# Class Validator

java.lang.Object
org.apache.commons.validator.Validator

All Implemented Interfaces:
  `Serializable`

public class Validator extends Object implements Serializable
Validations are processed by the validate method. An instance of `ValidatorResources` is used to define the validators (validation methods) and the validation rules for a JavaBean.

See Also:
  - Serialized Form

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final String`
  `BEAN_PARAM`
  Resources key the JavaBean is stored to perform validation on.
  `protected ClassLoader`
  `classLoader`
  Deprecated.
  Use `getClassLoader()`, will be private in the next major version.
  `static final String`
  `FIELD_PARAM`
  Resources key the `Field` is stored under.
  `protected String`
  `fieldName`
  Deprecated.
  Use `getFieldName()`, will be private in the next major version.
  `static final String`
  `FORM_PARAM`
  Resources key the `Form` is stored under.
  `protected String`
  `formName`
  Deprecated.
  Use `getFormName()`, will be private in the next major version.
  `static final String`
  `LOCALE_PARAM`
  Resources key the `Locale` is stored.
  `protected boolean`
  `onlyReturnErrors`
  Deprecated.
  Use `getOnlyReturnErrors()`, will be private in the next major version.
  `protected int`
  `page`
  Deprecated.
  Use `getPage()`, will be private in the next major version.
  `protected Map<String,Object>`
  `parameters`
  Deprecated.
  Use `getParameters()`, will be private in the next major version.
  `protected ValidatorResources`
  `resources`
  Deprecated.
  Use `getResources()`, will be private in the next major version.
  `protected boolean`
  `useContextClassLoader`
  Deprecated.
  Use `getUseContextClassLoader()`, will be private in the next major version.
  `static final String`
  `VALIDATOR_ACTION_PARAM`
  Resources key the `ValidatorAction` is stored under.
  `static final String`
  `VALIDATOR_PARAM`
  Resources key the `Validator` is stored under.
  `static final String`
  `VALIDATOR_RESULTS_PARAM`
  Resources key the `ValidatorResults` is stored under.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Validator(ValidatorResources resources)`
  Constructs a `Validator` that will use the `ValidatorResources` passed in to retrieve pluggable validators the different sets of validation rules.
  `Validator(ValidatorResources resources, String formName)`
  Constructs a `Validator` that will use the `ValidatorResources` passed in to retrieve pluggable validators the different sets of validation rules.
  `Validator(ValidatorResources resources, String formName, String fieldName)`
  Constructs a `Validator` that will use the `ValidatorResources` passed in to retrieve pluggable validators the different sets of validation rules.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `clear()`
  Clears the form name, resources that were added, and the page that was set (if any).
  `ClassLoader`
  `getClassLoader()`
  Gets the class loader to be used for instantiating application objects when required.
  `String`
  `getFieldName()`
  Gets the field name.
  `String`
  `getFormName()`
  Gets the form name which is the key to a set of validation rules.
  `boolean`
  `getOnlyReturnErrors()`
  Returns true if the Validator is only returning Fields that fail validation.
  `int`
  `getPage()`
  Gets the page.
  `Map<String,Object>`
  `getParameters()`
  Gets the parameter map.
  `Object`
  `getParameterValue(String parameterClassName)`
  Returns the value of the specified parameter that will be used during the processing of validations.
  `ValidatorResources`
  `getResources()`
  Gets the validator resource.
  `boolean`
  `getUseContextClassLoader()`
  Gets the boolean as to whether the context classloader should be used.
  `void`
  `setClassLoader(ClassLoader classLoader)`
  Sets the class loader to be used for instantiating application objects when required.
  `void`
  `setFieldName(String fieldName)`
  Sets the name of the field to validate in a form (optional)
  `void`
  `setFormName(String formName)`
  Sets the form name which is the key to a set of validation rules.
  `void`
  `setOnlyReturnErrors(boolean onlyReturnErrors)`
  Configures which Fields the Validator returns from the validate() method.
  `void`
  `setPage(int page)`
  Sets the page.
  `void`
  `setParameter(String parameterClassName, Object parameterValue)`
  Sets a parameter of a pluggable validation method.
  `void`
  `setUseContextClassLoader(boolean useContextClassLoader)`
  Sets whether to use the Context ClassLoader (the one found by calling `Thread.currentThread().getContextClassLoader()`) to resolve/load classes that are defined in various rules.
  `ValidatorResults`
  `validate()`
  Performs validations based on the configured resources.

