Wrap a class name.

This is the same as calling onClass(Class.forName(name))

Parameters:

name - A fully qualified class name

Returns:

A wrapped class object, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

See Also:

onClass(Class)

onClass

public static Reflect onClass(String name,
                              ClassLoader classLoader)
                       throws ReflectException

Wrap a class name, loading it via a given class loader.

This is the same as calling onClass(Class.forName(name, classLoader))

Parameters:

name - A fully qualified class name.

classLoader - The class loader in whose context the class should be loaded.

Returns:

A wrapped class object, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

See Also:

onClass(Class)

onClass

public static Reflect onClass(Class<?> clazz)

Wrap a class.

Use this when you want to access static fields and methods on a Class object, or as a basis for constructing objects of that class using create(Object...)

Parameters:

clazz - The class to be wrapped

Returns:

A wrapped class object, to be used for further reflection.

on

public static Reflect on(Object object)

Wrap an object.

Use this when you want to access instance fields and methods on any Object

Parameters:

object - The object to be wrapped

Returns:

A wrapped object, to be used for further reflection.

initValue

public static <T> T initValue(Class<T> type)

Get the initialisation or default value for any given type.

This returns:

• null for reference types (including wrapper types)
• 0 for numeric primitive types (including char)
• false for the boolean primitive type.

accessible

public static <T extends AccessibleObject> T accessible(T accessible)

Conveniently render an AccessibleObject accessible.

To prevent SecurityException, this is only done if the argument object and its declaring class are non-public.

Parameters:

accessible - The object to render accessible

Returns:

The argument object rendered accessible

get

public <T> T get()

Get the wrapped object

Type Parameters:

T - A convenience generic parameter for automatic unsafe casting

set

public Reflect set(String name,
                   Object value)
            throws ReflectException

Set a field value.

This is roughly equivalent to Field.set(Object, Object). If the wrapped object is a Class, then this will set a value to a static member field. If the wrapped object is any other Object, then this will set a value to an instance member field.

This method is also capable of setting the value of (static) final fields. This may be convenient in situations where no SecurityManager is expected to prevent this, but do note that (especially static) final fields may already have been inlined by the javac and/or JIT and relevant code deleted from the runtime verison of your program, so setting these fields might not have any effect on your execution.

For restrictions of usage regarding setting values on final fields check: http://stackoverflow.com/questions/3301635/change-private-static-final-field-using-java-reflection ... and http://pveentjer.blogspot.co.at/2017/01/final-static-boolean-jit.html

Parameters:

name - The field name

value - The new field value

Returns:

The same wrapped object, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

get

public <T> T get(String name)
          throws ReflectException

Get a field value.

This is roughly equivalent to Field.get(Object). If the wrapped object is a Class, then this will get a value from a static member field. If the wrapped object is any other Object, then this will get a value from an instance member field.

If you want to "navigate" to a wrapped version of the field, use field(String) instead.

Parameters:

name - The field name

Returns:

The field value

Throws:

ReflectException - If any reflection exception occurred.

See Also:

field(String)

field

public Reflect field(String name)
              throws ReflectException

Get a wrapped field.

This is roughly equivalent to Field.get(Object). If the wrapped object is a Class, then this will wrap a static member field. If the wrapped object is any other Object, then this wrap an instance member field.

Parameters:

name - The field name

Returns:

The wrapped field

Throws:

ReflectException - If any reflection exception occurred.

fields

public Map<String,Reflect> fields()

Get a Map containing field names and wrapped values for the fields' values.

If the wrapped object is a Class, then this will return static fields. If the wrapped object is any other Object, then this will return instance fields.

These two calls are equivalent

 on(object).field("myField");
 on(object).fields().get("myField");
 

Returns:

A map containing field names and wrapped values.

call

public Reflect call(String name)
             throws ReflectException

Call a method by its name.

This is a convenience method for calling call(name, new Object[0])

Parameters:

name - The method name

Returns:

The wrapped method result or the same wrapped object if the method returns void, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

See Also:

call(String, Object...)

call

public Reflect call(String name,
                    Object... args)
             throws ReflectException

Call a method by its name.

This is roughly equivalent to Method.invoke(Object, Object...). If the wrapped object is a Class, then this will invoke a static method. If the wrapped object is any other Object, then this will invoke an instance method.

Just like Method.invoke(Object, Object...), this will try to wrap primitive types or unwrap primitive type wrappers if applicable. If several methods are applicable, by that rule, the first one encountered is called. i.e. when calling

 on(...).call("method", 1, 1);
 

The first of the following methods will be called:

 public void method(int param1, Integer param2);
 public void method(Integer param1, int param2);
 public void method(Number param1, Number param2);
 public void method(Number param1, Object param2);
 public void method(int param1, Object param2);
 

The best matching method is searched for with the following strategy:

1. public method with exact signature match in class hierarchy
2. non-public method with exact signature match on declaring class
3. public method with similar signature in class hierarchy
4. non-public method with similar signature on declaring class

Parameters:

name - The method name

args - The method arguments

Returns:

The wrapped method result or the same wrapped object if the method returns void, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

create

public Reflect create()
               throws ReflectException

Call a constructor.

This is a convenience method for calling create(new Object[0])

Returns:

The wrapped new object, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

See Also:

create(Object...)

create

public Reflect create(Object... args)
               throws ReflectException

Call a constructor.

This is roughly equivalent to Constructor.newInstance(Object...). If the wrapped object is a Class, then this will create a new object of that class. If the wrapped object is any other Object, then this will create a new object of the same type.

Just like Constructor.newInstance(Object...), this will try to wrap primitive types or unwrap primitive type wrappers if applicable. If several constructors are applicable, by that rule, the first one encountered is called. i.e. when calling

 on(C.class).create(1, 1);
 

The first of the following constructors will be applied:

 public C(int param1, Integer param2);
 public C(Integer param1, int param2);
 public C(Number param1, Number param2);
 public C(Number param1, Object param2);
 public C(int param1, Object param2);
 

Parameters:

args - The constructor arguments

Returns:

The wrapped new object, to be used for further reflection.

Throws:

ReflectException - If any reflection exception occurred.

as

public <P> P as(Class<P> proxyType)

Create a proxy for the wrapped object allowing to typesafely invoke methods on it using a custom interface.

Parameters:

proxyType - The interface type that is implemented by the proxy

Returns:

A proxy for the wrapped object

as

public <P> P as(Class<P> proxyType,
                Class<?>... additionalInterfaces)

Create a proxy for the wrapped object allowing to typesafely invoke methods on it using a custom interface.

Parameters:

proxyType - The interface type that is implemented by the proxy

additionalInterfaces - Additional interfaces that are implemented by the proxy

Returns:

A proxy for the wrapped object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

type

public Class<?> type()

Get the type of the wrapped object.

See Also:

Object.getClass()

wrapper

public static <T> Class<T> wrapper(Class<T> type)

Get a wrapper type for a primitive type, or the argument type itself, if it is not a primitive type.