org.ringojs.engine

Class ReloadableScript

java.lang.Object

org.ringojs.engine.ReloadableScript

public class ReloadableScript
extends Object

This class represents a JavaScript Resource.

Author:

Hannes Wallnoefer, hannes@helma.at

Constructor Summary

Constructors

Constructor and Description
ReloadableScript(Resource source, RhinoEngine engine) Construct a Script from the given script resource.

Method Summary

Modifier and Type	Method and Description
protected void	addDependency(ReloadableScript script) Register a script that this script depends on.
protected Object	compileScript(org.mozilla.javascript.Context cx) Get a script from a single script file.
boolean	equals(Object obj) Equal check delegates to source.
Object	evaluate(org.mozilla.javascript.Scriptable scope, org.mozilla.javascript.Context cx, RingoWorker worker) Evaluate the script on a module scope and return the result
protected long	getChecksum() Get the checksum of the script.
protected long	getNestedChecksum(Set<ReloadableScript> set) Get the recursive checksum of this script as a dependency.
Object	getScript(org.mozilla.javascript.Context cx, RingoWorker worker) Get the actual compiled script.
Resource	getSource() Get the script's source resource.
int	hashCode() Hash code delegates to source.
protected org.mozilla.javascript.Scriptable	load(org.mozilla.javascript.Scriptable prototype, org.mozilla.javascript.Context cx, org.mozilla.javascript.Scriptable module, RingoWorker worker) Get a module scope loaded with this script

Methods inherited from class java.lang.Object

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

Constructor Detail

ReloadableScript

public ReloadableScript(Resource source,
                        RhinoEngine engine)

Construct a Script from the given script resource.

Parameters:

source - the JavaScript resource or repository containing the script.

engine - the rhino engine

Method Detail

getSource

public Resource getSource()

Get the script's source resource.

Returns:

the script's source resource.

getScript

public Object getScript(org.mozilla.javascript.Context cx,
                        RingoWorker worker)
                 throws org.mozilla.javascript.JavaScriptException,
                        IOException

Get the actual compiled script.

Parameters:

cx - the current Context

Returns:

the compiled and up-to-date script

Throws:

org.mozilla.javascript.JavaScriptException - if an error occurred compiling the script code

IOException - if an error occurred reading the script file

compileScript

protected Object compileScript(org.mozilla.javascript.Context cx)
                        throws org.mozilla.javascript.JavaScriptException,
                               IOException

Get a script from a single script file.

Parameters:

cx - the current Context

Returns:

the compiled and up-to-date script

Throws:

org.mozilla.javascript.JavaScriptException - if an error occurred compiling the script code

IOException - if an error occurred reading the script file

evaluate

public Object evaluate(org.mozilla.javascript.Scriptable scope,
                       org.mozilla.javascript.Context cx,
                       RingoWorker worker)
                throws org.mozilla.javascript.JavaScriptException,
                       IOException

Evaluate the script on a module scope and return the result

Parameters:

scope - the scope to evaluate the script on

cx - the rhino context

Returns:

the result of the evaluation

Throws:

org.mozilla.javascript.JavaScriptException - if an error occurred evaluating the script file

IOException - if an error occurred reading the script file

load

protected org.mozilla.javascript.Scriptable load(org.mozilla.javascript.Scriptable prototype,
                                                 org.mozilla.javascript.Context cx,
                                                 org.mozilla.javascript.Scriptable module,
                                                 RingoWorker worker)
                                          throws org.mozilla.javascript.JavaScriptException,
                                                 IOException

Get a module scope loaded with this script

Parameters:

prototype - the prototype for the module, usually the shared top level scope

cx - the rhino context

module - the preexisting module for this resource if available

worker - the worker instance loading this module

Returns:

a new module scope

Throws:

org.mozilla.javascript.JavaScriptException - if an error occurred evaluating the script file

IOException - if an error occurred reading the script file

getChecksum

protected long getChecksum()
                    throws IOException

Get the checksum of the script. This includes the transitive sum of loaded module checksums, as modules need to be re-evaluated even if just a dependency has been updated.

Returns:

the evaluation checksum for this script

Throws:

IOException - source could not be checked because of an I/O error

getNestedChecksum

protected long getNestedChecksum(Set<ReloadableScript> set)
                          throws IOException

Get the recursive checksum of this script as a dependency. Since the checksum field may not be up-to-date we directly get the checksum from the underlying resource.

Parameters:

set - visited script set to prevent cyclic invokation

Returns:

the nested checksum

Throws:

IOException - source could not be checked because of an I/O error

addDependency

protected void addDependency(ReloadableScript script)

Register a script that this script depends on. This means that the script has been loaded directly or indirectly from the top scope of this module. The purpose of this is to keep track of modules loaded indirectly by shared modules, as we wouldn't normally notice they have been updated. Scripts loaded __after__ a module has been loaded do not count as dependencies, as they will be checked again at runtime.

Parameters:

script - a script we depend on

hashCode

public int hashCode()

Hash code delegates to source.

Overrides:

hashCode in class Object

Returns:

the hash code

equals

public boolean equals(Object obj)

Equal check delegates to source.

Overrides:

equals in class Object

Parameters:

obj - the object to compare ourself to

Returns:

true if it is a script with the same resource