  ### Methods inherited from class Object

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

- ## Field Details

  - ### BEAN_PARAM

    public static final String BEAN_PARAM
    Resources key the JavaBean is stored to perform validation on.
    See Also:
      - Constant Field Values

  - ### FIELD_PARAM

    public static final String FIELD_PARAM
    Resources key the `Field` is stored under. This will be automatically passed into a validation method with the current `Field` if it is specified in the method signature.
    See Also:
      - Constant Field Values

  - ### FORM_PARAM

    public static final String FORM_PARAM
    Resources key the `Form` is stored under. This will be automatically passed into a validation method with the current `Form` if it is specified in the method signature.
    See Also:
      - Constant Field Values

  - ### LOCALE_PARAM

    public static final String LOCALE_PARAM
    Resources key the `Locale` is stored. This will be used to retrieve the appropriate `FormSet` and `Form` to be processed.
    See Also:
      - Constant Field Values

  - ### VALIDATOR_ACTION_PARAM

    public static final String VALIDATOR_ACTION_PARAM
    Resources key the `ValidatorAction` is stored under. This will be automatically passed into a validation method with the current `ValidatorAction` if it is specified in the method signature.
    See Also:
      - Constant Field Values

  - ### VALIDATOR_PARAM

    public static final String VALIDATOR_PARAM
    Resources key the `Validator` is stored under. This will be automatically passed into a validation method with the current `Validator` if it is specified in the method signature.
    See Also:
      - Constant Field Values

  - ### VALIDATOR_RESULTS_PARAM

    public static final String VALIDATOR_RESULTS_PARAM
    Resources key the `ValidatorResults` is stored under. This will be automatically passed into a validation method with the current `ValidatorResults` if it is specified in the method signature.
    See Also:
      - Constant Field Values

  - ### classLoader

    @Deprecated protected transient ClassLoader classLoader
    Deprecated.
    Use `getClassLoader()`, will be private in the next major version.
    The class loader to use for instantiating application objects. If not specified, the context class loader, or the class loader used to load Digester itself, is used, based on the value of the `useContextClassLoader` variable.

  - ### fieldName

    @Deprecated protected String fieldName
    Deprecated.
    Use `getFieldName()`, will be private in the next major version.
    The name of the field on the form to validate
    Since:
      1.2.0

  - ### formName

    @Deprecated protected String formName
    Deprecated.
    Use `getFormName()`, will be private in the next major version.
    The name of the form to validate

  - ### onlyReturnErrors

    @Deprecated protected boolean onlyReturnErrors
    Deprecated.
    Use `getOnlyReturnErrors()`, will be private in the next major version.
    Sets this to true to not return Fields that pass validation. Only return failures.

  - ### page

    @Deprecated protected int page
    Deprecated.
    Use `getPage()`, will be private in the next major version.
    The current page number to validate.

  - ### parameters

    @Deprecated protected Map<String,Object> parameters
    Deprecated.
    Use `getParameters()`, will be private in the next major version.
    Maps validation method parameter class names to the objects to be passed into the method.

  - ### resources

    @Deprecated protected ValidatorResources resources
    Deprecated.
    Use `getResources()`, will be private in the next major version.
    The Validator Resources.

  - ### useContextClassLoader

    @Deprecated protected boolean useContextClassLoader
    Deprecated.
    Use `getUseContextClassLoader()`, will be private in the next major version.
    Whether or not to use the Context ClassLoader when loading classes for instantiating new objects. Default is `false`.

- ## Constructor Details

  - ### Validator

    public Validator(ValidatorResources resources)
    Constructs a `Validator` that will use the `ValidatorResources` passed in to retrieve pluggable validators the different sets of validation rules.
    Parameters:
      `resources` - `ValidatorResources` to use during validation.

  - ### Validator

    public Validator(ValidatorResources resources, String formName)
    Constructs a `Validator` that will use the `ValidatorResources` passed in to retrieve pluggable validators the different sets of validation rules.
    Parameters:
      `resources` - `ValidatorResources` to use during validation.
      `formName` - Key used for retrieving the set of validation rules.

