bsh

Class NameSpace

Implemented Interfaces:
java.io.Serializable, BshClassManager.Listener, NameSource

public class NameSpace
extends java.lang.Object
implements java.io.Serializable, BshClassManager.Listener, NameSource

A namespace in which methods, variables, and imports (class names) live. This is package public because it is used in the implementation of some bsh commands. However for normal use you should be using methods on bsh.Interpreter to interact with your scripts.

A bsh.This object is a thin layer over a NameSpace that associates it with an Interpreter instance. Together they comprise a Bsh scripted object context.

Note: I'd really like to use collections here, but we have to keep this compatible with JDK1.1

See Also:
Serialized Form

Field Summary

static NameSpace
JAVACODE
String
nsName
The name of this namespace.

Constructor Summary

NameSpace(BshClassManager classManager, String name)
NameSpace(NameSpace parent, String name)
NameSpace(NameSpace parent, BshClassManager classManager, String name)

Method Summary

void
addNameSourceListener(NameSource.Listener listener)
Implements NameSource Add a listener who is notified upon changes to names in this space.
protected void
checkMethodModifiers(BshMethod method)
protected void
checkVariableModifiers(String name, bsh.Modifiers modifiers)
Dissallow static vars outside of a class
void
classLoaderChanged()
Clear all cached classes and names
void
clear()
Clear all variables, methods, and imports from this namespace.
void
doSuperImport()
Perform "import *;" causing the entire classpath to be mapped.
Object
get(String name, Interpreter interpreter)
Resolve name to an object through this namespace.
String[]
getAllNames()
Implements NameSource
protected void
getAllNamesAux(Vector vec)
Helper for implementing NameSource
static Object
getAssignableForm(Object rhs, Class lhsType)
Determine if the RHS object can be assigned to the LHS type:

1) As in a legal Java assignment (as determined by Reflect.isJavaAssignable()) through widening or promotion

2) Via special BeanShell extensions like interface generation or (gag) numeric-style promotion of primitive wrappers (e.g.

Class
getClass(String name)
Load a class through this namespace taking into account imports.
BshClassManager
getClassManager()
Object
getCommand(String name, Class[] argTypes, Interpreter interpreter)
A command is a scripted method or compiled command class implementing a specified method signature.
NameSpace
getGlobal()
Get the top level namespace or this namespace if we are the top.
int
getInvocationLine()
String
getInvocationText()
BshMethod
getMethod(String name, Class[] sig)
Get the bsh method matching the specified signature declared in this name space or a parent.
String[]
getMethodNames()
Get the names of methods defined in this namespace.
BshMethod[]
getMethods()
Get the methods defined in this namespace.
String
getName()
NameSpace
getParent()
Get the parent namespace.
NameSpace
getSuper()
Get the parent namespace or this namespace if we are the top.
Object
getVariable(String name)
Get the specified variable in this namespace or a parent namespace.
Object
getVariable(String name, boolean recurse)
Get the specified variable in this namespace.
protected bsh.NameSpace.Variable
getVariableImpl(String name, boolean recurse)
Locate a variable and return the Variable object with optional recursion through parent name spaces.
String[]
getVariableNames()
Get the names of variables defined in this namespace.
static Class
identifierToClass(ClassIdentifier ci)
This is a helper method for working inside of bsh scripts and commands.
void
importClass(String name)
Import a class name.
void
importCommands(String name)
Import scripted or compiled BeanShell commands in the following package in the classpath.
void
importPackage(String name)
subsequent imports override earlier ones
Object
invokeMethod(String methodName, Object[] args, Interpreter interpreter)
Invoke a method in this namespace with the specified args and interpreter reference.
Object
invokeMethod(String methodName, Object[] args, Interpreter interpreter, CallStack callstack, bsh.SimpleNode callerInfo)
This method simply delegates to This.invokeMethod();

