sleep.runtime

Class ScriptLoader


public class ScriptLoader
extends Object

The ScriptLoader is a convienence container for instantiating and managing ScriptInstances.

To load a script from a file and run it:

 ScriptLoader   loader = new ScriptLoader();
 ScriptInstance script = loader.loadScript("script.sl");

 script.runScript();
 

The above will load the file script.sl and then execute it immediately.

Installation of loadable bridges you create can also be managed by the ScriptLoader.

A loadable bridge is installed into the language by adding it to a script loader class. There are two types of bridges. The two types are specific and global bridges.

The load and unload methods for a specific bridge are executed for every script load and unload, no matter what.

A global bridge is installed once for each script environment. If scripts are sharing an environment there is no sense in loading stuff into the environment more than once. This is why global bridges exist.

An example of adding a loadable bridge to a script loader:

 ScriptLoader loader = new ScriptLoader()
 loader.addSpecificBridge(new MyLoadableBridge());
 

There is a difference between "loading" and "compiling" a script:

This class contains several methods to either load or compile a script. Loading a script instantiates a script environment, registers the script with the script loader, and registers all of the appropriate bridges with the script on top of compiling the script.

To compile a script means to produce a runnable Block of code. On its own a Block is not really runnable as a script environment is needed. For functions like eval(), include(), etc.. it makes sense to compile a script as one may want to run the block of code within the environment of the calling script. Using the compile method saves on the overhead of unnecessary script environment creation and bridge registration.

Hopefully this helped to clarify things. :)

See Also:
Loadable, ScriptInstance

Field Summary

protected static HashMap
BLOCK_CACHE
cache for parsed scripts mantained (optionally) by the script loader.
protected LinkedList
bridgesg
global bridges
protected LinkedList
bridgess
specific bridges
protected boolean
disableConversions
protected LinkedList
loadedScripts
loaded scripts
protected LinkedList
paths
path to search for jar files imported using [import * from: *] syntax
protected HashMap
scripts
loaded scripts except referable by key

Constructor Summary

ScriptLoader()
initializes the script loader

Method Summary

void
addGlobalBridge(Loadable l)
A global bridge is loaded into an environment once and only once.
void
addSpecificBridge(Loadable l)
A specific bridge is loaded into *every* script regardless of wether or not the environment is shared.
Block
compileScript(File file)
compiles the specified script file
Block
compileScript(String fileName)
compiles the specified script file
Block
compileScript(String name, InputStream stream)
compiles a script using the specified stream as a source
Block
compileScript(String name, String code)
compiles the specified script into a runnable block
String
getCharset()
ScriptEnvironment
getFirstScriptEnvironment()
Convienence method to return the script environment of the first script tht was loaded, returns null if no scripts are loaded
LinkedList
getScripts()
Returns a linked list of all loaded ScriptInstance objects
HashMap
getScriptsByKey()
Returns a HashMap with all loaded scripts, the key is a string which is just the filename, the value is a ScriptInstance object
Set
getScriptsToLoad(Set configured)
A convienence method to determine the set of scripts to "load" based on a passed in set of scripts that are currently configured.
Set
getScriptsToUnload(Set configured)
A convienence method to determine the set of scripts to "unload" based on a passed in set of scripts that are currently configured.
protected void
initDefaultBridges()
method call to initialize the default bridges, if you want to change the default bridges subclass this class and override this method
boolean
isCharsetConversions()
boolean
isLoaded(String name)
Determines wether or not the script is loaded by checking if the specified key exists in the script db.
ScriptInstance
loadScript(File file)
Loads the specified script file
ScriptInstance
loadScript(File file, Hashtable env)
Loads the specified script file, uses the specified hashtable for the environment
ScriptInstance
loadScript(String fileName)
Loads the specified script file
ScriptInstance
loadScript(String fileName, Hashtable env)
Loads the specified script file, uses the specified hashtable for the environment
ScriptInstance
loadScript(String name, InputStream stream)
loads a script from the specified inputstream
ScriptInstance
loadScript(String name, InputStream stream, Hashtable env)
loads a script from the specified input stream using the specified hashtable as a shared environment
ScriptInstance
loadScript(String name, String code, Hashtable env)
loads the specified script
ScriptInstance
loadScript(String name, Block code, Hashtable env)
ScriptInstance
loadSerialized(File script, Hashtable env)
Load a serialized version of the script iff a serialized version exists, and its modification time is greater than the modification time of the script.
ScriptInstance
loadSerialized(String name, InputStream stream, Hashtable env)
Loads a serialized script from the specified input stream with the specified name
static void
saveSerialized(ScriptInstance si)
Saves a serialized version of the compiled script to scriptname.bin.
static void
saveSerialized(ScriptInstance si, OutputStream stream)
Saves a serialized version of the ScriptInstance si to the specified output stream
void
setCharset(String charset)
If charset conversion is enabled and charset is set, then the stream will be read using specified charset.
void
setCharsetConversion(boolean b)
Java by default maps characters from an 8bit ascii file to an internal 32bit unicode representation.
HashMap
setGlobalCache(boolean setting)
The Sleep script loader can optionally cache parsed script files once they are loaded.
void
unloadScript(String filename)
unload a script
void
unloadScript(ScriptInstance script)
unload a script

Field Details

BLOCK_CACHE

protected static HashMap BLOCK_CACHE
cache for parsed scripts mantained (optionally) by the script loader.

