org.grouplens.lenskit.eval.script

Class EvalScriptEngine

java.lang.Object

org.grouplens.lenskit.eval.script.EvalScriptEngine

public class EvalScriptEngine
extends Object

Load and process configuration files. Also provides helper methods used by the configuration scripts to locate & invoke methods.

Since:

0.10

Field Summary

Fields

Modifier and Type	Field and Description
protected ClassLoader	classLoader
protected ClassDirectory	directory
protected Properties	properties
protected groovy.lang.GroovyShell	shell

Constructor Summary

Constructors

Constructor and Description
EvalScriptEngine() Construct a new script engine.
EvalScriptEngine(ClassLoader loader) Construct a new script engine.
EvalScriptEngine(ClassLoader loader, Properties props) Construct a new script engine.

Method Summary

Modifier and Type	Method and Description
EvalProject	createProject() Create a new eval project.
<T> Class<? extends org.apache.commons.lang3.builder.Builder>	getBuilderForType(Class<T> type) Get a command for a type.
protected void	loadExternalMethods() Register a default set of external methods.
EvalProject	loadProject(File file) Load a set of evaluations from a script file.
Object	loadProject(Reader in) Load a set of evaluations from an input stream.
Class<? extends org.apache.commons.lang3.builder.Builder>	lookupBuilder(String name) Find a builder with a particular name if it exists.
Class<?>	lookupMethod(String name) Look up a registered method of any type.
Class<? extends EvalTask>	lookupTask(String name) Find a task with a particular name if it exists.
<T> void	registerCommand(Class<T> type, Class<? extends org.apache.commons.lang3.builder.Builder> command) Register a builder class for a type.
Object	runScript(EvalScript script, EvalProject project) Run an evaluation config script and get the evaluations it produces.
Object	runScript(File file, EvalProject project) Run a script from a file.
Object	runScript(Reader in, EvalProject project) Run a script from a reader.

Methods inherited from class java.lang.Object

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

Field Detail

classLoader

protected ClassLoader classLoader

directory

protected ClassDirectory directory

shell

protected groovy.lang.GroovyShell shell

properties

@Nullable
protected final Properties properties

Constructor Detail

EvalScriptEngine

public EvalScriptEngine()

Construct a new script engine. The engine uses the current thread's classloader.

EvalScriptEngine

public EvalScriptEngine(ClassLoader loader)

Construct a new script engine.

Parameters:

loader - The class loader to use.

EvalScriptEngine

public EvalScriptEngine(ClassLoader loader,
                        @Nullable
                        Properties props)

Construct a new script engine.

Parameters:

loader - The class loader to use.

props - Additional properties to use when creating new projects.

See Also:

EvalProject.EvalProject(java.util.Properties)

Method Detail

createProject

public EvalProject createProject()

Create a new eval project.

Returns:

The eval project.

runScript

public Object runScript(File file,
                        EvalProject project)
                 throws IOException,
                        TaskExecutionException

Run a script from a file.

Parameters:

file - The file to run.

project - The project to run the script against.

Returns:

The script as parsed and compiled by Groovy.

Throws:

IOException - if the file cannot be read.

TaskExecutionException

runScript

public Object runScript(Reader in,
                        EvalProject project)
                 throws IOException

Run a script from a reader.

Parameters:

in - The reader to read.

project - The project to run the script against.

Returns:

The script as parsed and compiled by Groovy.

Throws:

IOException

runScript

@Nullable
public Object runScript(EvalScript script,
                                  EvalProject project)
                           throws TaskExecutionException

Run an evaluation config script and get the evaluations it produces.

Parameters:

script - The script to run (as loaded by Groovy)

project - The project to run the script on.

Returns:

The return value of the script.

Throws:

TaskExecutionException - if the script is invalid or produces an error.

loadProject

public EvalProject loadProject(File file)
                        throws TaskExecutionException,
                               IOException

Load a set of evaluations from a script file.

Parameters:

file - A Groovy script to configure the evaluator.

Returns:

A list of evaluations to run.

Throws:

TaskExecutionException - if there is a configuration error

IOException - if there is an error reading the file

loadProject

public Object loadProject(Reader in)
                   throws TaskExecutionException,
                          IOException

Load a set of evaluations from an input stream.

Parameters:

in - The input stream

Returns:

A list of evaluations

Throws:

TaskExecutionException - if there is a configuration error

IOException

lookupMethod

public Class<?> lookupMethod(@Nonnull
                             String name)

Look up a registered method of any type. The currently supported types are builders and tasks.

Parameters:

name - The method name.

Returns:

The method implementation class, or null if it the method is not found.

lookupTask

@CheckForNull
 @Nullable
public Class<? extends EvalTask> lookupTask(@Nonnull
                                                                     String name)

Find a task with a particular name if it exists.

Parameters:

name - The name of the command

Returns:

The command factory or null if no such factory exists.

lookupBuilder

@CheckForNull
 @Nullable
public Class<? extends org.apache.commons.lang3.builder.Builder> lookupBuilder(@Nonnull
                                                                                                        String name)

Find a builder with a particular name if it exists.

Parameters:

name - The name of the command

Returns:

The command factory or null if no such factory exists.

getBuilderForType

public <T> Class<? extends org.apache.commons.lang3.builder.Builder> getBuilderForType(Class<T> type)

Get a command for a type. It consults registered commands and looks for the BuiltBy annotation.

Parameters:

type - A type that needs to be built.

Returns:

A command class to build type, or null if none can be found.

See Also:

registerCommand(java.lang.Class<T>, java.lang.Class<? extends org.apache.commons.lang3.builder.Builder>)

registerCommand

public <T> void registerCommand(Class<T> type,
                                Class<? extends org.apache.commons.lang3.builder.Builder> command)

Register a builder class for a type. Used to allow commands to be found for types where the type cannot be augmented with the BuiltBy annotation.

Type Parameters:

T - The type to build (type parameter).

Parameters:

type - The type to build.

command - A class that can build instances of type.

loadExternalMethods

protected void loadExternalMethods()

Register a default set of external methods.