How to use validate() in java

validate() method is used to verify the legality of components and sub-components. It is verified according to InputVerifier. The return value is a Boolean value, indicating whether it is valid: calculate the optimal size and re-layout. Iterate through the child components and call their validate() method. Call InputVerifier to verify the input: if validation fails, the mark is invalid and false is returned. If the verification is successful, the tag is valid and true is returned.

##Usage of validate() method in Java

validate() Method in In Java, it is a method defined in the Component class and all its subclasses. It is used to check the validity of a component and its subcomponents and validate them against the component's InputVerifier settings.

Usage

##validate()

The method is called as follows: <pre class="brush:php;toolbar:false">&lt;code class=&quot;java&quot;&gt;public boolean validate()&lt;/code&gt;</pre>

Return value

validate()

The method returns a Boolean value indicating whether the component and its subcomponents are all valid. Returns true if all components are valid; otherwise, returns false.

When to use

validate()

method is usually used in the following situations:

When the user submits form or perform other operations that may cause the component's state to change.

• When the internal state of the component itself changes.

Detailed Description

When the

validate()

method is called, it will perform the following steps:

Call the

revalidate()
1. method, which calculates the optimal size of the component and forces a relayout. For each subcomponent of the component, call its
validate()
2. method. Call the
getInputVerifier()
3. method to get the component's InputVerifier (if it exists). If
InputVerifier
4. exists, call its verify() method to verify the input of the component.
If validation fails (

InputVerifier

returns false), the component will be marked as invalid and the validate() method will Return false. Otherwise, the component will be marked as valid and the validate() method will return true.

Best Practice

Call

validate in the component's
• ActionEvent or FocusEvent handler () method to ensure validation when the user enters or changes focus. Create a custom
InputVerifier
• to verify a component's specific input. Use
setEnabled(false)
• to disable invalid components to prevent users from interacting with them.

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