org.mozilla.javascript.commonjs.module
Class Require

java.lang.Object
  org.mozilla.javascript.ScriptableObject
      org.mozilla.javascript.IdScriptableObject
          org.mozilla.javascript.BaseFunction
              org.mozilla.javascript.commonjs.module.Require

All Implemented Interfaces:

java.io.Serializable, Callable, ConstProperties, DebuggableObject, Function, IdFunctionCall, Scriptable

public class Require
extends BaseFunction

Implements the require() function as defined by Common JS modules.

Thread safety

You will ordinarily create one instance of require() for every top-level scope. This ordinarily means one instance per program execution, except if you use shared top-level scopes and installing most objects into them. Module loading is thread safe, so using a single require() in a shared top-level scope is also safe.

Creation

If you need to create many otherwise identical require() functions for different scopes, you might want to use RequireBuilder for convenience.

Making it available

In order to make the require() function available to your JavaScript program, you need to invoke either install(Scriptable) or requireMain(Context, String).

Version:

$Id: Require.java,v 1.4 2011/04/07 20:26:11 hannes%helma.at Exp $

Author:

Attila Szegedi

See Also:

Serialized Form

Field Summary

Fields inherited from class org.mozilla.javascript.ScriptableObject

CONST, DONTENUM, EMPTY, PERMANENT, READONLY, UNINITIALIZED_CONST

Fields inherited from interface org.mozilla.javascript.Scriptable

NOT_FOUND

Constructor Summary

Require(Context cx, Scriptable nativeScope, ModuleScriptProvider moduleScriptProvider, Script preExec, Script postExec, boolean sandboxed)
Creates a new instance of the require() function.

Method Summary

java.lang.Object	call(Context cx, Scriptable scope, Scriptable thisObj, java.lang.Object[] args) Should be overridden.
Scriptable	construct(Context cx, Scriptable scope, java.lang.Object[] args) Call the function as a constructor.
int	getArity()
java.lang.String	getFunctionName()
int	getLength()
void	install(Scriptable scope) Binds this instance of require() into the specified scope under the property name "require".
Scriptable	requireMain(Context cx, java.lang.String mainModuleId) Calling this method establishes a module as being the main module of the program to which this require() instance belongs.

Methods inherited from class org.mozilla.javascript.BaseFunction

createObject, execIdCall, fillConstructorProperties, findInstanceIdInfo, findPrototypeId, getClassName, getClassPrototype, getInstanceIdName, getInstanceIdValue, getMaxInstanceId, getPrototypeProperty, getTypeOf, hasInstance, hasPrototypeProperty, initPrototypeId, setImmunePrototypeProperty, setInstanceIdValue

Methods inherited from class org.mozilla.javascript.IdScriptableObject

activatePrototypeMap, addIdFunctionProperty, defaultGet, defaultPut, defineOwnProperty, delete, exportAsJSClass, get, getAttributes, getOwnPropertyDescriptor, has, hasPrototypeMap, incompatibleCallError, initPrototypeConstructor, initPrototypeMethod, initPrototypeValue, instanceIdInfo, put, setAttributes, setInstanceIdAttributes

Methods inherited from class org.mozilla.javascript.ScriptableObject

applyDescriptorToAttributeBitset, associateValue, avoidObjectDetection, buildDataDescriptor, callMethod, callMethod, checkPropertyChange, checkPropertyDefinition, defineClass, defineClass, defineClass, defineConst, defineConstProperty, defineFunctionProperties, defineOwnProperties, defineOwnProperty, defineProperty, defineProperty, defineProperty, defineProperty, delete, deleteProperty, deleteProperty, ensureScriptable, ensureScriptableObject, equivalentValues, get, get, getAllIds, getArrayPrototype, getAssociatedValue, getAttributes, getAttributes, getAttributes, getClassPrototype, getDefaultValue, getDefaultValue, getFunctionPrototype, getGetterOrSetter, getIds, getObjectPrototype, getParentScope, getProperty, getProperty, getPropertyIds, getPrototype, getSlot, getTopLevelScope, getTopScopeValue, getTypedProperty, getTypedProperty, has, hasProperty, hasProperty, isAccessorDescriptor, isConst, isDataDescriptor, isEmpty, isExtensible, isFalse, isGenericDescriptor, isGetterOrSetter, isSealed, isTrue, preventExtensions, put, putConst, putConstProperty, putProperty, putProperty, redefineProperty, sameValue, sealObject, setAttributes, setAttributes, setAttributes, setGetterOrSetter, setParentScope, setPrototype, size

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.mozilla.javascript.Scriptable

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

Constructor Detail

Require

public Require(Context cx,
               Scriptable nativeScope,
               ModuleScriptProvider moduleScriptProvider,
               Script preExec,
               Script postExec,
               boolean sandboxed)

Creates a new instance of the require() function. Upon constructing it, you will either want to install it in the global (or some other) scope using install(Scriptable), or alternatively, you can load the program's main module using requireMain(Context, String) and then act on the main module's exports.

Parameters:

cx - the current context

nativeScope - a scope that provides the standard native JavaScript objects.

moduleScriptProvider - a provider for module scripts

preExec - an optional script that is executed in every module's scope before its module script is run.

postExec - an optional script that is executed in every module's scope after its module script is run.

sandboxed - if set to true, the require function will be sandboxed. This means that it doesn't have the "paths" property, and also that the modules it loads don't export the "module.uri" property.

Method Detail

requireMain

public Scriptable requireMain(Context cx,
                              java.lang.String mainModuleId)

Calling this method establishes a module as being the main module of the program to which this require() instance belongs. The module will be loaded as if require()'d and its "module" property will be set as the "main" property of this require() instance. You have to call this method before the module has been loaded (that is, the call to this method must be the first to require the module and thus trigger its loading). Note that the main module will execute in its own scope and not in the global scope. Since all other modules see the global scope, executing the main module in the global scope would open it for tampering by other modules.

Parameters:

cx - the current context

mainModuleId - the ID of the main module

Returns:

the "exports" property of the main module

Throws:

java.lang.IllegalStateException - if the main module is already loaded when required, or if this require() instance already has a different main module set.

install

public void install(Scriptable scope)

Binds this instance of require() into the specified scope under the property name "require".

Parameters:

scope - the scope where the require() function is to be installed.

call

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

Description copied from class: BaseFunction

Should be overridden.

Specified by:

call in interface Callable

Specified by:

call in interface Function

Overrides:

call in class BaseFunction

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

Overrides:

construct in class BaseFunction

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

getFunctionName

public java.lang.String getFunctionName()

Overrides:

getFunctionName in class BaseFunction

getArity

public int getArity()

Overrides:

getArity in class BaseFunction

getLength

public int getLength()

Overrides:

getLength in class BaseFunction