com.goldencode.expr

Class Scope

java.lang.Object

com.goldencode.expr.Scope

Direct Known Subclasses:

AbstractResource, NamedFunction, RuleContainer, SecurityManager

public abstract class Scope
extends java.lang.Object

Objects of this type are used by the SymbolResolver to partition library objects and user variables registered by clients of the expression engine. Whenever a worker library or user variable is registered, a Scope instance must be provided by the registering client. This instance is associated with the library or variable for the lifetime of the resolver.

When and expression is parsed and compiled, the resolver's current scope is requested via SymbolResolver.getCurrentScope(). The instance of Scope returned by that call is used as a key to resolve library and variable references as they are encountered in the expression. Only references contained within the current scope or within an enclosing scope (or within its enclosing scope, and so on...) are correctly resolved.

Scope is also used when resetting the values of variables in a variable pool.

See Also:

SymbolResolver.resetVariables(com.goldencode.expr.Scope, boolean)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	Scope.ScopeState A scope state, kept for each resolver.

Field Summary

Fields

Modifier and Type	Field and Description
private static java.util.function.Function<SymbolResolver,Scope.ScopeState>	NEW_STATE Function to create a new Scope.ScopeState for a resolver.
private java.util.Map<SymbolResolver,Scope.ScopeState>	resolverState A map of the scope state for each resolver.
private SymbolResolver	singleResolver The resolver instance, used as long as only one resolver associates this scope.
private Scope.ScopeState	singleState Singleton scope state.

Constructor Summary

Constructors

Constructor and Description
Scope()

Method Summary

Modifier and Type	Method and Description
abstract Scope	getEnclosingScope() This method must return the object which represents the scope context which encloses this scope, if this scope is nested within a broader scope.
java.util.Map<java.lang.String,java.lang.Object>	getLibraries(SymbolResolver sr, boolean create) Resolve the Scope.ScopeState.libraries map for the specified resolver.
java.util.Map<java.lang.Class<?>,java.lang.String>	getLibraryClasses(SymbolResolver sr, boolean create) Resolve the Scope.ScopeState.libraryClasses map for the specified resolver.
java.util.Map<java.lang.Class<?>,java.lang.Object>	getLibsByClass(SymbolResolver sr, boolean create) Resolve the Scope.ScopeState.libsByClass map for the specified resolver.
private Scope.ScopeState	getResolverState(SymbolResolver sr) Calculate the Scope.ScopeState associated with the given resolver.
Variable[]	getVariableList(SymbolResolver sr) Resolve the Scope.ScopeState.variableList array for the specified resolver.
java.util.Map<java.lang.String,Variable>	getVariables(SymbolResolver sr, boolean create) Resolve the Scope.ScopeState.variableList map for the specified resolver.

Methods inherited from class java.lang.Object

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

Field Detail

NEW_STATE

private static final java.util.function.Function<SymbolResolver,Scope.ScopeState> NEW_STATE

Function to create a new Scope.ScopeState for a resolver.

resolverState

private java.util.Map<SymbolResolver,Scope.ScopeState> resolverState

A map of the scope state for each resolver. Will be null as long as only one resolver uses this scope state.

singleState

private Scope.ScopeState singleState

Singleton scope state. Will be used until more than one resolver associates this scope- at that point, resolverState will be initialized and used.

singleResolver

private SymbolResolver singleResolver

The resolver instance, used as long as only one resolver associates this scope. After this, resolverState is used.

Constructor Detail

Scope

public Scope()

Method Detail

getEnclosingScope

public abstract Scope getEnclosingScope()

This method must return the object which represents the scope context which encloses this scope, if this scope is nested within a broader scope.

Returns:

Enclosing scope object, or null if this scope represents the broadest scope available.

getLibraries

public java.util.Map<java.lang.String,java.lang.Object> getLibraries(SymbolResolver sr,
                                                                     boolean create)

Resolve the Scope.ScopeState.libraries map for the specified resolver.

Parameters:

sr - The resolver which uses this scope.

create - Flag indicating to create a new instance if one is not created yet.

Returns:

The Scope.ScopeState.libraries map.

getVariables

public java.util.Map<java.lang.String,Variable> getVariables(SymbolResolver sr,
                                                             boolean create)

Resolve the Scope.ScopeState.variableList map for the specified resolver.

Parameters:

sr - The resolver which uses this scope.

create - Flag indicating to create a new instance if one is not created yet.

Returns:

The Scope.ScopeState.variableList map.

getLibsByClass

public java.util.Map<java.lang.Class<?>,java.lang.Object> getLibsByClass(SymbolResolver sr,
                                                                         boolean create)

Resolve the Scope.ScopeState.libsByClass map for the specified resolver.

Parameters:

sr - The resolver which uses this scope.

create - Flag indicating to create a new instance if one is not created yet.

Returns:

The Scope.ScopeState.libsByClass map.

getLibraryClasses

public java.util.Map<java.lang.Class<?>,java.lang.String> getLibraryClasses(SymbolResolver sr,
                                                                            boolean create)

Resolve the Scope.ScopeState.libraryClasses map for the specified resolver.

Parameters:

sr - The resolver which uses this scope.

create - Flag indicating to create a new instance if one is not created yet.

Returns:

The Scope.ScopeState.libraryClasses map.

getVariableList

public Variable[] getVariableList(SymbolResolver sr)

Resolve the Scope.ScopeState.variableList array for the specified resolver.

Parameters:

sr - The resolver which uses this scope.

Returns:

The Scope.ScopeState.variableList array.

getResolverState

private Scope.ScopeState getResolverState(SymbolResolver sr)

Calculate the Scope.ScopeState associated with the given resolver.

If singleState is not yet set or the singleResolver is the same as the received one, keep the 'singleton' mode and use singleResolver and singleState.

Otherwise, switch to a dynamic approach where resolverState map keeps the scope state for each resolver.

Parameters:

sr - The resolve which uses this scope.

Returns:

The scope state for the specified resolver.