Package org.apache.tapestry5.internal

Class EmptyEventContext

java.lang.Object

org.apache.tapestry5.internal.EmptyEventContext

All Implemented Interfaces:

EventContext

public class EmptyEventContext
extends java.lang.Object
implements EventContext

Placeholder used when no context is available.

Constructor Summary

Constructors

Constructor	Description
EmptyEventContext()

Method Summary

Modifier and Type	Method	Description
<T> T	get(java.lang.Class<T> desiredType, int index)	This should never be called because the count is always zero.
int	getCount()	Always returns zero.
boolean	isEmpty()	Returns true if this context contains no elements.
java.lang.String[]	toStrings()	Extracts the value of each context value as a string.
<T> java.util.Optional<T>	tryGet(java.lang.Class<T> desiredType, int index)	Tries to extract a parameter value and coerces or decodes it to the desired type.

Methods inherited from class java.lang.Object

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

Constructor Detail

EmptyEventContext

public EmptyEventContext()

Method Detail

getCount

public int getCount()

Always returns zero.

Specified by:

getCount in interface EventContext

get

public <T> T get(java.lang.Class<T> desiredType,
                 int index)

This should never be called because the count is always zero.

Specified by:

get in interface EventContext

Parameters:

desiredType - the type of value required

index - identifies which parameter value to extract

Returns:

the value extracted and converted or coerced

toStrings

public java.lang.String[] toStrings()

Description copied from interface: EventContext

Extracts the value of each context value as a string.

Specified by:

toStrings in interface EventContext

Returns:

context values

isEmpty

public boolean isEmpty()

Description copied from interface: EventContext

Returns true if this context contains no elements.

Specified by:

isEmpty in interface EventContext

tryGet

public <T> java.util.Optional<T> tryGet(java.lang.Class<T> desiredType,
                                        int index)

Description copied from interface: EventContext

Tries to extract a parameter value and coerces or decodes it to the desired type.

Specified by:

tryGet in interface EventContext

Parameters:

desiredType - the type of value required

index - identifies which parameter value to extract

Returns:

the value extracted and converted or coerced, wrapped in an Optional, or Optional.empty() if index is out of bounds, or the value can't be converted.