org.apache.struts2.util

Interface ValueStack

All Known Subinterfaces:

ValueStack

All Known Implementing Classes:

OgnlValueStack, ValueStack.LegacyAdapter

public interface ValueStack

ValueStack allows multiple beans to be pushed in and dynamic EL expressions to be evaluated against it. When evaluating an expression, the stack will be searched down the stack, from the latest objects pushed in to the earliest, looking for a bean with a getter or setter for the given property or a method of the given name (depending on the expression being evaluated).

Field Summary

Fields

Modifier and Type	Field and Description
static String	REPORT_ERRORS_ON_NO_PROP
static String	VALUE_STACK

Method Summary

Modifier and Type	Method and Description
String	findString(String expr)
String	findString(String expr, boolean throwExceptionOnFailure)
Object	findValue(String expr) Find a value by evaluating the given expression against the stack in the default search order.
Object	findValue(String expr, boolean throwExceptionOnFailure)
Object	findValue(String expr, Class asType) Find a value by evaluating the given expression against the stack in the default search order.
Object	findValue(String expr, Class asType, boolean throwExceptionOnFailure)
ActionContext	getActionContext()
Map<String,Object>	getContext() Gets the context for this value stack.
Map<Object,Object>	getExprOverrides() Gets the override map if anyone exists.
CompoundRoot	getRoot() Get the CompoundRoot which holds the objects pushed onto the stack
Object	peek() Get the object on the top of the stack without changing the stack.
Object	pop() Get the object on the top of the stack and remove it from the stack.
void	push(Object o) Put this object onto the top of the stack
void	set(String key, Object o) Sets an object on the stack with the given key so it is retrievable by findValue(String), findValue(String, Class)
void	setDefaultType(Class defaultType) Sets the default type to convert to if no type is provided when getting a value.
void	setExprOverrides(Map<Object,Object> overrides) Set a override map containing key -> values that takes precedent when doing find operations on the ValueStack.
void	setParameter(String expr, Object value) Attempts to set a property on a bean in the stack with the given expression using the default search order.
void	setValue(String expr, Object value) Attempts to set a property on a bean in the stack with the given expression using the default search order.
void	setValue(String expr, Object value, boolean throwExceptionOnFailure) Attempts to set a property on a bean in the stack with the given expression using the default search order.
int	size() Get the number of objects in the stack

Field Detail

VALUE_STACK

static final String VALUE_STACK

See Also:

Constant Field Values

REPORT_ERRORS_ON_NO_PROP

static final String REPORT_ERRORS_ON_NO_PROP

See Also:

Constant Field Values

Method Detail

getContext

Map<String,Object> getContext()

Gets the context for this value stack. The context holds all the information in the value stack and it's surroundings.

Returns:

the context.

getActionContext

ActionContext getActionContext()

setDefaultType

void setDefaultType(Class defaultType)

Sets the default type to convert to if no type is provided when getting a value.

Parameters:

defaultType - the new default type

setExprOverrides

void setExprOverrides(Map<Object,Object> overrides)

Set a override map containing key -> values that takes precedent when doing find operations on the ValueStack.

See the unit test for ValueStackTest for examples.

Parameters:

overrides - overrides map.

getExprOverrides

Map<Object,Object> getExprOverrides()

Gets the override map if anyone exists.

Returns:

the override map, null if not set.

getRoot

CompoundRoot getRoot()

Get the CompoundRoot which holds the objects pushed onto the stack

Returns:

the root

setValue

void setValue(String expr,
              Object value)

Attempts to set a property on a bean in the stack with the given expression using the default search order.

Parameters:

expr - the expression defining the path to the property to be set.

value - the value to be set into the named property

setParameter

void setParameter(String expr,
                  Object value)

Attempts to set a property on a bean in the stack with the given expression using the default search order. N.B.: unlike #setValue(String,Object) it doesn't allow eval expression.

Parameters:

expr - the expression defining the path to the property to be set.

value - the value to be set into the named property

setValue

void setValue(String expr,
              Object value,
              boolean throwExceptionOnFailure)

Attempts to set a property on a bean in the stack with the given expression using the default search order.

Parameters:

expr - the expression defining the path to the property to be set.

value - the value to be set into the named property

throwExceptionOnFailure - a flag to tell whether an exception should be thrown if there is no property with the given name.

findString

String findString(String expr)

findString

String findString(String expr,
                  boolean throwExceptionOnFailure)

findValue

Object findValue(String expr)

Find a value by evaluating the given expression against the stack in the default search order.

Parameters:

expr - the expression giving the path of properties to navigate to find the property value to return

Returns:

the result of evaluating the expression

findValue

Object findValue(String expr,
                 boolean throwExceptionOnFailure)

findValue

Object findValue(String expr,
                 Class asType)

Find a value by evaluating the given expression against the stack in the default search order.

Parameters:

expr - the expression giving the path of properties to navigate to find the property value to return

asType - the type to convert the return value to

Returns:

the result of evaluating the expression

findValue

Object findValue(String expr,
                 Class asType,
                 boolean throwExceptionOnFailure)

peek

Object peek()

Get the object on the top of the stack without changing the stack.

Returns:

the object on the top.

See Also:

CompoundRoot.peek()

pop

Object pop()

Get the object on the top of the stack and remove it from the stack.

Returns:

the object on the top of the stack

See Also:

CompoundRoot.pop()

push

void push(Object o)

Put this object onto the top of the stack

Parameters:

o - the object to be pushed onto the stack

See Also:

CompoundRoot.push(Object)

set

void set(String key,
         Object o)

Sets an object on the stack with the given key so it is retrievable by findValue(String), findValue(String, Class)

Parameters:

key - the key

o - the object

size

int size()

Get the number of objects in the stack

Returns:

the number of objects in the stack