  - ### Validator

    public Validator(ValidatorResources resources, String formName, String fieldName)
    Constructs a `Validator` that will use the `ValidatorResources` passed in to retrieve pluggable validators the different sets of validation rules.
    Parameters:
      `resources` - `ValidatorResources` to use during validation.
      `formName` - Key used for retrieving the set of validation rules.
      `fieldName` - Key used for retrieving the set of validation rules for a field
    Since:
      1.2.0

- ## Method Details

  - ### clear

    public void clear()
    Clears the form name, resources that were added, and the page that was set (if any). This can be called to reinitialize the Validator instance so it can be reused. The form name (key to set of validation rules) and any resources needed, like the JavaBean being validated, will need to set and/or added to this instance again. The `ValidatorResources` will not be removed since it can be used again and is thread safe.

  - ### getClassLoader

    public ClassLoader getClassLoader()
    Gets the class loader to be used for instantiating application objects when required. This is determined based upon the following rules:
    - The class loader set by `setClassLoader()`, if any
    - The thread context class loader, if it exists and the `useContextClassLoader` property is set to true
    - The class loader used to load the Digester class itself.
    Returns:
      The class loader.

  - ### getFieldName

    public String getFieldName()
    Gets the field name.
    Returns:
      The field name.
    Since:
      1.10.0

  - ### getFormName

    public String getFormName()
    Gets the form name which is the key to a set of validation rules.
    Returns:
      The name of the form.

  - ### getOnlyReturnErrors

    public boolean getOnlyReturnErrors()
    Returns true if the Validator is only returning Fields that fail validation.
    Returns:
      whether only failed fields are returned.

  - ### getPage

    public int getPage()
    Gets the page.

    This in conjunction with the page property of a `Field` can control the processing of fields. If the field's page is less than or equal to this page value, it will be processed.

    Returns:
      The page number.

  - ### getParameters

    public Map<String,Object> getParameters()
    Gets the parameter map.
    Returns:
      The parameter map.
    Since:
      1.10.0

  - ### getParameterValue

    public Object getParameterValue(String parameterClassName)
    Returns the value of the specified parameter that will be used during the processing of validations.
    Parameters:
      `parameterClassName` - The full class name of the parameter of the validation method that corresponds to the value/instance passed in with it.
    Returns:
      value of the specified parameter.

  - ### getResources

    public ValidatorResources getResources()
    Gets the validator resource.
    Returns:
      The validator resource.
    Since:
      1.10.0

  - ### getUseContextClassLoader

    public boolean getUseContextClassLoader()
    Gets the boolean as to whether the context classloader should be used.
    Returns:
      whether the context classloader should be used.

  - ### setClassLoader

    public void setClassLoader(ClassLoader classLoader)
    Sets the class loader to be used for instantiating application objects when required.
    Parameters:
      `classLoader` - The new class loader to use, or `null` to revert to the standard rules

  - ### setFieldName

    public void setFieldName(String fieldName)
    Sets the name of the field to validate in a form (optional)
    Parameters:
      `fieldName` - The name of the field in a form set
    Since:
      1.2.0

  - ### setFormName

    public void setFormName(String formName)
    Sets the form name which is the key to a set of validation rules.
    Parameters:
      `formName` - The name of the form.

  - ### setOnlyReturnErrors

    public void setOnlyReturnErrors(boolean onlyReturnErrors)
    Configures which Fields the Validator returns from the validate() method. Set this to true to only return Fields that failed validation. By default, validate() returns all fields.
    Parameters:
      `onlyReturnErrors` - whether only failed fields are returned.

  - ### setPage

    public void setPage(int page)
    Sets the page.

    This in conjunction with the page property of a `Field` can control the processing of fields. If the field's page is less than or equal to this page value, it will be processed.

    Parameters:
      `page` - The page number.

  - ### setParameter

    public void setParameter(String parameterClassName, Object parameterValue)
    Sets a parameter of a pluggable validation method.
    Parameters:
      `parameterClassName` - The full class name of the parameter of the validation method that corresponds to the value/instance passed in with it.
      `parameterValue` - The instance that will be passed into the validation method.

  - ### setUseContextClassLoader

    public void setUseContextClassLoader(boolean useContextClassLoader)
    Sets whether to use the Context ClassLoader (the one found by calling `Thread.currentThread().getContextClassLoader()`) to resolve/load classes that are defined in various rules. If not using Context ClassLoader, then the class-loading defaults to using the calling-class' ClassLoader.
    Parameters:
      `useContextClassLoader` - determines whether to use Context ClassLoader.

  - ### validate

    public ValidatorResults validate() throws ValidatorException
    Performs validations based on the configured resources.
    Returns:
      The `Map` returned uses the property of the `Field` for the key and the value is the number of error the field had.
    Throws:
      `ValidatorException` - If an error occurs during validation