org.omegahat.Environment.Interpreter
Class BasicEvaluator

java.lang.Object
  |
  +--org.omegahat.Environment.Interpreter.BasicEvaluator

All Implemented Interfaces:

DatabaseCustomer, Evaluator, ManagedEvaluatorInt, java.lang.Runnable, java.io.Serializable

Direct Known Subclasses:

UtilityEvaluator

public class BasicEvaluator

extends java.lang.Object

implements DatabaseCustomer, java.io.Serializable, ManagedEvaluatorInt, java.lang.Runnable

The standard low-level evaluator used in the interactive Omegahat language from which most of the others are derived. This controls things such as

• parsing and evaluating top-level tasks;
• displaying results of tasks;
• maintaining a history of the tasks;
• managing the stack of input sources;
• database management and variable lookups;
• Resolving class names and managing new elements to the classpath and dynamically compiled classes;
• notification of evaluation events such as starting and ending a top-level task, sub-expression evaluation so that debuggers can control the evaluator, errors, etc.

Other evaluators provide additional facilities and methods to make them more useful.

See Also:

GUIHelpEvaluator, InteractiveEvaluator, SignallableEvaluator, TaskQueueEvaluator, UserClassEvaluator, TracingEvaluator, UtilityEvaluator, OrbacusEvaluator, Serialized Form

Field Summary

protected boolean	allowUnrestrictedAccess
protected ClassLocatorInt	class_lists
protected ExpressionInt	currentExpression Stores the sub-expression within the expression tree that is currently being evaluated.
protected java.lang.Object	data User-specifiable data that can be retrieved by the different expressions as they are evaluated without having to supply the information as an argument.
protected SearchPath	databases Ordered container of databases in which omegahat variables are stored and the evaluation of expressions looks for referenced variables.
protected Debugger	debugger The object to use for debugging errors as they arise in the evaluation of expressions by this evaluator.
protected int	DefaultAttachIndex The default position into which databases are added to the search path.
protected Database	defaultDatabase
protected DynamicClassLoader	dynamicClassLoader
protected ErrorHandler	errorHandler
protected EvaluationEvent	evaluationEvent
protected java.util.Vector	evaluationListeners Container for the listeners to be notified of the start of a new evaluation.
protected static boolean	initialized
protected OrderedTable	internalFunctionTables Collection of elements in which we search for methods when a function-like (that is, an unqualified call or one prefixed with this) is evaluated and no corresponding function or method is found.
static java.lang.String[]	internalPrimitiveClassNames
static java.util.Hashtable	internalPrimitiveClassTable
protected antlr.Tokenizer	lexer
protected LocalClassLocator	localClasses
protected EvaluatorManager	manager
protected Options	options Container for the options governing the creation and run-time behavior of this evaluator and associated objects.
protected ObjectDisplayFilter	output
protected omegaJavaGrammar	parser
static java.lang.Class[]	primitive_classes The classes representing the primtive types in Java
static java.util.Hashtable	primitiveClasses
static java.lang.String[]	PrimitiveClassNames Then names of the different classes that mirror the primitives
static java.lang.String[]	primitiveTypeNames The names of the different primitive entitites in Java.
static java.util.Hashtable	primitiveTypes
static java.util.Hashtable	reversePrimitiveTypes
static boolean	ShowMultipleClasses Controls whether to search for multiple classes when resolving a partially qualified class name.
protected java.util.Stack	sourceStack
protected java.io.PrintWriter	stderr
protected java.io.PrintWriter	stdout
protected java.util.Vector	SubEvaluationListeners Container for listeners to be notified of all evaluation events , including all sub-expression being evaluated.
protected java.util.Vector	taskHistory
protected ExpressionInt	toplevelExpression Stores the currently active top-level task expression being evaluated.
protected java.util.Vector	warningMessages

Fields inherited from interface org.omegahat.Environment.Interpreter.Evaluator

ThisVariableName

Constructor Summary

	BasicEvaluator() Default constructor which uses the default options (usually read from the file OmegaOptions).
protected	BasicEvaluator(Evaluator ev) Creates an evaluator using the characteristics of the specified "parent" evaluator.
	BasicEvaluator(EvaluatorManager mgr) Creates an evaluator by attempting to copy the options from the default Evaluator available from the EvaluatorManager, and registers itself with that manager.
	BasicEvaluator(Options opts) Creates the evaluator with a reference to a collection of options controlling its characteristics.

