Package edu.mit.ai.psg.jevaES

JevaES is a core source code evaluator for Java expressions and statements; see JevaESUI for user interfaces.

See:
Description

Interface Summary

IEnv	IEnv: Interface to objects in which names can be looked up.
IExpressionNode	Interface to nodes for Java expressions.
IExpressionStoreNode	Expression nodes valid on left of assignment.
IJevaNode	IJevaNode: extends Node with methods for accessing the tokens and for printing out the token stream for this node.
IPackage	IPackage is an interface for internal representations of known packages to store and retrieve the classes defined within them.
IStatementNode	Interface to parse nodes for Java statements.
IStore	IStore: interface to implementation objects for a storable location for assignment.
JevaESParserConstants
JevaESParserTreeConstants
Node

Class Summary

AccessibilityMethods	AccessibilityMethods --- methods for checking whether IllegalAccessException should be thrown.
ASCII_UCodeESC_CharStream	An implementation of interface CharStream, where the stream is assumed to contain only ASCII characters (with java-like unicode escape processing).
ClassPathMethods	ClassPathMethods.findInClassPath searches classpath to obtain an input stream from either source directories or jar files; verifyPackageNameFromClassPath checks that a directory structure or jar file entry exists corresponding to a package name starting from some root in the class path.
ClassPathMethods.ClassPathSearchResult	Class for multiple value return of with found location path, input stream, and modification date
ClassPathMethods.StarFilenameFilter	Filter to match filenames based on pattern with *'s in it
EnvBase	A base class for Environment nodes that forwards all requests to the next environment node.
EnvEnd	A tail environment node that holds the root package.
EnvLocalStore	LocalStore implements storage for a local variable in an environment chain.
EnvOptionBits	EnvOptionBits -- environment which specifies option bits; can be used to override the options of the environment.
EvalMethods	Centralized static methods for evaluating nodes while catching exceptions.
ExpressionNode	A base class for Expressions which caches its type (and value if constant).
IEnv.ClassResult	class used for multiple value return.
JevaES	JevaES (Java Evaluator: Expressions & Statements) is the entry point class of the core of a source code evaluator for Java expressions and statements; see edu.mit.ai.psg.jevaESUI for user interfaces.
JevaESParser	JevaESParser: parse Java Expressions and Statements.
JevaESParserTokenManager
JevaNode	JevaNode: Extends SimpleNode so each node can echo back its token stream of Java code.
JNDImportDeclaration	JNDImportDeclaration: parse node for import declarations.
JNDPackageDeclaration	JNDPackageDeclaration: parse node for package declarations.
JNEAdditiveExpression	Jeva parse Node for binary + - Expressions [JavaLangSpec 1.0 sec 15.17 Additive Operators].
JNEAndExpression	Jeva parse Node for & Expressions [JavaLangSpec 1.0 sec 15.21 Bitwise and Logical Operators].
JNEArguments	JNEArguments: parse node for arguments for method call or constructor call.
JNEArrayAccessExpression	Jeva parse Node for array[index] Expressions [JavaLangSpec1.0 sec15.12 Array Access Expressions].
JNEArrayCreationExpression	Jeva parse Node for array creation Expressions: "new" Type [arraydims] or "new" Type [arraydims] { arrayinitializer }
JNEArrayDimensions	Jeva parse Node for dimensions in array creation Expressions.
JNEArrayInitializer	JNEArrayInitializer: parse node for array initializer in array creation expressions.
JNEAssignmentExpression	Jeva parse Nodes for all assignment Expressions (=, +=, *=, etc.) [JavaLangSpec1.0 sec 15.25].
JNEAssignmentOperator	Jeva parse Node for just assignment operator (=, +=, ...) in assignment Expressions.
JNECastExpression	Jeva parse Node for cast Expressions: (type) expr .
JNEConditionalAndExpression	Jeva parse Node for && Expressions.
JNEConditionalExpression	Jeva parse Node for ? : Expressions.
JNEConditionalOrExpression	Jeva parse Node for || Expressions.
JNEEqualityExpression	Jeva parse Node for == and != Expressions [JavaLangSpec 1.0 sec 15.20 Equality Operators].
JNEExclusiveOrExpression	Jeva parse Node for ^ Expressions [JavaLangSpec 1.0 sec 15.21 Bitwise and Logical Operators].
JNEInclusiveOrExpression	Jeva parse Node for | Expressions [JavaLangSpec 1.0 sec 15.21 Bitwise and Logical Operators].
JNEInstanceCreationExpression	Jeva parse Node for instance creation expressions: "new" Type(args...).
JNEInstanceOfExpression	Jeva parse Node for Expr instanceof Class [JavaLangSpec1.0 sec15.19.2 Type Comparison Operator instanceof]
JNELiteralExpression	Jeva parse node for literal expressions (1, 3.14, "Hi", etc.)
JNEMethodInvocationExpression	Jeva parse node for Method invocation expressions: target.method(args...) [JavaLangSpec 1.0 sec 15.11 Method Invocation Expressions].
JNEMultiplicativeExpression	Jeva parse Node for * % / Expressions [JavaLangSpec 1.0 sec 15.16 Multiplicative Operators].
JNEParenthesizedExpression	Jeva parse Node for (parenthesized expressions): This node exists to mark the beginning and end of the parenthesized expression so it can be reproduced in text (the "(" and ")" are not part of the expression they contain).
JNEPostfixExpression	Jeva parse node for postfix expressions (x++, x--).
JNEPreDecrementExpression	Jeva parse Node for --x Expressions.
JNEPreIncrementExpression	Jeva parse nodes for ++x expressions.
JNERelationalExpression	Jeva parse node for relational expressions (<,>,<=,>=) [JavaLangSpec 1.0 sec 15.19 Relational Operators]
JNEShiftExpression	Jeva parse Node for <<, >>, >>> expressions [JavaLangSpec 1.0 sec 15.18 Shift Operators].
JNEUnaryExpression	Jeva parse Node for unary expressions (!x, ~x, -x, +x) [Java Lang Spec 1.0 sec 15.14.3-6]
JNFormalParameter	Jeva parse Node for formal parameters of methods and constructors
JNName	Jeva parse node for names (including parameters, fields, and class names); A name x.y.z is parsed with nested names as (((x).y).z).
JNPrimitiveType	Jeva parse Node for primitive types (int, boolean, etc.)
JNResultType	Jeva parse Node for result types: "void" | Type().
JNSBlock	Jeva parse Node for block Statements: {...}
JNSBreakStatement	Jeva parse node for break Statements.
JNSContinueStatement	Jeva parse node for continue Statements.
JNSDoStatement	Jeva parse Node for do Statements.
JNSEmptyStatement	Jeva parse node for empty statements ";".
JNSExpressionStatement	Jeva parse Node for expression statements "(expr);".
JNSExpressionStatementList	Jeva parse Node for lists of expression statements, used in for statements' initialize and update clauses.
JNSForStatement	Jeva parse Node for for statements.
JNSIfStatement	Jeva parse Node for if Statements.
JNSLabeledStatement	Jeva parse Node for labeled statements e.g., "label: while(true){ ...
JNSLocalVariableDeclaration	Jeva parse Node for local variable declarations, e.g., "int i = 0;".
JNSReturnStatement	Jeva parse Node for return Statements.
JNSSwitchLabel	Jeva parse Node for labels within a switch Statement.
JNSSwitchStatement	Jeva parse Node for switch Statements [JavaLangSpec1.0sec14.9].
JNSSynchronizedStatement	Jeva parse Node for synchronized(expr) {...} statements
JNSThrowStatement	Jeva parse Node for throw Statements.
JNSTryStatement	Jeva parse Node for try Statements [JavaLangSpec1.0sec14.18]
JNSVariableDeclarator	Jeva parse Node for variable declators, a component in variable declaration statements and field declarations.
JNSWhileStatement	Jeva parse Node for while Statements.
JNType	Jeva parse Node for type nodes, except void. ( PrimitiveType() | Name() ) [ ArrayDims() ]
LeftAssociativeOperatorExpression	Shared implementation for left associative operators.
LiteralMethods	Methods for creating primitives from literal strings.
Package	Internal representation of packages, for name lookups.
PrimitiveOperations	Binary Operations on Primitive types (numbers and booleans) represented by their wrapper types (e.g., int represented by Integer).
SimpleNode	Root class for all parse tree nodes.
Token	Describes the input token stream.
TypeMethods	Predicates and Methods for testing and comparing types.

