BlankOption (Tapestry API - 5.7.2)乐学网一站式学习平台

java.lang.Object
- java.lang.Enum<BlankOption>
- - org.apache.tapestry5.corelib.data.BlankOption

All Implemented Interfaces:

Serializable, Comparable<BlankOption>
```
public enum BlankOption
extends Enum<BlankOption>
```
Used with the Select component to control whether an initial blank option is supplied. Determines the optionality of the undelrying property from the Select's validate parameter

Enum Constant Summary

Enum Constants
Enum Constant	Description
`ALWAYS`	Always include the blank option, even if the underlying property is required.
`AUTO`	The default: include the blank option if the underlying property is optional.
`NEVER`	Never include the blank option, even if the underlying property is optional.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static BlankOption`	`valueOf(String name)`	Returns the enum constant of this type with the specified name.
`static BlankOption[]`	`values()`	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Enum Constant Detail
  - ALWAYS
```
public static final BlankOption ALWAYS
```
    Always include the blank option, even if the underlying property is required.
  - NEVER
```
public static final BlankOption NEVER
```
    Never include the blank option, even if the underlying property is optional.
  - AUTO
```
public static final BlankOption AUTO
```
    The default: include the blank option if the underlying property is optional.
- Method Detail
  - values
```
public static BlankOption[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
    for (BlankOption c : BlankOption.values()) System.out.println(c);
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static BlankOption valueOf(String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    
    name - the name of the enum constant to be returned.
    
    Returns:
    
    the enum constant with the specified name
    
    Throws:
    
    IllegalArgumentException - if this enum type has no constant with the specified name
    
    NullPointerException - if the argument is null