Method Summary

int	addEvaluationListener(EvaluationListener l) Register a listener to be notified of the different evaluation events, such as the start and completion of a top-level evaluation, of starting the evaluation of a node in the parse tree, an error, etc.
int	addFunctionTable(java.lang.Object source) Register an object or class as a potential source of function-like methods that can be called from unqualified function-like calls.
int	addFunctionTable(java.lang.Object source, java.lang.String name)
boolean	addMethod(Method method, Name name)
java.lang.Object	addSourceInput(java.lang.Object description)
Task	addToHistory(java.lang.Object expr, java.lang.Object obj, java.lang.String command)
boolean	allowUnrestrictedAccess() Indicate whether access to methods and fields that are not usually accessible (non-public classes and/or methods and fields) are tolerated.
boolean	allowUnrestrictedAccess(boolean val)
java.lang.Object	asObject(Name name)
java.lang.Object	asObject(Name name, int max_num_components)
java.lang.Object	asObject(Name name, int max_num_components, boolean getClass) Resolves the object in the evaluation model identified by the first max_num_components elements of the name argument.
java.lang.String	asObjectName(Name name)
java.lang.Class	asPrimitiveClass(java.lang.String name) Return the primitive class (that is, double, int, etc.) corresponding the specified string of the form "double", etc.
boolean	assign(java.lang.String name, java.lang.Object obj) Assign the value to the specified variable name in the default database.
boolean	assign(java.lang.String name, java.lang.Object obj, Database db) Bind the value of obj to the variable called name in the specified databases.
boolean	assign(java.lang.String name, java.lang.Object obj, int which) Assign the value of the object to the specified variable name in the database identified by the index in the search path.
java.io.PrintWriter	asWriter(java.io.OutputStream str) Converts an OutputStream to a writer object that we can use println()
AttachedDatabase	attach(Database db) Add the specified database to the evaluator's search path using the default attachment position which is governed by
AttachedDatabase	attach(Database db, int idx) Attach the given database at the specified position in the evaluator's search path.
AttachedDatabase	attach(java.io.File name) Construct a database associated with the given file and attach it to the search path.
AttachedDatabase	attach(java.io.File name, int idx) Constructs a databases associated with the file (either a previously serialized database or a directory containing objects) and attach it to the search path in the specified position.
AttachedDatabase	attach(java.lang.String name) Creates and attaches a new database (of the default class) into the search path at the default position, specified by the value
AttachedDatabase	attach(java.lang.String name, int idx) Create a database using the default class and give it the specified name and attach it a the position idx in the search path.
AttachedDatabase	attach(java.net.URL u) Intended to attach the URL which is a jar or zip file as a database.
protected static java.util.Hashtable	classInit()
ClassLocatorInt	classLists()
protected ClassLocatorInt	classLists(ClassLocatorInt tb)
java.util.Vector	classPath() Compute the classpath for the application.
java.util.Vector	classPath(java.lang.String path)
java.lang.String[]	commandLine()
java.lang.Object	convertPrimitive(java.lang.Object value, java.lang.Class target) Convert an object to a primitive object such as an Integer to a Double or vice-versa.
java.lang.Object	copy(java.lang.Object o) Attempts to obtain a copy of the object by calling a constructor for that class that takes an object of the same class, or if that fails serializing the object and reading it back.
java.lang.Object	copy(java.lang.Object o, boolean deep)
java.lang.Object	copyByConstructor(java.lang.Object o, boolean deep) Attempts to "copy" the specified object by invoking a constructor in the class of the argument that takes a single argument of the same class.
