org.mozilla.javascript
Class NativeJavaClass

java.lang.Object
  org.mozilla.javascript.NativeJavaObject
      org.mozilla.javascript.NativeJavaClass

All Implemented Interfaces:

java.io.Serializable, Callable, Function, Scriptable, Wrapper

public class NativeJavaClass
extends NativeJavaObject
implements Function

This class reflects Java classes into the JavaScript environment, mainly for constructors and static members. We lazily reflect properties, and currently do not guarantee that a single j.l.Class is only reflected once into the JS environment, although we should. The only known case where multiple reflections are possible occurs when a j.l.Class is wrapped as part of a method return or property access, rather than by walking the Packages/java tree.

Author:

Mike Shaver

See Also:

NativeJavaArray, NativeJavaObject, NativeJavaPackage, Serialized Form

Field Summary

Fields inherited from class org.mozilla.javascript.NativeJavaObject

isAdapter, javaObject, members, parent, prototype, staticType

Fields inherited from interface org.mozilla.javascript.Scriptable

NOT_FOUND

Constructor Summary

NativeJavaClass()

NativeJavaClass(Scriptable scope, java.lang.Class<?> cl)

NativeJavaClass(Scriptable scope, java.lang.Class<?> cl, boolean isAdapter)

Method Summary

java.lang.Object	call(Context cx, Scriptable scope, Scriptable thisObj, java.lang.Object[] args) Call the function.
Scriptable	construct(Context cx, Scriptable scope, java.lang.Object[] args) Call the function as a constructor.
java.lang.Object	get(java.lang.String name, Scriptable start) Get a named property from the object.
java.lang.String	getClassName() Get the name of the set of objects implemented by this Java class.
java.lang.Class<?>	getClassObject()
java.lang.Object	getDefaultValue(java.lang.Class<?> hint) Get the default value of the object with a given hint.
java.lang.Object[]	getIds() Get an array of property ids.
boolean	has(java.lang.String name, Scriptable start) Indicates whether or not a named property is defined in an object.
boolean	hasInstance(Scriptable value) Determines if prototype is a wrapped Java object and performs a Java "instanceof".
protected void	initMembers()
void	put(java.lang.String name, Scriptable start, java.lang.Object value) Sets a named property in this object.
java.lang.String	toString()

Methods inherited from class org.mozilla.javascript.NativeJavaObject

canConvert, coerceType, createInterfaceAdapter, delete, delete, get, getParentScope, getPrototype, has, put, setParentScope, setPrototype, unwrap, wrap

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.mozilla.javascript.Scriptable

delete, delete, get, getParentScope, getPrototype, has, put, setParentScope, setPrototype

Constructor Detail

NativeJavaClass

public NativeJavaClass()

NativeJavaClass

public NativeJavaClass(Scriptable scope,
                       java.lang.Class<?> cl)

NativeJavaClass

public NativeJavaClass(Scriptable scope,
                       java.lang.Class<?> cl,
                       boolean isAdapter)

Method Detail

initMembers

protected void initMembers()

Overrides:

initMembers in class NativeJavaObject

getClassName

public java.lang.String getClassName()

Description copied from interface: Scriptable

Get the name of the set of objects implemented by this Java class. This corresponds to the [[Class]] operation in ECMA and is used by Object.prototype.toString() in ECMA.

See ECMA 8.6.2 and 15.2.4.2.

Specified by:

getClassName in interface Scriptable

Overrides:

getClassName in class NativeJavaObject

has

public boolean has(java.lang.String name,
                   Scriptable start)

Description copied from interface: Scriptable

Indicates whether or not a named property is defined in an object. Does not traverse the prototype chain.

The property is specified by a String name as defined for the get method.

Specified by:

has in interface Scriptable

Overrides:

has in class NativeJavaObject

Parameters:

name - the name of the property

start - the object in which the lookup began

Returns:

true if and only if the named property is found in the object

See Also:

Scriptable.get(String, Scriptable), ScriptableObject.getProperty(Scriptable, String)

get

public java.lang.Object get(java.lang.String name,
                            Scriptable start)

Description copied from interface: Scriptable

Get a named property from the object. Looks property up in this object and returns the associated value if found. Returns NOT_FOUND if not found. Note that this method is not expected to traverse the prototype chain. This is different from the ECMA [[Get]] operation. Depending on the property selector, the runtime will call this method or the form of get that takes an integer:

JavaScript code	Java code
a.b	a.get("b", a)
a["foo"]	a.get("foo", a)
a[3]	a.get(3, a)
a["3"]	a.get(3, a)
a[3.0]	a.get(3, a)
a["3.0"]	a.get("3.0", a)
a[1.1]	a.get("1.1", a)
a[-4]	a.get(-4, a)

The values that may be returned are limited to the following:

• java.lang.Boolean objects
• java.lang.String objects
• java.lang.Number objects
• org.mozilla.javascript.Scriptable objects
• null
• The value returned by Context.getUndefinedValue()
• NOT_FOUND

Specified by:

get in interface Scriptable

Overrides:

get in class NativeJavaObject

Parameters:

name - the name of the property

start - the object in which the lookup began

Returns:

the value of the property (may be null), or NOT_FOUND

See Also:

Context.getUndefinedValue()

put

public void put(java.lang.String name,
                Scriptable start,
                java.lang.Object value)

Description copied from interface: Scriptable

Sets a named property in this object.

