Package org.zkoss.zk.scripting.bsh

Class BSHInterpreter

java.lang.Object

org.zkoss.zk.scripting.util.GenericInterpreter

org.zkoss.zk.scripting.bsh.BSHInterpreter

All Implemented Interfaces:

HierarchicalAware, Interpreter, SerializableAware

public class BSHInterpreter
extends GenericInterpreter
implements SerializableAware, HierarchicalAware

The interpreter that uses BeanShell to interpret zscript codes.

Unlike many other implementations, it supports the hierarchical scopes (HierarchicalAware). That is, it uses an independent BeanShell NameSpace (a.k.a. interpreter's scope) to store the variables/classes/methods defined in BeanShell script for each ZK scope (Scope). Since one-to-one relationship between BeanShell's scope and ZK scope, the invocation of BeanShell methods can execute correctly without knowing what scope it is. However, if you want your codes portable across different interpreters, you had better to call Scopes.beforeInterpret(org.zkoss.zk.ui.ext.Scope) to prepare the proper scope, before calling any method defined in zscript.

How serialization work?

First, all NameSpace objects have to serialize. Second, the top-level namespace (GlobalNS) is wrapped with NSWrap, which is not serializable. It is serialized when SerializableAware.write(java.io.ObjectOutputStream, org.zkoss.zk.scripting.SerializableAware.Filter) is called (triggered by PageImpl's write).

On the other hand, all non-top-level namespaces (NS) are wrapped with NSWrapSR which is serializable, so they are serialized with the attributes of a ID space owner being serialized.

Author:

tomyeh

Nested Class Summary

Nested classes/interfaces inherited from interface org.zkoss.zk.scripting.SerializableAware

SerializableAware.Filter

Field Summary

Fields inherited from class org.zkoss.zk.scripting.util.GenericInterpreter

UNDEFINED

Constructor Summary

Constructors

Constructor	Description
BSHInterpreter()

Method Summary

Modifier and Type	Method	Description
protected boolean	contains(String name)	Tests whether a variable is defined in this interpreter.
protected boolean	contains(Scope scope, String name)	Tests whether a variable is defined in the interpreter's scope associated with the specified scope.
void	destroy()	Reset the owner (GenericInterpreter.getOwner()) to null.
protected void	exec(String script)	Executes the specified script.
protected Object	get(String name)	Gets the variable from the interpreter.
protected Object	get(Scope scope, String name)	Gets the variable from the interpreter's scope associated with the giving scope.
Class<?>	getClass(String clsnm)	Returns null since retrieving class is not supported.
org.zkoss.xel.Function	getFunction(String name, Class[] argTypes)	Returns null since retrieving methods is not supported.
org.zkoss.xel.Function	getFunction(Scope scope, String name, Class[] argTypes)	Returns null since retrieving methods is not supported.
Object	getNativeInterpreter()	Returns the native interpreter, or null if it is not initialized or destroyed.
void	init(Page owner, String zslang)	Initializes the interpreter.
protected void	loadDefaultImports(bsh.NameSpace bshns)	Called when the top-level BeanShell scope is created.
void	read(ObjectInputStream s)	Reads the name and value of the variable from the specified input stream.
protected void	set(String name, Object val)	Sets the variable to the interpreter.
protected void	set(Scope scope, String name, Object val)	Sets the variable to the interpreter's scope associated with the giving scope.
protected void	unset(String name)	Removes the variable from the interpreter.
protected void	unset(Scope scope, String name)	Removes the variable from the interpreter.
void	write(ObjectOutputStream s, SerializableAware.Filter filter)	Writes the name and value of the variables of this namespace to the specified stream.

Methods inherited from class org.zkoss.zk.scripting.util.GenericInterpreter

afterExec, afterInterpret, beforeExec, beforeInterpret, containsVariable, containsVariable, getCurrent, getFromNamespace, getFromNamespace, getImplicit, getLanguage, getOwner, getVariable, getVariable, interpret, setVariable, setVariable, unsetVariable, unsetVariable

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.zkoss.zk.scripting.HierarchicalAware

containsVariable, getVariable, setVariable, unsetVariable

Constructor Details

BSHInterpreter

public BSHInterpreter()

Method Details

loadDefaultImports

protected void loadDefaultImports(bsh.NameSpace bshns)

Called when the top-level BeanShell scope is created. By default, it does nothing.

Note: to speed up the performance, this implementation disabled NameSpace.loadDefaultImports(). It only imports the java.lang and java.util packages. If you want the built command and import packages, you can override this method. For example,

protected void loadDefaultImports(NameSpace bshns) {
  bshns.importCommands("/bsh/commands");
}

Since:

3.0.2

exec

protected void exec(String script)

Description copied from class: GenericInterpreter

Executes the specified script. Deriving class shall provide an implementation of this method, rather than overriding GenericInterpreter.interpret(java.lang.String, org.zkoss.zk.ui.ext.Scope).

Specified by:

exec in class GenericInterpreter

contains

protected boolean contains(String name)

Description copied from class: GenericInterpreter

Tests whether a variable is defined in this interpreter. Optional. Implement it if the interpreter can tell the difference between null and undefined.

By default, it tests whether GenericInterpreter.get(String) returns non-null.

Overrides:

contains in class GenericInterpreter

contains

protected boolean contains(Scope scope,
 String name)

Description copied from class: GenericInterpreter

Tests whether a variable is defined in the interpreter's scope associated with the specified scope. Optional. Implement it if the interpreter can tell the difference between null and undefined.