java.lang.Object	copyBySerialization(java.lang.Object o) Perform a deep copy of the specified object by serializing its contents and reading them back.
ClassLocatorInt	createClassLists()
ExpressionInt	currentExpression() Returns the currently active sub-expression that is being evaluated as part of the active task.
ExpressionInt	currentExpression(ExpressionInt e) Sets the currently active sub-expression being evaluated at this moment.
java.lang.Object	data() Retrieve the user-level data.
java.lang.Object	data(java.lang.Object val) Set the user-level data.
Database	database()
Database	database(int index)
Database	database(java.lang.String name)
boolean	Debug()
boolean	Debug(boolean v)
boolean	Debug(java.lang.Boolean v)
boolean	Debug(java.lang.Object o)
boolean	Debug(java.lang.String val)
Debugger	debugger() Return the debugger object being used by this evaluator.
Debugger	debugger(Debugger d) Set the default debugger instance to be used by this evaluator.
Database	defaultDatabase() Retrieve the database into which assignments are made by default (i.e.
Database	defaultDatabase(boolean force) Get the default database to which assignments will be made.
Database	defaultDatabase(Database db) Set the database to which assignments are made by default.
ErrorHandler	defaultErrorHandler()
int	detach(Database db) Remove the specified database from the search path.
int	detach(int which) Remove the database in the specified position of the searchpath.
boolean	displayTask(java.lang.Object parsed_tree, java.lang.Object result, java.lang.String input)
boolean	displayTask(Task task)
int	displayWarnings()
int	displayWarnings(int n)
DynamicClassLoader	dynamicClassLoader()
DynamicClassLoader	dynamicClassLoader(DynamicClassLoader loader)
void	endSource()
void	endSource(java.lang.String msg)
void	endSource(java.lang.String msg, boolean silent)
void	endTaskEvaluation(ExpressionInt expr) Method called when a top-level task has been completed.
java.lang.Exception	error(java.lang.String msg) Signal an error, using the error message to indicate why.
java.lang.Exception	error(java.lang.Throwable e, java.lang.String msg) Raise an error based on the exception that was caught during the evaluation of the current top-level task.
ErrorHandler	errorHandler()
ErrorHandler	errorHandler(ErrorHandler e)
java.lang.Object	evaluate(ExpressionInt expr) Evaluate a top-level expression, notifying listeners when it has started and finished and displaying any warnings that arise.
java.lang.Object	evaluate(java.lang.Object expr, java.lang.String input)
java.lang.Object	evaluate(java.lang.String input)
java.lang.Object	evaluate(Task task) Evaluate a top-level task expression, storing the result in the Task object.
boolean	evaluationError(java.lang.Throwable e) Handle errors during a top-level task evaluation by handing it to the registered debugger, if one exists, or using the default error handler.
java.util.Vector	evaluationListeners() Returns the collection of registered listeners and initializes the Vector if it has not been previously created.
java.util.Vector	evaluationListeners(boolean force) Return the collection of current evaluation listeners or the container
java.util.Vector	evaluationListeners(java.util.Vector v) Sets the (potentially empty) container for the listener objects which are notified This is usually called with an empty, but initialized Vector object when it is needed, e.g.
boolean	exists(java.lang.String name) Determines whether a variable with the specified name exists in any of the databases in the search path.
void	exit() Default exit.
void	exit(int val) Terminate the session as quickly as possibly
java.lang.String	expandClassName(java.lang.String name)
java.lang.String	expandedClassPathElement(java.lang.String el, java.lang.Object base) Used when constructing the classpath elements, specifically when running via the java -jar option.
protected Database[]	find(java.lang.String name, boolean all)
java.lang.Object	findAsField(Name name, int max_num_components, boolean getClass)
