webwork.util

Class ValueStack

java.lang.Object

webwork.util.ValueStack

All Implemented Interfaces:

Iterable<Object>

Direct Known Subclasses:

ServletValueStack

public class ValueStack
extends Object
implements Iterable<Object>

Value stack. A VS is used by the WebWork system as a way to make findInContext values available by using the push and pop methods. They can then be accessed by using the find* methods.

Version:

$Revision: 1.61 $

Author:

Rickard Öberg (rickard@middleware-company.com), Maurice C. Parker (maurice@vineyardenterprise.com)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ValueStack.ValueHolder

Field Summary

Fields

Modifier and Type	Field and Description
protected static Map<Class<?>,Map<String,webwork.util.ValueStack.MethodInfo[]>>	classes
static String	STACK_NAME
static String	WEBWORK_VALUE_STACK_LOG_EXCEPTIONS A System property name that controls whether value stack exceptions are logged or not.

Constructor Summary

Constructors

Constructor and Description
ValueStack()

Method Summary

Methods

Modifier and Type	Method and Description
static void	clearMethods() Clear the method cache.
protected Object	findInContext(String id) Find a value by id.
protected webwork.util.ValueStack.MethodInfo	findMethod(webwork.util.ValueStack.MethodInfo[] m, Object[] params)
Object	findValue(Query q)
Object	findValue(String query) Find a value for a given name.
protected webwork.util.ValueStack.MethodInfo[]	getMethod(Class<?> cl, String name) Get a method with a given name.
protected Object	getParameter(String aName)
boolean	isEmpty() Returns TRUE is the value stack is empty.
Iterator<Object>	iterator()
Object	peek() Peek at the object that is at the top of the stack.
Object	popValue() Pop a value from the value stack.
void	pushValue(Object value) Push a value onto the value stack.
int	size() Returns the size of the value stack.
boolean	test(String expression) Resolve a WebWork expression statement.
String	toString() Return a string representation of the Stack
protected Object	unwrap(Object value)

Methods inherited from class java.lang.Object

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

Field Detail

STACK_NAME

public static final String STACK_NAME

See Also:

Constant Field Values

WEBWORK_VALUE_STACK_LOG_EXCEPTIONS

public static final String WEBWORK_VALUE_STACK_LOG_EXCEPTIONS

A System property name that controls whether value stack exceptions are logged or not. By default they are logged.

See Also:

Constant Field Values

classes

protected static final Map<Class<?>,Map<String,webwork.util.ValueStack.MethodInfo[]>> classes

Constructor Detail

ValueStack

public ValueStack()

Method Detail

clearMethods

public static void clearMethods()

Clear the method cache. This must be called if the application is restarted.

pushValue

public void pushValue(Object value)

Push a value onto the value stack.

Parameters:

value - the value

peek

public Object peek()

Peek at the object that is at the top of the stack. The object is returned unmodified, so if it would be a ValueHolder it is not unwrapped

popValue

public Object popValue()

Pop a value from the value stack.

Returns:

the popped value

iterator

public Iterator<Object> iterator()

Specified by:

iterator in interface Iterable<Object>

size

public int size()

Returns the size of the value stack.

Returns:

size of value stack

isEmpty

public boolean isEmpty()

Returns TRUE is the value stack is empty.

Returns:

true is value stack is empty

test

public boolean test(String expression)

Resolve a WebWork expression statement.

Parameters:

expression -

Returns:

the boolean result of the expression

findInContext

protected Object findInContext(String id)

Find a value by id. This method can be overridden by subclasses to have some context concept to evaluate

Parameters:

id - the value id.

Returns:

value

unwrap

protected Object unwrap(Object value)

findValue

public Object findValue(String query)
                 throws IllegalArgumentException

Find a value for a given name.

Parameters:

query -

Returns:

the object corresponding to the query

Throws:

IllegalArgumentException

findValue

public Object findValue(Query q)
                 throws IllegalArgumentException

Throws:

IllegalArgumentException

toString

public String toString()

Return a string representation of the Stack

Overrides:

toString in class Object

Returns:

the stack as a String

getMethod

protected webwork.util.ValueStack.MethodInfo[] getMethod(Class<?> cl,
                                             String name)
                                                  throws IntrospectionException

Get a method with a given name.

Parameters:

cl - the class of the method

name - the name of the method

Returns:

the wanted method

Throws:

IntrospectionException

findMethod

protected webwork.util.ValueStack.MethodInfo findMethod(webwork.util.ValueStack.MethodInfo[] m,
                                            Object[] params)

getParameter

protected Object getParameter(String aName)