By default, it tests whether GenericInterpreter.get(Scope, String) returns non-null.

Overrides:

contains in class GenericInterpreter

get

protected Object get(String name)

Description copied from class: GenericInterpreter

Gets the variable from the interpreter. Optional. Implement it if you want to expose variables defined in the interpreter to Java codes.

GenericInterpreter.beforeExec() is called first, before this method is invoked.

An empty (and fake) scope is pushed so GenericInterpreter.getFromNamespace(java.lang.String) always returns null.

Overrides:

get in class GenericInterpreter

get

protected Object get(Scope scope,
 String name)

Description copied from class: GenericInterpreter

Gets the variable from the interpreter's scope associated with the giving scope. Optional. Implement it if you want to expose variables defined in the interpreter to Java codes.

This method is implemented only if the interpreter that supports hierarchical scopes (HierarchicalAware).

Default: the same as GenericInterpreter.get(String).

GenericInterpreter.beforeExec() is called first, before this method is invoked.

An empty (and fake) scope is pushed so GenericInterpreter.getFromNamespace(java.lang.String) always returns null.

Overrides:

get in class GenericInterpreter

set

protected void set(String name,
 Object val)

Description copied from class: GenericInterpreter

Sets the variable to the interpreter. Optional. Implement it if you want to allow Java codes to define a variable in the interpreter.

GenericInterpreter.beforeExec() is called first, before this method is invoked.

Overrides:

set in class GenericInterpreter

set

protected void set(Scope scope,
 String name,
 Object val)

Description copied from class: GenericInterpreter

Sets the variable to the interpreter's scope associated with the giving scope. Optional. Implement it if you want to allow Java codes to define a variable in the interpreter.

This method is implemented only if the interpreter that supports hierarchical scopes (HierarchicalAware).

Default: the same as GenericInterpreter.set(String, Object).

GenericInterpreter.beforeExec() is called first, before this method is invoked.

Overrides:

set in class GenericInterpreter

unset

protected void unset(String name)

Description copied from class: GenericInterpreter

Removes the variable from the interpreter. Optional. Implement it if you want to allow Java codes to undefine a variable from the interpreter.

GenericInterpreter.beforeExec() is called first, before this method is invoked.

Overrides:

unset in class GenericInterpreter

unset

protected void unset(Scope scope,
 String name)

Description copied from class: GenericInterpreter

Removes the variable from the interpreter. Optional. Implement it if you want to allow Java codes to undefine a variable from the interpreter.

This method is implemented only if the interpreter that supports hierarchical scopes (HierarchicalAware).

Default: the same as GenericInterpreter.unset(String).

GenericInterpreter.beforeExec() is called first, before this method is invoked.

Overrides:

unset in class GenericInterpreter

init

public void init(Page owner,
 String zslang)

Description copied from interface: Interpreter

Initializes the interpreter. It is called once when the new instance of interpreter is constructed.

Specified by:

init in interface Interpreter

Overrides:

init in class GenericInterpreter

zslang - the language this interpreter is associated with

destroy

public void destroy()

Description copied from class: GenericInterpreter

Reset the owner (GenericInterpreter.getOwner()) to null.

Specified by:

destroy in interface Interpreter

Overrides:

destroy in class GenericInterpreter

getNativeInterpreter

public Object getNativeInterpreter()

Returns the native interpreter, or null if it is not initialized or destroyed. From application's standpoint, it never returns null, and the returned object must be an instance of Interpreter

Specified by:

getNativeInterpreter in interface Interpreter

Since:

3.0.2

getClass

public Class<?> getClass(String clsnm)

Description copied from class: GenericInterpreter

Returns null since retrieving class is not supported.

Specified by:

getClass in interface Interpreter

Overrides:

getClass in class GenericInterpreter

getFunction

public org.zkoss.xel.Function getFunction(String name,
 Class[] argTypes)

Description copied from class: GenericInterpreter

Returns null since retrieving methods is not supported.

Specified by:

getFunction in interface Interpreter

Overrides:

getFunction in class GenericInterpreter

argTypes - the list of argument (a.k.a., parameter) types. If null, Class[0] is assumed.

getFunction

public org.zkoss.xel.Function getFunction(Scope scope,
 String name,
 Class[] argTypes)

Description copied from class: GenericInterpreter

Returns null since retrieving methods is not supported.

Specified by:

getFunction in interface HierarchicalAware

Overrides:

getFunction in class GenericInterpreter

Parameters:

scope - the scope used as a reference to identify the correct scope for searching the method. Note: this method doesn't look for any variable stored in scope.

argTypes - the list of argument (a.k.a., parameter) types. If null, Class[0] is assumed.

write

public void write(ObjectOutputStream s,
 SerializableAware.Filter filter)
           throws IOException

Description copied from interface: SerializableAware

Writes the name and value of the variables of this namespace to the specified stream.

If the variable's value is not serializable, it won't be written.

To read back, use SerializableAware.read(java.io.ObjectInputStream).

Specified by:

write in interface SerializableAware

Throws:

IOException

read

public void read(ObjectInputStream s)
          throws IOException,
ClassNotFoundException

Description copied from interface: SerializableAware

Reads the name and value of the variable from the specified input stream.

Specified by:

read in interface SerializableAware

Throws:

IOException

ClassNotFoundException

See Also:

• SerializableAware.write(java.io.ObjectOutputStream, org.zkoss.zk.scripting.SerializableAware.Filter)