Exception Summary

AbruptCompletionException	Instances of subclasses of AbruptCompletionException are thrown to implement abrupt completion of statements via break, continue, return, or throw.
BreakException	BreakExceptions are thrown to implement abrupt completion of statements.
ContinueException	ContinueExceptions are thrown to implement abrupt completion of a loop body statement.
IllegalConstructException	IllegalConstructException is thrown when Jeva finds a construct used in an illegal context, e.g., using "this" in a static method, or is malformed, e.g., an array initializer with too many elements.
IllegalNameException	IllegalNameException is thrown when Jeva finds a name conflict, e.g., a name that has already been used or is ambiguous.
IllegalTypeException	IllegalTypeException is thrown when Jeva finds a type conflict.
ParseException	This exception is thrown when parse errors are encountered.
ReturnException	ReturnExceptions are thrown to implement abrupt completion of methods.
ThrowException	ThrowExceptions are thrown to implement thrown exceptions.
VerifyingException	Base class for exceptions for illegal nodes found during verification; saves node and environment where problem occurred.

Error Summary

EvaluatingError	Error used to capture context of internal errors thrown while evaluating.
TokenMgrError
VerifyingError	Error used to capture context of internal errors thrown while verifying types in source code.

Package edu.mit.ai.psg.jevaES Description

JevaES is a core source code evaluator for Java expressions and statements; see JevaESUI for user interfaces.

JevaES (Java Evaluator: Expressions & Statements) parses and evaluates Java expressions and statements, as specified in the Java Language Specification 1.0 and amended informally in Clarifications and Amendments to the JLS (in particular, final variables and .class expressions). JevaES does not accept class and interface declarations (nor expressions with anonymous classes). In addition, JevaES accepts import declarations (reduces verbose names) and package declarations (to enable access in packages).

Most uses will be through classes in the edu.mit.ai.psg.jevaESUI user interface package, which provides user interfaces which accept typed expressions and statements.

Programs that need to evaluate individual expressions and statements usually only need to call methods in the JevaES class, e.g.,
JevaES.parseEvalStringExpression(expressionString), or
JevaES.parseEvalStringStatement(statementString).
To separate parsing from evaluation, call
JevaES.parse...(..), then EvalMethods.evaluate(...), using JevaES.defaultEnv().

Hints

• Inner classes and interfaces from compiled libraries can be accessed through their renamed names, e.g., java.util.Map.Entry can be accessed through the name java.util.Map$Entry .
• Evaluating is much less expensive than parsing, so to evaluate the same expression with different values, evaluate it with different environments instead of constructing and parsing new strings. See DemoEvalWithEnv.

* * * Please read JevaES.copyright.

JevaES was developed using a parser generated by Sun's free Java parser generator JavaCC/JJTree (now maintained by the spinoff Metamata), using a modified version of the example Java grammar.