Class Delegator
- All Implemented Interfaces:
Callable
,Constructable
,Function
,Scriptable
,SymbolScriptable
- Direct Known Subclasses:
Synchronizer
A useful application is the implementation of interceptors, pre/post conditions, debugging.
- Author:
- Matthias Radestock
- See Also:
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Field Summary
Fields inherited from interface org.mozilla.javascript.Scriptable
NOT_FOUND
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Constructor Summary
ConstructorDescriptionCreate a Delegator prototype.Delegator
(Scriptable obj) Create a new Delegator that forwards requests to a delegee Scriptable object. -
Method Summary
Modifier and TypeMethodDescriptioncall
(Context cx, Scriptable scope, Scriptable thisObj, Object[] args) Call the function.construct
(Context cx, Scriptable scope, Object[] args) Note that if thedelegee
isnull
, this method creates a new instance of the Delegator itself rather than forwarding the call to thedelegee
.void
delete
(int index) Removes a property from this object.void
Removes a property from this object.void
Delete a property with the specified key.get
(int index, Scriptable start) Get a property from the object selected by an integral index.get
(String name, Scriptable start) Get a named property from the object.get
(Symbol key, Scriptable start) Return the value of the property with the specified key, or NOT_FOUND.Get the name of the set of objects implemented by this Java class.getDefaultValue
(Class<?> hint) Note that this method does not get forwarded to the delegee if thehint
parameter is null,ScriptRuntime.ScriptableClass
orScriptRuntime.FunctionClass
.Retrieve the delegee.Object[]
getIds()
Get an array of property ids.Get the parent scope of the object.Get the prototype of the object.boolean
has
(int index, Scriptable start) Indicates whether or not an indexed property is defined in an object.boolean
has
(String name, Scriptable start) Indicates whether or not a named property is defined in an object.boolean
has
(Symbol key, Scriptable start) Return true if the specified property exists.boolean
hasInstance
(Scriptable instance) The instanceof operator.protected Delegator
Crete new Delegator instance.void
put
(int index, Scriptable start, Object value) Sets an indexed property in this object.void
put
(String name, Scriptable start, Object value) Sets a named property in this object.void
put
(Symbol symbol, Scriptable start, Object value) Add a new property to to the object.void
setDelegee
(Scriptable obj) Set the delegee.void
setParentScope
(Scriptable parent) Set the parent scope of the object.void
setPrototype
(Scriptable prototype) Set the prototype of the object.
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Field Details
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obj
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Constructor Details
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Delegator
public Delegator()Create a Delegator prototype.This constructor should only be used for creating prototype objects of Delegator.
- See Also:
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Delegator
Create a new Delegator that forwards requests to a delegee Scriptable object.- Parameters:
obj
- the delegee- See Also:
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Method Details
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newInstance
Crete new Delegator instance. The default implementation calls this.getClass().newInstance().- See Also:
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getDelegee
Retrieve the delegee.- Returns:
- the delegee
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setDelegee
Set the delegee.- Parameters:
obj
- the delegee- See Also:
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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 interfaceScriptable
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get
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 interfaceScriptable
- Parameters:
name
- the name of the propertystart
- the object in which the lookup began- Returns:
- the value of the property (may be null), or NOT_FOUND
- See Also:
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get
Description copied from interface:SymbolScriptable
Return the value of the property with the specified key, or NOT_FOUND.- Specified by:
get
in interfaceSymbolScriptable
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get
Description copied from interface:Scriptable
Get a property from the object selected by an integral index.Identical to
get(String, Scriptable)
except that an integral index is used to select the property.- Specified by:
get
in interfaceScriptable
- Parameters:
index
- the numeric index for the propertystart
- the object in which the lookup began- Returns:
- the value of the property (may be null), or NOT_FOUND
- See Also:
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has
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 interfaceScriptable
- Parameters:
name
- the name of the propertystart
- the object in which the lookup began- Returns:
- true if and only if the named property is found in the object
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has
Description copied from interface:SymbolScriptable
Return true if the specified property exists.- Specified by:
has
in interfaceSymbolScriptable
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has
Description copied from interface:Scriptable
Indicates whether or not an indexed property is defined in an object.Does not traverse the prototype chain.
