gololang

Class DynamicObject

java.lang.Object

gololang.DynamicObject

public final class DynamicObject
extends java.lang.Object

A dynamic object is an object whose properties can be dynamically added, changed and removed. Properties can be any object value or a function reference.

The methods plug and propertyMissing are left undocumented. They are being used by the Golo runtime to dispatch method invocations on dynamic objects.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.invoke.MethodHandle	DISPATCH_CALL
static java.lang.invoke.MethodHandle	DISPATCH_GET
static java.lang.invoke.MethodHandle	DISPATCH_SET

Constructor Summary

Constructors

Constructor and Description
DynamicObject()

Method Summary

Modifier and Type	Method and Description
DynamicObject	copy()
DynamicObject	define(java.lang.String name, java.lang.Object value) Defines a property.
static java.lang.Object	dispatchCall(java.lang.String property, java.lang.Object... args) Dispatch dynamic object "methods".
static java.lang.Object	dispatchGetterStyle(java.lang.String property, DynamicObject object) Dispatches getter-style dynamic object methods, i.e., methods with a receiver and no argument.
static java.lang.Object	dispatchSetterStyle(java.lang.String property, DynamicObject object, java.lang.Object arg) Dispatches setter-style dynamic object methods, i.e., methods with a receiver and exactly 1 argument.
DynamicObject	fallback(java.lang.Object value) Let the user define a fallback behavior.
DynamicObject	freeze() Freezes a dynamic object, meaning that its properties cannot be added, updated and removed anymore.
java.lang.Object	get(java.lang.String name)
boolean	hasMethod(java.lang.String method) Verify if a method is defined for the dynamic object.
java.lang.invoke.MethodHandle	invoker(java.lang.String property, java.lang.invoke.MethodType type) Gives an invoker method handle for a given property.
boolean	isFrozen() Tells whether the dynamic object is frozen or not.
DynamicObject	mixin(DynamicObject other) Mixes all properties from another dynamic object into this one, overwriting existing properties.
java.util.Set<java.util.Map.Entry<java.lang.String,java.lang.Object>>	properties()
DynamicObject	undefine(java.lang.String name) Removes a property.

Methods inherited from class java.lang.Object

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

Field Detail

DISPATCH_CALL

public static final java.lang.invoke.MethodHandle DISPATCH_CALL

DISPATCH_GET

public static final java.lang.invoke.MethodHandle DISPATCH_GET

DISPATCH_SET

public static final java.lang.invoke.MethodHandle DISPATCH_SET

Constructor Detail

DynamicObject

public DynamicObject()

Method Detail

define

public DynamicObject define(java.lang.String name,
                            java.lang.Object value)

Defines a property.

Parameters:

name - the property name.

value - the property value.

Returns:

the same dynamic object.

Throws:

java.lang.IllegalStateException - if the dynamic object is frozen.

properties

public java.util.Set<java.util.Map.Entry<java.lang.String,java.lang.Object>> properties()

Returns:

a view of all properties.

get

public java.lang.Object get(java.lang.String name)

Parameters:

name - the property name.

Returns:

the property value.

undefine

public DynamicObject undefine(java.lang.String name)

Removes a property.

Parameters:

name - the property name.

Returns:

the same dynamic object.

copy

public DynamicObject copy()

Returns:

a new dynamic object whose properties point to the same objects.

mixin

public DynamicObject mixin(DynamicObject other)

Mixes all properties from another dynamic object into this one, overwriting existing properties.

Parameters:

other - the dynamic object to mix the properties from.

Returns:

the same dynamic object.

freeze

public DynamicObject freeze()

Freezes a dynamic object, meaning that its properties cannot be added, updated and removed anymore.

Returns:

the same dynamic object.

isFrozen

public boolean isFrozen()

Tells whether the dynamic object is frozen or not.

Returns:

true if frozen, false otherwise.

dispatchCall

public static java.lang.Object dispatchCall(java.lang.String property,
                                            java.lang.Object... args)
                                     throws java.lang.Throwable

Dispatch dynamic object "methods". The receiver dynamic object is expected to be the first element of args.

Parameters:

property - the method property in the dynamic object.

args - the arguments.

Returns:

the return value.

Throws:

java.lang.Throwable - in case everything is wrong.

dispatchGetterStyle

public static java.lang.Object dispatchGetterStyle(java.lang.String property,
                                                   DynamicObject object)
                                            throws java.lang.Throwable

Dispatches getter-style dynamic object methods, i.e., methods with a receiver and no argument.

Parameters:

property - the method property in the dynamic object.

object - the receiver object.

Returns:

the return value.

Throws:

java.lang.Throwable - in case everything is wrong.

dispatchSetterStyle

public static java.lang.Object dispatchSetterStyle(java.lang.String property,
                                                   DynamicObject object,
                                                   java.lang.Object arg)
                                            throws java.lang.Throwable

Dispatches setter-style dynamic object methods, i.e., methods with a receiver and exactly 1 argument.

Parameters:

property - the method property in the dynamic object.

object - the receiver object.

arg - the arguments.

Returns:

the return value.

Throws:

java.lang.Throwable - in case everything is wrong.

invoker

public java.lang.invoke.MethodHandle invoker(java.lang.String property,
                                             java.lang.invoke.MethodType type)

Gives an invoker method handle for a given property.

While this method may be useful in itself, it is mostly relevant for the Golo runtime internals so as to allow calling "methods" on dynamic objects, as in:

 # obj is some dynamic object...
 obj: foo("bar")
 println(foo: bar())

 obj: define("plop", |this| -> "Plop!")
 println(obj: plop())
 

Parameters:

property - the name of a property.

type - the expected invoker type with at least one parameter (the dynamic object as a receiver).

Returns:

a method handle.

hasMethod

public boolean hasMethod(java.lang.String method)

Verify if a method is defined for the dynamic object.

Parameters:

method - the method name.

Returns:

true if method is defined, false otherwise.

fallback

public DynamicObject fallback(java.lang.Object value)

Let the user define a fallback behavior.

Parameters:

value - the fallback value

Returns:

the current object