java.lang.Class	findClass(Name name) Find the Class object corresponding to a multi-component Name object.
java.lang.Class	findClass(java.lang.String name) Locate a Class object with the given name, using incomplete matching such as Vector or util.Vector to resolve Vector.
java.lang.Class	findClass(java.lang.String name, boolean internalPrimitives) Primarily used for the dynamic compiler to allow for lookup up primitive classes by their internal names.
java.lang.Class	findClass(java.lang.String name, int error) Version of findClass that is used for interactive use where we don't want to put a try-catch clause around this but we don't want to get errors when the class is not found.
Function	findFunction(java.lang.String name)
Evaluable	findFunctionOrMethod(java.lang.String name)
OrderedTable	functionTableList() Retrieve the collection of objects in which we can potentially find internal function-like methods.
java.lang.Object	get(Name name)
java.lang.Object	get(NameTypeSearchFilter filter)
java.lang.Object	get(java.lang.String name)
java.lang.Object	get(java.lang.String name, boolean evaluate)
java.lang.Object	get(java.lang.String name, boolean evaluate, boolean strip)
java.lang.Object	get(java.lang.String name, java.lang.Class type)
java.lang.Object	get(java.lang.String name, java.lang.Class type, boolean strict) Searches for an object named @name which is an instance of the class specified by the argument @type.
java.lang.Object	get(java.lang.String name, java.lang.String type) This is a convenience function that calls get(String,Class,boolean).
java.lang.Object	get(java.lang.String name, java.lang.String type, boolean strict)
java.lang.Object	getBaseURL(java.lang.String el) Computes the parent of a file or URL object.
EvaluationEvent	getEvaluationEvent() Accessor for evaluationEvent field
java.util.Vector	getEvaluationListeners() Accessor for evaluationListeners field
java.lang.Object	getField(java.lang.String name, java.lang.Object obj, boolean getClass)
java.util.Vector	getSubEvaluationListeners() Accessor for SubEvaluationListeners field
java.lang.Object	help() Creates the default help system.
ClassList	Import(java.io.File f)
ClassList	Import(Name n) Creates a ClassList of the appropriate type for the sub-directory specified in the argument n
ClassList	Import(java.net.URL u)
void	init() Initializes this object so that it can be used to evaluate expressions.
boolean	initialize(Evaluator ev) Initializes this evaluator by copying/referencing the different components of the parent evaluator.
void	initTaskEvaluation(ExpressionInt expr) Method called when a new task expression is just about to be evaluated.
protected OrderedTable	internalFunctionTables(OrderedTable list) Internal method for controlling the list of sources in which we look for function-like methods.
static boolean	isPrimitive(java.lang.Class c)
static boolean	isPrimitive(java.lang.Object o)
int	javaVersion()
antlr.Tokenizer	lexer()
antlr.Tokenizer	lexer(java.io.Reader reader)
antlr.Tokenizer	lexer(antlr.Tokenizer lex)
LocalClassLocator	localClasses() the object that determines what classes the evaluator can locate.
LocalClassLocator	localClasses(LocalClassLocator l)
EvaluatorManager	manager() Retrieve the manager under whose nominal control the object is.
EvaluatorManager	manager(EvaluatorManager m) Set the manager which "controls" this object.
Database	newDatabase()
Database	newDatabase(java.lang.String name)
int	notifyListeners(ExpressionInt e) Notify the listeners that the given sub-expression is about to be evaluated.
int	notifyListeners(ExpressionInt e, boolean task) Notify the evaluation listeners that the given expression is about to be evaluated as a top-level task or as a sub-expression, depending on whether task is true or false.
java.lang.String[]	objects()
java.lang.String[]	objects(Database db)
java.lang.String[]	objects(int index)
Options	options() Get the current Options object in effect for this evaluator.
Options	options(Options opts) Set the Options object for the evaluator.
ObjectDisplayFilter	output()
ObjectDisplayFilter	output(boolean force)