protected boolean
isVisible(BshMethod method)
This is a hook to allow ClassNameSpace to add functionality to getMethod()
protected boolean
isVisible(bsh.NameSpace.Variable var)
This is a hook to allow ClassNameSpace to add functionality here.
void
loadDefaultImports()
Import standard packages.
void
nameSpaceChanged()
Clear all cached classes and names
void
prune()
Used for serialization
void
setMethod(String name, BshMethod method)
Note: this is primarily for internal use.
void
setName(String name)
void
setParent(NameSpace parent)
void
setTypedVariable(String name, Class type, Object value, boolean isFinal)
Deprecated. See #setTypedVariable( String, Class, Object, Modifiers )
void
setTypedVariable(String name, Class type, Object value, bsh.Modifiers modifiers)
Declare a variable in the local scope and set its initial value.
void
setVariable(String name, Object value, boolean strictJava)
Set the variable through this namespace.
String
toString()
void
unsetVariable(String name)
Remove the variable from the namespace.
protected Object
unwrapVariable(bsh.NameSpace.Variable var)
Unwrap a variable to its value.

Field Details

JAVACODE

public static final NameSpace JAVACODE

nsName

public String nsName
The name of this namespace. If the namespace is a method body namespace then this is the name of the method. If it's a class or class instance then it's the name of the class.

Constructor Details

NameSpace

public NameSpace(BshClassManager classManager,
                 String name)

NameSpace

public NameSpace(NameSpace parent,
                 String name)

NameSpace

public NameSpace(NameSpace parent,
                 BshClassManager classManager,
                 String name)

Method Details

addNameSourceListener

public void addNameSourceListener(NameSource.Listener listener)
Implements NameSource Add a listener who is notified upon changes to names in this space.
Specified by:
addNameSourceListener in interface NameSource

checkMethodModifiers

protected void checkMethodModifiers(BshMethod method)
            throws UtilEvalError

checkVariableModifiers

protected void checkVariableModifiers(String name,
                                      bsh.Modifiers modifiers)
            throws UtilEvalError
Dissallow static vars outside of a class
Parameters:
name - is here just to allow the error message to use it

classLoaderChanged

public void classLoaderChanged()
Clear all cached classes and names
Specified by:
classLoaderChanged in interface BshClassManager.Listener

clear

public void clear()
Clear all variables, methods, and imports from this namespace. If this namespace is the root, it will be reset to the default imports.

doSuperImport

public void doSuperImport()
            throws UtilEvalError
Perform "import *;" causing the entire classpath to be mapped. This can take a while.

get

public Object get(String name,
                  Interpreter interpreter)
            throws UtilEvalError
Resolve name to an object through this namespace.

getAllNames

public String[] getAllNames()
Implements NameSource
Specified by:
getAllNames in interface NameSource
Returns:
all variable and method names in this and all parent namespaces

getAllNamesAux

protected void getAllNamesAux(Vector vec)
Helper for implementing NameSource

getAssignableForm

public static Object getAssignableForm(Object rhs,
                                       Class lhsType)
            throws UtilEvalError
Determine if the RHS object can be assigned to the LHS type:

1) As in a legal Java assignment (as determined by Reflect.isJavaAssignable()) through widening or promotion

2) Via special BeanShell extensions like interface generation or (gag) numeric-style promotion of primitive wrappers (e.g. Short to Integer).

If the assignment is legal in BeanShell return the assignable form of the RHS.

This method is used in many places throughout bsh including assignment operations and method selection.

In normal cases this functions as a simple check for assignability and the value is returned unchanged. e.g. a String is assignable to an Object, but no conversion is necessary. Similarly an int is assignable to a long, so no conversion is done. In this sense assignability is in terms of what the Java reflection API will allow since the reflection api will do widening conversions in the case of sets on fields and arrays. (CLARIFY: what about method args?)

The primary purpose of the "returning the assignable form" abstraction is to allow non-standard Java assignment conversions. e.g. wrapper conversion for boxing and unboxing. Some of this will be considered standard in Java 1.5.

