bsh
Class NameSpace

java.lang.Object
  |
  +--bsh.NameSpace
All Implemented Interfaces:
BshClassManager.Listener, NameSource, java.io.Serializable

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

Nested Class Summary
 
Nested classes inherited from class bsh.NameSource
NameSource.Listener
 
Field Summary
 boolean isMethod
          Note that the namespace is a method body namespace.
static NameSpace JAVACODE
           
 java.lang.String nsName
           
 
Constructor Summary
NameSpace(BshClassManager classManager, java.lang.String name)
           
NameSpace(NameSpace parent, BshClassManager classManager, java.lang.String name)
           
NameSpace(NameSpace parent, java.lang.String name)
           
 
Method Summary
 void addNameSourceListener(NameSource.Listener listener)
          Implements NameSource Add a listener who is notified upon changes to names in this space.
 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.
 java.lang.Object get(java.lang.String name, Interpreter interpreter)
          Resolve name to an object through this namespace.
 java.lang.String[] getAllNames()
          Implements NameSource
protected  void getAllNamesAux(java.util.Vector vec)
          Helper for implementing NameSource
static java.lang.Object getAssignableForm(java.lang.Object rhs, java.lang.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.

 java.lang.Class getClass(java.lang.String name)
          Load a class through this namespace taking into account imports.
 BshClassManager getClassManager()
           
 java.lang.Object getCommand(java.lang.String name, java.lang.Class[] argTypes, Interpreter interpreter)
          A command is a scripted method or compiled command class implementing a specified method signature.
 NameSpace getGlobal()
           
 int getInvocationLine()
           
 java.lang.String getInvocationText()
           
 BshMethod getMethod(java.lang.String name, java.lang.Class[] sig)
          Get the bsh method matching the specified signature declared in this name space or a parent.
 java.lang.String[] getMethodNames()
          Get the names of methods defined in this namespace.
 BshMethod[] getMethods()
          Get the methods defined in this namespace.
 java.lang.String getName()
           
 NameSpace getParent()
          Get the parent namespace.
 NameSpace getSuper()
           
 java.lang.Object getVariable(java.lang.String name)
          Get the specified variable in this namespace or a parent namespace.
 java.lang.Object getVariable(java.lang.String name, boolean recurse)
          Get the specified variable in this namespace.
protected  bsh.NameSpace.Variable getVariableImpl(java.lang.String name, boolean recurse)
          Locate a variable and return the Variable object with optional recursion through parent name spaces.
 java.lang.String[] getVariableNames()
          Get the names of variables defined in this namespace.
static java.lang.Class identifierToClass(ClassIdentifier ci)
          This is a helper method for working inside of bsh scripts and commands.
 void importClass(java.lang.String name)
          Import a class name.
 void importCommands(java.lang.String name)
          Import scripted or compiled BeanShell commands in the following package in the classpath.
 void importPackage(java.lang.String name)
          subsequent imports override earlier ones
 java.lang.Object invokeMethod(java.lang.String methodName, java.lang.Object[] args, Interpreter interpreter)
          Invoke a method in this namespace with the specified args and interpreter reference.
 java.lang.Object invokeMethod(java.lang.String methodName, java.lang.Object[] args, Interpreter interpreter, CallStack callstack, bsh.SimpleNode callerInfo)
          This method simply delegates to This.invokeMethod();
 void loadDefaultImports()
          Import standard packages.
 void nameSpaceChanged()
          Clear all cached classes and names
 void prune()
          Used for serialization
 void setMethod(java.lang.String name, BshMethod method)
          Note: this is primarily for internal use.
 void setName(java.lang.String name)
           
 void setParent(NameSpace parent)
           
 void setTypedVariable(java.lang.String name, java.lang.Class type, java.lang.Object value, boolean isFinal)
          Declare a variable in the local scope and set its initial value.
 void setVariable(java.lang.String name, java.lang.Object value, boolean strictJava)
          Set the variable through this namespace.
 java.lang.String toString()
           
 void unsetVariable(java.lang.String name)
          Remove the variable from the namespace.
protected  java.lang.Object unwrapVariable(bsh.NameSpace.Variable var)
          Unwrap a variable to its value.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

JAVACODE

public static final NameSpace JAVACODE

nsName

public java.lang.String nsName

isMethod

public boolean isMethod
Note that the namespace is a method body namespace. This is used for printing stack traces in exceptions.

Constructor Detail

NameSpace

public NameSpace(NameSpace parent,
                 java.lang.String name)

NameSpace

public NameSpace(BshClassManager classManager,
                 java.lang.String name)

NameSpace

public NameSpace(NameSpace parent,
                 BshClassManager classManager,
                 java.lang.String name)
Method Detail

setName

public void setName(java.lang.String name)

getName

public java.lang.String getName()

get

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

UtilEvalError

setVariable

public void setVariable(java.lang.String name,
                        java.lang.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.
UtilEvalError
See Also:

Setting a new variable (which didn't exist before) or removing a variable causes a namespace change.


unsetVariable

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


getVariableNames

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


getMethodNames

public java.lang.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).


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()

getGlobal

public NameSpace getGlobal()

getClassManager

public BshClassManager getClassManager()

prune

public void prune()
Used for serialization


setParent

public void setParent(NameSpace parent)

getVariable

public java.lang.Object getVariable(java.lang.String name)
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.
See Also:
Primitive.unwrap( Object )

getVariable

public java.lang.Object getVariable(java.lang.String name,
                                    boolean recurse)
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.
See Also:
Primitive.unwrap( Object )

getVariableImpl

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

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

unwrapVariable

protected java.lang.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

setTypedVariable

public void setTypedVariable(java.lang.String name,
                             java.lang.Class type,
                             java.lang.Object value,
                             boolean isFinal)
                      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
UtilEvalError
See Also:
Primitive

setMethod

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

See Also:
Interpreter.source( String ), Interpreter.eval( String )

getMethod

public BshMethod getMethod(java.lang.String name,
                           java.lang.Class[] sig)
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

importClass

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


importPackage

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


importCommands

public void importCommands(java.lang.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 "/".


getCommand

public java.lang.Object getCommand(java.lang.String name,
                                   java.lang.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

getClass

public java.lang.Class getClass(java.lang.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.
UtilEvalError

getAllNames

public java.lang.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(java.util.Vector vec)
Helper for implementing NameSource


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

doSuperImport

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

UtilEvalError

getAssignableForm

public static java.lang.Object getAssignableForm(java.lang.Object rhs,
                                                 java.lang.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:
lhsType - lhsType is a real Java class type or Java primitive TYPE
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.
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 )

toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object

invokeMethod

public java.lang.Object invokeMethod(java.lang.String methodName,
                                     java.lang.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.

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

invokeMethod

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

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

classLoaderChanged

public void classLoaderChanged()
Clear all cached classes and names

Specified by:
classLoaderChanged in interface BshClassManager.Listener

nameSpaceChanged

public void nameSpaceChanged()
Clear all cached classes and names


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");
                


getInvocationLine

public int getInvocationLine()

getInvocationText

public java.lang.String getInvocationText()

identifierToClass

public static java.lang.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 );


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.

See Also:
loadDefaultImports()


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