ObjectDisplayFilter	output(ObjectDisplayFilter src)
ExpressionInt	parse(omegaJavaGrammar parser)
ExpressionInt	parse(java.io.Reader reader) Parse the contents of the text available on the specified reader.
ExpressionInt	parse(java.lang.String input)
ExpressionInt	parse(antlr.Tokenizer lexer)
omegaJavaGrammar	parser(antlr.Tokenizer lexer)
static java.lang.Class	primitiveClass(java.lang.Object o)
boolean	q()
boolean	q(boolean force)
boolean	remove(java.lang.String name) Discards the variable identified by name in the first database containing such a variable.
boolean	remove(java.lang.String name, Database db) Discards the specified variable in the particular database.
boolean	remove(java.lang.String name, int which) Remove the specified variable (identified by name) in the database identified by the index in the search path.
boolean	removeFunctionTable(java.lang.Object o) Remove a previously registered object that is considered as a potential source of function-like methods available to the scripting language with an `unqualified' call.
void	run() Basic method that allows this evaluator to be run in a thread.
boolean	same(java.lang.Object x, java.lang.Object y) Utility method for comparing two objects by reference.
java.lang.Class	searchForClass(java.lang.String name)
SearchPath	searchPath()
SearchPath	searchPath(SearchPath dbs)
SearchPath	searchPath(SearchPath dbs, boolean copy)
SearchPath	searchPath(java.util.Vector dbs)
EvaluationEvent	setEvaluationEvent(EvaluationEvent value) Accessor for setting evaluationEvent field
java.util.Vector	setEvaluationListeners(java.util.Vector value) Accessor for setting evaluationListeners field
java.util.Vector	setSubEvaluationListeners(java.util.Vector value) Accessor for setting SubEvaluationListeners field
java.lang.Object	show() Print a new line.
java.lang.Object	show(java.lang.Object obj)
java.lang.Object	show(java.lang.Object obj, boolean newline)
java.lang.Object	source(ArchiveEntry entry)
java.lang.Object	source(java.io.File f) Evaluate the contents of the specified file.
java.lang.Object	source(InputFileInt f) Evaluate the contents of the specified "file" (regular file or jar entry) as Omegahat commands.
java.lang.Object	source(java.lang.Object obj) Read evaluable input from an arbitrary object in a manner suitable for its class (including throwing an exception).
java.lang.Object	source(java.io.Reader reader)
java.lang.Object	source(java.io.Reader reader, java.lang.Object desc)
java.lang.Object	source(java.lang.String text) Read and evaluate input from a string, by attempting to treat it as a URL, a File and then an expression.
java.lang.Object	source(java.lang.String text, boolean asText)
java.lang.Object	source(java.net.URL u) Parse contents of URL.
java.util.Stack	sourceStack() Retrieve the stack detailing the ordered list of input sources currently active.
java.io.PrintWriter	stderr() Return the current error output device.
java.io.PrintWriter	stderr(java.io.OutputStream str)
java.io.PrintWriter	stdout() Return the current output device.
java.io.PrintWriter	stdout(java.io.OutputStream str)
java.util.Vector	taskHistory()
java.util.Vector	taskHistory(java.util.Vector v)
ExpressionInt	toplevelExpression() Returns the currently active top-level task expression.
ExpressionInt	toplevelExpression(ExpressionInt e) Sets the currently active top-level task expression.
boolean	useLazyEvaluation()
void	warning(java.lang.String msg) Register the specified warning message to be displayed at a suitable time, usually when the active task has been completed.
void	warning(java.lang.String msg, boolean immediate)
void	warning(java.lang.Throwable e, java.lang.String msg) Issue a warning about the exception that was caught at some point in the evaluation of the current task.
java.util.Vector	warnings()
java.util.Vector	warnings(java.util.Vector v)
Database[]	where(java.lang.String name)
Database	which(Name name)
Database	which(java.lang.String name) Identifies the first database in the evaluator's search path in which a variable with this name can be found