bridgesg

protected LinkedList bridgesg
global bridges

bridgess

protected LinkedList bridgess
specific bridges

disableConversions

protected boolean disableConversions

loadedScripts

protected LinkedList loadedScripts
loaded scripts

paths

protected LinkedList paths
path to search for jar files imported using [import * from: *] syntax

scripts

protected HashMap scripts
loaded scripts except referable by key

Constructor Details

ScriptLoader

public ScriptLoader()
initializes the script loader

Method Details

addGlobalBridge

public void addGlobalBridge(Loadable l)
A global bridge is loaded into an environment once and only once. This way if the environment is shared among multiple script instances this will save on both memory and script load time

addSpecificBridge

public void addSpecificBridge(Loadable l)
A specific bridge is loaded into *every* script regardless of wether or not the environment is shared. Useful for modifying the script instance while it is being in processed. Specific bridges are the first thing that happens after the script code is parsed

compileScript

public Block compileScript(File file)
            throws IOException,
                   YourCodeSucksException
compiles the specified script file

compileScript

public Block compileScript(String fileName)
            throws IOException,
                   YourCodeSucksException
compiles the specified script file

compileScript

public Block compileScript(String name,
                           InputStream stream)
            throws YourCodeSucksException,
                   IOException
compiles a script using the specified stream as a source

compileScript

public Block compileScript(String name,
                           String code)
            throws YourCodeSucksException
compiles the specified script into a runnable block

getCharset

public String getCharset()

getFirstScriptEnvironment

public ScriptEnvironment getFirstScriptEnvironment()
Convienence method to return the script environment of the first script tht was loaded, returns null if no scripts are loaded

getScripts

public LinkedList getScripts()
Returns a linked list of all loaded ScriptInstance objects

getScriptsByKey

public HashMap getScriptsByKey()
Returns a HashMap with all loaded scripts, the key is a string which is just the filename, the value is a ScriptInstance object

getScriptsToLoad

public Set getScriptsToLoad(Set configured)
A convienence method to determine the set of scripts to "load" based on a passed in set of scripts that are currently configured. The configured scripts are compared to the loaded scripts. Scripts that are configured but not loaded are determined to be in need of loading. The return Set contains String objects of the script names. The passed in Set is expected to be the same thing (a bunch of Strings).

getScriptsToUnload

public Set getScriptsToUnload(Set configured)
A convienence method to determine the set of scripts to "unload" based on a passed in set of scripts that are currently configured. The configured scripts are compared to the loaded scripts. Scripts that are loaded but not configured are determined to be in need of unloading. The return Set contains String objects of the script names. The passed in Set is expected to be the same thing (a bunch of Strings).

initDefaultBridges

protected void initDefaultBridges()
method call to initialize the default bridges, if you want to change the default bridges subclass this class and override this method

isCharsetConversions

public boolean isCharsetConversions()

isLoaded

public boolean isLoaded(String name)
Determines wether or not the script is loaded by checking if the specified key exists in the script db.

loadScript

public ScriptInstance loadScript(File file)
            throws IOException,
                   YourCodeSucksException
Loads the specified script file

loadScript

public ScriptInstance loadScript(File file,
                                 Hashtable env)
            throws IOException,
                   YourCodeSucksException
Loads the specified script file, uses the specified hashtable for the environment

loadScript

public ScriptInstance loadScript(String fileName)
            throws IOException,
                   YourCodeSucksException
Loads the specified script file

loadScript

public ScriptInstance loadScript(String fileName,
                                 Hashtable env)
            throws IOException,
                   YourCodeSucksException
Loads the specified script file, uses the specified hashtable for the environment

loadScript

public ScriptInstance loadScript(String name,
                                 InputStream stream)
            throws YourCodeSucksException,
                   IOException
loads a script from the specified inputstream

loadScript

public ScriptInstance loadScript(String name,
                                 InputStream stream,
                                 Hashtable env)
            throws YourCodeSucksException,
                   IOException
loads a script from the specified input stream using the specified hashtable as a shared environment

loadScript

public ScriptInstance loadScript(String name,
                                 String code,
                                 Hashtable env)
            throws YourCodeSucksException
loads the specified script

loadScript

public ScriptInstance loadScript(String name,
                                 Block code,
                                 Hashtable env)

loadSerialized

public ScriptInstance loadSerialized(File script,
                                     Hashtable env)
            throws IOException,
                   ClassNotFoundException
Load a serialized version of the script iff a serialized version exists, and its modification time is greater than the modification time of the script. Also handles the muss and fuss of reserializing the script if it has to reload the script. Personally I didn't find much of a startup time decrease when loading the scripts serialized versus parsing them each time. Theres a command 'bload' in the console to benchmark loading a script normally versus serialized. Try it.
Parameters:
script - a file object pointing to the script file...

loadSerialized

public ScriptInstance loadSerialized(String name,
                                     InputStream stream,
                                     Hashtable env)
            throws IOException,
                   ClassNotFoundException
Loads a serialized script from the specified input stream with the specified name

saveSerialized

public static void saveSerialized(ScriptInstance si)
            throws IOException
Saves a serialized version of the compiled script to scriptname.bin.

saveSerialized

public static void saveSerialized(ScriptInstance si,
                                  OutputStream stream)
            throws IOException
Saves a serialized version of the ScriptInstance si to the specified output stream

setCharset

public void setCharset(String charset)
If charset conversion is enabled and charset is set, then the stream will be read using specified charset.

setCharsetConversion

public void setCharsetConversion(boolean b)
Java by default maps characters from an 8bit ascii file to an internal 32bit unicode representation. How this mapping is done is called a character set encoding. Sometimes this conversion can frustrate scripters making them say "hey, I didn't put that character in my script". You can use this option to ensure sleep disables charset conversions for scripts loaded with this script loader

setGlobalCache

public HashMap setGlobalCache(boolean setting)
The Sleep script loader can optionally cache parsed script files once they are loaded. This is useful if you will have several script loader instances loading the same script files in isolated objects.

unloadScript

public void unloadScript(String filename)
unload a script

unloadScript

public void unloadScript(ScriptInstance script)
unload a script