The property is specified by a string name as defined for get.

The possible values that may be passed in are as defined for get. A class that implements this method may choose to ignore calls to set certain properties, in which case those properties are effectively read-only.

For properties defined in a prototype chain, use putProperty in ScriptableObject.

Note that if a property a is defined in the prototype p of an object o, then evaluating o.a = 23 will cause set to be called on the prototype p with o as the start parameter. To preserve JavaScript semantics, it is the Scriptable object's responsibility to modify o.

This design allows properties to be defined in prototypes and implemented in terms of getters and setters of Java values without consuming slots in each instance.

The values that may be set are limited to the following:

• java.lang.Boolean objects
• java.lang.String objects
• java.lang.Number objects
• org.mozilla.javascript.Scriptable objects
• null
• The value returned by Context.getUndefinedValue()

Arbitrary Java objects may be wrapped in a Scriptable by first calling Context.toObject. This allows the property of a JavaScript object to contain an arbitrary Java object as a value.

Note that has will be called by the runtime first before set is called to determine in which object the property is defined. Note that this method is not expected to traverse the prototype chain, which is different from the ECMA [[Put]] operation.

Specified by:

put in interface Scriptable

Overrides:

put in class NativeJavaObject

Parameters:

name - the name of the property

start - the object whose property is being set

value - value to set the property to

See Also:

Scriptable.has(String, Scriptable), Scriptable.get(String, Scriptable), ScriptableObject.putProperty(Scriptable, String, Object), Context.toObject(Object, Scriptable)

getIds

public java.lang.Object[] getIds()

Description copied from interface: Scriptable

Get an array of property ids. Not all property ids need be returned. Those properties whose ids are not returned are considered non-enumerable.

Specified by:

getIds in interface Scriptable

Overrides:

getIds in class NativeJavaObject

Returns:

an array of Objects. Each entry in the array is either a java.lang.String or a java.lang.Number

getClassObject

public java.lang.Class<?> getClassObject()

getDefaultValue

public java.lang.Object getDefaultValue(java.lang.Class<?> hint)

Description copied from interface: Scriptable

Get the default value of the object with a given hint. The hints are String.class for type String, Number.class for type Number, Scriptable.class for type Object, and Boolean.class for type Boolean.

A hint of null means "no hint". See ECMA 8.6.2.6.

Specified by:

getDefaultValue in interface Scriptable

Overrides:

getDefaultValue in class NativeJavaObject

Parameters:

hint - the type hint

Returns:

the default value

call

public java.lang.Object call(Context cx,
                             Scriptable scope,
                             Scriptable thisObj,
                             java.lang.Object[] args)

Description copied from interface: Function

Call the function. Note that the array of arguments is not guaranteed to have length greater than 0.

Specified by:

call in interface Callable

Specified by:

call in interface Function

Parameters:

cx - the current Context for this thread

scope - the scope to execute the function relative to. This is set to the value returned by getParentScope() except when the function is called from a closure.

thisObj - the JavaScript this object

args - the array of arguments

Returns:

the result of the call

construct

public Scriptable construct(Context cx,
                            Scriptable scope,
                            java.lang.Object[] args)

Description copied from interface: Function

Call the function as a constructor. This method is invoked by the runtime in order to satisfy a use of the JavaScript new operator. This method is expected to create a new object and return it.

Specified by:

construct in interface Function

Parameters:

cx - the current Context for this thread

scope - an enclosing scope of the caller except when the function is called from a closure.

args - the array of arguments

Returns:

the allocated object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

hasInstance

public boolean hasInstance(Scriptable value)

Determines if prototype is a wrapped Java object and performs a Java "instanceof". Exception: if value is an instance of NativeJavaClass, it isn't considered an instance of the Java class; this forestalls any name conflicts between java.lang.Class's methods and the static methods exposed by a JavaNativeClass.

Specified by:

hasInstance in interface Scriptable

Overrides:

hasInstance in class NativeJavaObject

Parameters:

value - The value that appeared on the LHS of the instanceof operator

Returns:

an implementation dependent value