Methods inherited from class java.lang.Object

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

Field Detail

primitive_classes

public static final java.lang.Class[] primitive_classes

The classes representing the primtive types in Java

primitiveTypeNames

public static final java.lang.String[] primitiveTypeNames

The names of the different primitive entitites in Java.

PrimitiveClassNames

public static final java.lang.String[] PrimitiveClassNames

Then names of the different classes that mirror the primitives

internalPrimitiveClassNames

public static final java.lang.String[] internalPrimitiveClassNames

ShowMultipleClasses

public static boolean ShowMultipleClasses

Controls whether to search for multiple classes when resolving a partially qualified class name. This could be made evaluator-instance specific.

See Also:

findClass(java.lang.String), #findClasses(java.lang.String)

initialized

protected static boolean initialized

primitiveClasses

public static java.util.Hashtable primitiveClasses

primitiveTypes

public static java.util.Hashtable primitiveTypes

internalPrimitiveClassTable

public static java.util.Hashtable internalPrimitiveClassTable

reversePrimitiveTypes

public static java.util.Hashtable reversePrimitiveTypes

options

protected Options options

Container for the options governing the creation and run-time behavior of this evaluator and associated objects. This contains information such as the name of the default database class, the prompt, etc.

databases

protected SearchPath databases

Ordered container of databases in which omegahat variables are stored and the evaluation of expressions looks for referenced variables. The elements are arbitrary objects that implement the Database interface.

data

protected java.lang.Object data

User-specifiable data that can be retrieved by the different expressions as they are evaluated without having to supply the information as an argument. This is a short-cut for augmenting the information available to the expression objects without having to extend them, the parser or the evaluator class.

DefaultAttachIndex

protected int DefaultAttachIndex

The default position into which databases are added to the search path. This controls how variables are found in newly attached databases.

toplevelExpression

protected ExpressionInt toplevelExpression

Stores the currently active top-level task expression being evaluated.

lexer

protected antlr.Tokenizer lexer

parser

protected omegaJavaGrammar parser

output

protected ObjectDisplayFilter output

taskHistory

protected java.util.Vector taskHistory

defaultDatabase

protected Database defaultDatabase

errorHandler

protected ErrorHandler errorHandler

warningMessages

protected java.util.Vector warningMessages

class_lists

protected ClassLocatorInt class_lists

localClasses

protected LocalClassLocator localClasses

dynamicClassLoader

protected DynamicClassLoader dynamicClassLoader

manager

protected EvaluatorManager manager

stderr

protected java.io.PrintWriter stderr

stdout

protected java.io.PrintWriter stdout

currentExpression

protected ExpressionInt currentExpression

Stores the sub-expression within the expression tree that is currently being evaluated.

debugger

protected Debugger debugger

The object to use for debugging errors as they arise in the evaluation of expressions by this evaluator.

evaluationListeners

protected java.util.Vector evaluationListeners

Container for the listeners to be notified of the start of a new evaluation.

SubEvaluationListeners

protected java.util.Vector SubEvaluationListeners

Container for listeners to be notified of all evaluation events , including all sub-expression being evaluated.

evaluationEvent

protected EvaluationEvent evaluationEvent

internalFunctionTables

protected OrderedTable internalFunctionTables

Collection of elements in which we search for methods when a function-like (that is, an unqualified call or one prefixed with this) is evaluated and no corresponding function or method is found.

allowUnrestrictedAccess

protected boolean allowUnrestrictedAccess

sourceStack

protected java.util.Stack sourceStack

Constructor Detail

BasicEvaluator

public BasicEvaluator(Options opts)

Creates the evaluator with a reference to a collection of options controlling its characteristics.

BasicEvaluator

public BasicEvaluator()

Default constructor which uses the default options (usually read from the file OmegaOptions).

BasicEvaluator

public BasicEvaluator(EvaluatorManager mgr)

Creates an evaluator by attempting to copy the options from the default Evaluator available from the EvaluatorManager, and registers itself with that manager.

BasicEvaluator

protected BasicEvaluator(