org.mozilla.javascript

Class NativeWith

Implemented Interfaces:
IdFunctionCall, Scriptable, Serializable

public class NativeWith
extends java.lang.Object
implements Scriptable, IdFunctionCall, Serializable

This class implements the object lookup required for the with statement. It simply delegates every action to its prototype except for operations on its parent.

Field Summary

protected Scriptable
parent
protected Scriptable
prototype

Fields inherited from interface org.mozilla.javascript.Scriptable

NOT_FOUND

Constructor Summary

NativeWith(Scriptable parent, Scriptable prototype)

Method Summary

void
delete(String id)
Removes a property from this object.
void
delete(int index)
Removes a property from this object.
Object
execIdCall(IdFunctionObject f, Context cx, Scriptable scope, Scriptable thisObj, Object[] args)
'thisObj' will be null if invoked as constructor, in which case instance of Scriptable should be returned
Object
get(String id, Scriptable start)
Get a named property from the object.
Object
get(int index, Scriptable start)
Get a property from the object selected by an integral index.
String
getClassName()
Get the name of the set of objects implemented by this Java class.
Object
getDefaultValue(Class typeHint)
Get the default value of the object with a given hint.
Object[]
getIds()
Get an array of property ids.
Scriptable
getParentScope()
Get the parent scope of the object.
Scriptable
getPrototype()
Get the prototype of the object.
boolean
has(String id, Scriptable start)
Indicates whether or not a named property is defined in an object.
boolean
has(int index, Scriptable start)
Indicates whether or not an indexed property is defined in an object.
boolean
hasInstance(Scriptable value)
The instanceof operator.
void
put(String id, Scriptable start, Object value)
Sets a named property in this object.
void
put(int index, Scriptable start, Object value)
Sets an indexed property in this object.
void
setParentScope(Scriptable parent)
Set the parent scope of the object.
void
setPrototype(Scriptable prototype)
Set the prototype of the object.
protected Object
updateDotQuery(boolean value)
Must return null to continue looping or the final collection result.

Field Details

parent

protected Scriptable parent

prototype

protected Scriptable prototype

Constructor Details

NativeWith

protected NativeWith(Scriptable parent,
                     Scriptable prototype)

Method Details

delete

public void delete(String id)
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 interface Scriptable
Parameters:
See Also:
org.mozilla.javascript.Scriptable.get, org.mozilla.javascript.ScriptableObject.deleteProperty

delete

public void delete(int index)
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 interface Scriptable
Parameters:
index - the numeric index for the property
See Also:
org.mozilla.javascript.Scriptable.get, org.mozilla.javascript.ScriptableObject.deleteProperty

execIdCall

public Object execIdCall(IdFunctionObject f,
                         Context cx,
                         Scriptable scope,
                         Scriptable thisObj,
                         Object[] args)
'thisObj' will be null if invoked as constructor, in which case instance of Scriptable should be returned
Specified by:
execIdCall in interface IdFunctionCall

get

public Object get(String id,
                  Scriptable start)
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 codeJava 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
Parameters:
start - the object in which the lookup began
Returns:
the value of the property (may be null), or NOT_FOUND

get

public Object get(int index,
                  Scriptable start)
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 interface Scriptable
Parameters:
index - the numeric index for the property
start - the object in which the lookup began
Returns:
the value of the property (may be null), or NOT_FOUND

getClassName

public String getClassName()
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

getDefaultValue

public Object getDefaultValue(Class typeHint)
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
Parameters:
Returns:
the default value

getIds

public Object[] getIds()
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
Returns:
an array of Objects. Each entry in the array is either a java.lang.String or a java.lang.Number

getParentScope

public Scriptable getParentScope()
Get the parent scope of the object.
Specified by:
getParentScope in interface Scriptable
Returns:
the parent scope

getPrototype

public Scriptable getPrototype()
Get the prototype of the object.
Specified by:
getPrototype in interface Scriptable
Returns:
the prototype

has

public boolean has(String id,
                   Scriptable start)
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
Parameters:
start - the object in which the lookup began
Returns:
true if and only if the named property is found in the object
See Also:
org.mozilla.javascript.Scriptable.get, org.mozilla.javascript.ScriptableObject.getProperty

has

public boolean has(int index,
                   Scriptable start)
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 interface Scriptable
Parameters:
index - the numeric index for the property
start - the object in which the lookup began
Returns:
true if and only if the indexed property is found in the object
See Also:
org.mozilla.javascript.Scriptable.get, org.mozilla.javascript.ScriptableObject.getProperty

hasInstance

public boolean hasInstance(Scriptable value)
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 interface Scriptable
Parameters:
Returns:
an implementation dependent value

put

public void put(String id,
                Scriptable start,
                Object value)
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
Parameters:
start - the object whose property is being set
value - value to set the property to
See Also:
org.mozilla.javascript.Scriptable.has, org.mozilla.javascript.Scriptable.get, org.mozilla.javascript.ScriptableObject.putProperty, org.mozilla.javascript.Context.toObject

put

public void put(int index,
                Scriptable start,
                Object value)
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 interface Scriptable
Parameters:
index - the numeric index for the property
start - the object whose property is being set
value - value to set the property to
See Also:
org.mozilla.javascript.Scriptable.has, org.mozilla.javascript.Scriptable.get, Scriptable.put(String,Scriptable,Object), org.mozilla.javascript.ScriptableObject.putProperty

setParentScope

public void setParentScope(Scriptable parent)
Set the parent scope of the object.
Specified by:
setParentScope in interface Scriptable
Parameters:
parent - the parent scope to set

setPrototype

public void setPrototype(Scriptable prototype)
Set the prototype of the object.
Specified by:
setPrototype in interface Scriptable
Parameters:
prototype - the prototype to set

updateDotQuery

protected Object updateDotQuery(boolean value)
Must return null to continue looping or the final collection result.