Validator (Java EE 5)

Validator 实现是可以对 javax.faces.component.EditableValueHolder 执行验证（正确性检查）的类。视图中的每个 javax.faces.component.EditableValueHolder 可以关联 0 个或多个 Validator，并在请求处理生命周期的处理验证 阶段调用这些验证器。

各个 Validator 应检查传递给它的值和组件，并抛出包含 javax.faces.application.FacesMessage 的 ValidatorException，同时记录任何不符合必要规则的失败情况。

为了实现最大的普遍性，应该可以根据 Validator 实现类的属性配置 Validator 实例。例如，范围检查 Validator 应支持配置要使用的最小值和最大值。

Validator 实现必须提供一个公共的无参构造方法。此外，如果 Validator 类希望与视图一同保存和恢复配置的属性值，则该实现还必须实现 StateHolder。

A Validator implementation is a class that can perform validation (correctness checks) on a EditableValueHolder. Zero or more Validators can be associated with each EditableValueHolder in the view, and are called during the Process Validations phase of the request processing lifecycle.

Individual Validators should examine the value and component that they are passed, and throw a ValidatorException containing a FacesMessage, documenting any failures to conform to the required rules.

For maximum generality, Validator instances may be configurable based on properties of the Validator implementation class. For example, a range check Validator might support configuration of the minimum and maximum values to be used.

Validator implementations must have a zero-arguments public constructor. In addition, if the Validator class wishes to have configuration property values saved and restored with the view, the implementation must also implement StateHolder.

英文文档：

NOT_IN_RANGE_MESSAGE_ID

static final String NOT_IN_RANGE_MESSAGE_ID

Deprecated. Use DoubleRangeValidator.NOT_IN_RANGE_MESSAGE_ID or LongRangeValidator.NOT_IN_RANGE_MESSAGE_ID instead.

The message identifier of the FacesMessage to be created if the maximum or minimum value check fails, and both the maximum and minimum values for this validator have been set. The message format string for this message may optionally include a {0} placeholder, which will be replaced by the configured minimum value, and a {1} placeholder, which will be replaced by the configured maximum value.

See Also:

Constant Field Values

public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException

根据指定的 UIComponent 执行此 Validator 实现的正确性检查。如果发现任何违规情况，将抛出包含描述该失败的 javax.faces.application.FacesMessage 的 ValidatorException。

context	要处理的请求的 FacesContext
component	要检查正确性的 UIComponent
value	要验证的值
Throws	ValidatorException: 如果验证失败
Throws	NullPointerException: 如果 context 或 component 为 null

英文文档：

validate

void validate(FacesContext context,
              UIComponent component,
              Object value)
              throws ValidatorException

Perform the correctness checks implemented by this Validator against the specified UIComponent. If any violations are found, a ValidatorException will be thrown containing the FacesMessage describing the failure.

Parameters:

context - FacesContext for the request we are processing

component - UIComponent we are checking for correctness

value - the value to validate

Throws:

ValidatorException - if validation fails

NullPointerException - if context or component is null

Copyright 2007 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.