The property is specified by an integral index as defined for the
get
method.- Specified by:
has
in interfaceScriptable
- Parameters:
index
- the numeric index for the propertystart
- the object in which the lookup began- Returns:
- true if and only if the indexed property is found in the object
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put
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 causeset
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 beforeset
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 interfaceScriptable
- Parameters:
name
- the name of the propertystart
- the object whose property is being setvalue
- value to set the property to- See Also:
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put
Description copied from interface:SymbolScriptable
Add a new property to to the object.- Specified by:
put
in interfaceSymbolScriptable
- See Also:
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put
Description copied from interface:Scriptable
Sets an indexed property in this object.The property is specified by an integral index as defined for
get
.Identical to
put(String, Scriptable, Object)
except that an integral index is used to select the property.- Specified by:
put
in interfaceScriptable
- Parameters:
index
- the numeric index for the propertystart
- the object whose property is being setvalue
- value to set the property to- See Also:
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delete
Description copied from interface:Scriptable
Removes a property from this object. This operation corresponds to the ECMA [[Delete]] except that the no result is returned. The runtime will guarantee that this method is called only if the property exists. After this method is called, the runtime will call Scriptable.has to see if the property has been removed in order to determine the boolean result of the delete operator as defined by ECMA 11.4.1.A property can be made permanent by ignoring calls to remove it.
The property is specified by a String name as defined for
get
.To delete properties defined in a prototype chain, see deleteProperty in ScriptableObject.
- Specified by:
delete
in interfaceScriptable
- Parameters:
name
- the identifier for the property- See Also:
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delete
Description copied from interface:SymbolScriptable
Delete a property with the specified key.- Specified by:
delete
in interfaceSymbolScriptable
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delete
public void delete(int index) Description copied from interface:Scriptable
Removes a property from this object.The property is specified by an integral index as defined for
get
.To delete properties defined in a prototype chain, see deleteProperty in ScriptableObject.
Identical to
delete(String)
except that an integral index is used to select the property.- Specified by:
delete
in interfaceScriptable
- Parameters:
index
- the numeric index for the property- See Also:
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getPrototype
Description copied from interface:Scriptable
Get the prototype of the object.- Specified by:
getPrototype
in interfaceScriptable
- Returns:
- the prototype
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setPrototype
Description copied from interface:Scriptable
Set the prototype of the object.- Specified by:
setPrototype
in interfaceScriptable
- Parameters:
prototype
- the prototype to set- See Also:
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getParentScope
Description copied from interface:Scriptable
Get the parent scope of the object.- Specified by:
getParentScope
in interfaceScriptable
- Returns:
- the parent scope
- See Also:
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setParentScope
Description copied from interface:Scriptable
Set the parent scope of the object.- Specified by:
setParentScope
in interfaceScriptable
- Parameters:
parent
- the parent scope to set- See Also:
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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 interfaceScriptable
- Returns:
- an array of Objects. Each entry in the array is either a java.lang.String or a java.lang.Number
- See Also:
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getDefaultValue
Note that this method does not get forwarded to the delegee if thehint
parameter is null,ScriptRuntime.ScriptableClass
orScriptRuntime.FunctionClass
. Instead the object itself is returned.- Specified by:
getDefaultValue
in interfaceScriptable
- Parameters:
hint
- the type hint- Returns:
- the default value
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hasInstance
Description copied from interface:Scriptable
The instanceof operator.The JavaScript code "lhs instanceof rhs" causes rhs.hasInstance(lhs) to be called.
The return value is implementation dependent so that embedded host objects can return an appropriate value. See the JS 1.3 language documentation for more detail.
This operator corresponds to the proposed EMCA [[HasInstance]] operator.
- Specified by:
hasInstance
in interfaceScriptable
- Parameters:
instance
- The value that appeared on the LHS of the instanceof operator- Returns:
- an implementation dependent value
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call
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 interfaceCallable
- Specified by:
call
in interfaceFunction
- Parameters:
cx
- the current Context for this threadscope
- 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 JavaScriptthis
objectargs
- the array of arguments- Returns:
- the result of the call
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construct
Note that if thedelegee
isnull
, this method creates a new instance of the Delegator itself rather than forwarding the call to thedelegee
. This permits the use of Delegator prototypes.- Specified by:
construct
in interfaceConstructable
- Specified by:
construct
in interfaceFunction
- Parameters:
cx
- the current Context for this threadscope
- an enclosing scope of the caller except when the function is called from a closure.args
- the array of arguments- Returns:
- the allocated object
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