Parameters:
rhs - is a value, bsh.Primitive wrapper, or Primitive.NULL. If it is a Primitive wrapper it will be unwrapped and compared using Reflect.isJavaAssignableFrom(). If it is Primtive.VOID an error will occur.
lhsType - lhsType is a real Java class type or Java primitive TYPE
Returns:
an assignable form of the rhs, usually the original rhs if assignable. If the rhs was a Primitive and it was assignable the Primitive will be returned. If the Primitive needed to be auto-boxed to a wrapper type, the wrapper type will be returned.
Throws:
UtilEvalError - if the assignment cannot be made legally
UtilEvalError - on rhs of Primitive.VOID (void assignment)
See Also:
BSHCastExpression.castObject( java.lang.Object, java.lang.Class )

getClass

public Class getClass(String name)
            throws UtilEvalError
Load a class through this namespace taking into account imports. The class search will proceed through the parent namespaces if necessary.
Returns:
null if not found.

getClassManager

public BshClassManager getClassManager()

getCommand

public Object getCommand(String name,
                         Class[] argTypes,
                         Interpreter interpreter)
            throws UtilEvalError
A command is a scripted method or compiled command class implementing a specified method signature. Commands are loaded from the classpath and may be imported using the importCommands() method.

This method searches the imported commands packages for a script or command object corresponding to the name of the method. If it is a script the script is sourced into this namespace and the BshMethod for the requested signature is returned. If it is a compiled class the class is returned. (Compiled command classes implement static invoke() methods).

The imported packages are searched in reverse order, so that later imports take priority. Currently only the first object (script or class) with the appropriate name is checked. If another, overloaded form, is located in another package it will not currently be found. This could be fixed.

Parameters:
name - is the name of the desired command method
argTypes - is the signature of the desired command method.
Returns:
a BshMethod, Class, or null if no such command is found.
Throws:
UtilEvalError - if loadScriptedCommand throws UtilEvalError i.e. on errors loading a script that was found

getGlobal

public NameSpace getGlobal()
Get the top level namespace or this namespace if we are the top. Note: this method should probably return type bsh.This to be consistent with getThis();

getInvocationLine

public int getInvocationLine()

getInvocationText

public String getInvocationText()

getMethod

public BshMethod getMethod(String name,
                           Class[] sig)
            throws UtilEvalError
Get the bsh method matching the specified signature declared in this name space or a parent.

Note: this method is primarily intended for use internally. If you use this method outside of the bsh package you will have to be familiar with BeanShell's use of the Primitive wrapper class.

Returns:
the BshMethod or null if not found
See Also:
Primitive

getMethodNames

public String[] getMethodNames()
Get the names of methods defined in this namespace. (This does not show methods in parent namespaces).

getMethods

public BshMethod[] getMethods()
Get the methods defined in this namespace. (This does not show methods in parent namespaces).

getName

public String getName()

getParent

public NameSpace getParent()
Get the parent namespace. Note: this isn't quite the same as getSuper(). getSuper() returns 'this' if we are at the root namespace.

getSuper

public NameSpace getSuper()
Get the parent namespace or this namespace if we are the top. Note: this method should probably return type bsh.This to be consistent with getThis();

getVariable

public Object getVariable(String name)
            throws UtilEvalError
Get the specified variable in this namespace or a parent namespace.

Note: this method is primarily intended for use internally. If you use this method outside of the bsh package you will have to use Primitive.unwrap() to get primitive values.

Returns:
The variable value or Primitive.VOID if it is not defined.

getVariable

public Object getVariable(String name,
                          boolean recurse)
            throws UtilEvalError
Get the specified variable in this namespace.
Parameters:
recurse - If recurse is true then we recursively search through parent namespaces for the variable.

Note: this method is primarily intended for use internally. If you use this method outside of the bsh package you will have to use Primitive.unwrap() to get primitive values.

Returns:
The variable value or Primitive.VOID if it is not defined.

getVariableImpl

protected bsh.NameSpace.Variable getVariableImpl(String name,
                                                 boolean recurse)
            throws UtilEvalError
Locate a variable and return the Variable object with optional recursion through parent name spaces.

If this namespace is static, return only static variables.

Returns:
the Variable value or null if it is not defined

getVariableNames

public String[] getVariableNames()
Get the names of variables defined in this namespace. (This does not show variables in parent namespaces).

identifierToClass

public static Class identifierToClass(ClassIdentifier ci)
This is a helper method for working inside of bsh scripts and commands. In that context it is impossible to see a ClassIdentifier object for what it is. Attempting to access a method on a ClassIdentifier will look like a static method invocation. This method is in NameSpace for convenience (you don't have to import bsh.ClassIdentifier to use it );

importClass

public void importClass(String name)
Import a class name. Subsequent imports override earlier ones

importCommands

public void importCommands(String name)
Import scripted or compiled BeanShell commands in the following package in the classpath. You may use either "/" path or "." package notation. e.g. importCommands("/bsh/commands") or importCommands("bsh.commands") are equivalent. If a relative path style specifier is used then it is made into an absolute path by prepending "/".

importPackage

public void importPackage(String name)
subsequent imports override earlier ones

invokeMethod

public Object invokeMethod(String methodName,
                           Object[] args,
                           Interpreter interpreter)
            throws EvalError
Invoke a method in this namespace with the specified args and interpreter reference. No caller information or call stack is required. The method will appear as if called externally from Java.

See Also:
bsh.This.invokeMethod( String methodName, Object [] args, Interpreter interpreter, CallStack callstack, SimpleNode callerInfo )

invokeMethod

public Object invokeMethod(String methodName,
                           Object[] args,
                           Interpreter interpreter,
                           CallStack callstack,
                           bsh.SimpleNode callerInfo)
            throws EvalError
This method simply delegates to This.invokeMethod();

See Also:
bsh.This.invokeMethod( String methodName, Object [] args, Interpreter interpreter, CallStack callstack, SimpleNode callerInfo )

isVisible

protected boolean isVisible(BshMethod method)
            throws UtilEvalError
This is a hook to allow ClassNameSpace to add functionality to getMethod()

isVisible

protected boolean isVisible(bsh.NameSpace.Variable var)
            throws UtilEvalError
This is a hook to allow ClassNameSpace to add functionality here.

loadDefaultImports

public void loadDefaultImports()
Import standard packages. Currently:
importClass("bsh.EvalError");
importClass("bsh.Interpreter");
importPackage("javax.swing.event");
importPackage("javax.swing");
importPackage("java.awt.event");
importPackage("java.awt");
importPackage("java.net");
importPackage("java.util");
importPackage("java.io");
importPackage("java.lang");
importCommands("/bsh/commands");

nameSpaceChanged

public void nameSpaceChanged()
Clear all cached classes and names

prune

public void prune()
Used for serialization

setMethod

public void setMethod(String name,
                      BshMethod method)
            throws UtilEvalError
Note: this is primarily for internal use.

setName

public void setName(String name)

setParent

public void setParent(NameSpace parent)

setTypedVariable

public void setTypedVariable(String name,
                             Class type,
                             Object value,
                             boolean isFinal)
            throws UtilEvalError

Deprecated. See #setTypedVariable( String, Class, Object, Modifiers )


setTypedVariable

public void setTypedVariable(String name,
                             Class type,
                             Object value,
                             bsh.Modifiers modifiers)
            throws UtilEvalError
Declare a variable in the local scope and set its initial value. Value may be null to indicate that we would like the default value for the variable type. (e.g. 0 for integer types, null for object types). An existing typed variable may only be set to the same type. If an untyped variable of the same name exists it will be overridden with the new typed var. The set will perform a getAssignableForm() on the value if necessary.

Note: this method is primarily intended for use internally. If you use this method outside of the bsh package and wish to set variables with primitive values you will have to wrap them using bsh.Primitive.

Parameters:
value - If value is null, you'll get the default value for the type
modifiers - may be null
See Also:
Primitive

setVariable

public void setVariable(String name,
                        Object value,
                        boolean strictJava)
            throws UtilEvalError
Set the variable through this namespace. This method obeys the LOCALSCOPING property to determine how variables are set.

Note: this method is primarily intended for use internally. If you use this method outside of the bsh package and wish to set variables with primitive values you will have to wrap them using bsh.Primitive.

Parameters:
strictJava - specifies whether strict java rules are applied.

toString

public String toString()

unsetVariable

public void unsetVariable(String name)
Remove the variable from the namespace.

unwrapVariable

protected Object unwrapVariable(bsh.NameSpace.Variable var)
Unwrap a variable to its value.
Returns:
return the variable value. A null var is mapped to Primitive.VOID

B) 2000 pat@pat.net :-)