## org.springframework.web.portlet.mvc
Class BaseCommandController

    java.lang.Object
      org.springframework.context.support.ApplicationObjectSupport
          org.springframework.web.portlet.context.PortletApplicationObjectSupport
              org.springframework.web.portlet.handler.PortletContentGenerator
                  org.springframework.web.portlet.mvc.AbstractController
                      org.springframework.web.portlet.mvc.BaseCommandController

All Implemented Interfaces:
  ApplicationContextAware, PortletContextAware, Controller

Direct Known Subclasses:
  AbstractCommandController, AbstractFormController

    public abstract class BaseCommandController

extends AbstractController

Controller implementation which creates an object (the command object) on receipt of a request and attempts to populate this object with request parameters.

This controller is the base for all controllers wishing to populate JavaBeans based on request parameters, validate the content of such JavaBeans using `Validators` and use custom editors (in the form of `PropertyEditors`) to transform objects into strings and vice versa, for example. Three notions are mentioned here:

Command class:
An instance of the command class will be created for each request and populated with request parameters. A command class can basically be any Java class; the only requirement is a no-arg constructor. The command class should preferably be a JavaBean in order to be able to populate bean properties with request parameters.

Populating using request parameters and PropertyEditors:
Upon receiving a request, any BaseCommandController will attempt to fill the command object using the request parameters. This is done using the typical and well-known JavaBeans property notation. When a request parameter named `'firstName'` exists, the framework will attempt to call `setFirstName([value])` passing the value of the parameter. Nested properties are of course supported. For instance a parameter named `'address.city'` will result in a `getAddress().setCity([value])` call on the command class.

It's important to realize that you are not limited to String arguments in your JavaBeans. Using the PropertyEditor-notion as supplied by the java.beans package, you will be able to transform Strings to Objects and the other way around. For instance `setLocale(Locale loc)` is perfectly possible for a request parameter named `locale` having a value of `en`, as long as you register the appropriate PropertyEditor in the Controller (see `initBinder()` for more information on that matter).

Validators: After the controller has successfully populated the command object with parameters from the request, it will use any configured validators to validate the object. Validation results will be put in a `Errors` object which can be used in a View to render any input problems.

Workflow (and that defined by superclass):
Since this class is an abstract base class for more specific implementation, it does not override the `handleRequestInternal()` methods and also has no actual workflow. Implementing classes like `AbstractFormController`, `AbstractCommandController`, `SimpleFormController` and `AbstractWizardFormController` provide actual functionality and workflow. More information on workflow performed by superclasses can be found here.

Exposed configuration properties (and those defined by superclass):

name | default | description
commandName | command | the name to use when binding the instantiated command class to the request
commandClass | null | the class to use upon receiving a request and which to fill using the request parameters. What object is used and whether or not it should be created is defined by extending classes and their configuration properties and methods.
validators | null | Array of Validator beans. The validator will be called at appropriate places in the workflow of subclasses (have a look at those for more info) to validate the command object.
validator | null | Short-form property for setting only one Validator bean (usually passed in using a <ref bean="beanId"/> property.
validateOnBinding | true | Indicates whether or not to validate the command object after the object has been populated with request parameters.

Thanks to Rainer Schmitz and Nick Lothian for their suggestions!

Since:
  2.0
Author:
  Juergen Hoeller, John A. Lewis

Field Summary
`static String` `DEFAULT_COMMAND_NAME`

Fields inherited from class org.springframework.context.support.ApplicationObjectSupport
`logger`

Constructor Summary
`BaseCommandController()`

Method Summary
`protected PortletRequestDataBinder` `bindAndValidate(javax.portlet.PortletRequest request, Object command)` Bind the parameters of the given request to the given command object.
`protected boolean` `checkCommand(Object command)` Check if the given command object is a valid for this controller, i.e. its command class.
`protected PortletRequestDataBinder` `createBinder(javax.portlet.PortletRequest request, Object command)` Create a new binder instance for the given command and request.
`protected Object` `createCommand()` Create a new command instance for the command class of this controller.
`BindingErrorProcessor` `getBindingErrorProcessor()` Return the strategy to use for processing binding errors (if any).
`protected Object` `getCommand(javax.portlet.PortletRequest request)` Retrieve a command object for the given request.
`Class` `getCommandClass()` Return the command class for this controller.
`String` `getCommandName()` Return the name of the command in the model.
`MessageCodesResolver` `getMessageCodesResolver()` Return the strategy to use for resolving errors into message codes (if any).
`PropertyEditorRegistrar[]` `getPropertyEditorRegistrars()` Return the PropertyEditorRegistrars (if any) to be applied to every DataBinder that this controller uses.
`protected Object` `getRenderCommand(javax.portlet.RenderRequest request)` Get the command object cached for the render phase.
`protected String` `getRenderCommandSessionAttributeName()` Return the name of the session attribute that holds the render phase command object for this form controller.
`protected BindException` `getRenderErrors(javax.portlet.RenderRequest request)` Get the bind and validation errors cached for the render phase.
`protected String` `getRenderErrorsSessionAttributeName()` Return the name of the session attribute that holds the render phase command object for this form controller.
`Validator` `getValidator()`
`Validator[]` `getValidators()` Return the Validators for this controller.
`WebBindingInitializer` `getWebBindingInitializer()` Return the WebBindingInitializer (if any) which will apply pre-configured configuration to every DataBinder that this controller uses.
`protected void` `initApplicationContext()` Subclasses can override this for custom initialization behavior.
`protected void` `initBinder(javax.portlet.PortletRequest request, PortletRequestDataBinder binder)` Initialize the given binder instance, for example with custom editors.
`boolean` `isValidateOnBinding()` Return if the Validator should get applied when binding.
`protected void` `onBind(javax.portlet.PortletRequest request, Object command)` Callback for custom post-processing in terms of binding.
`protected void` `onBind(javax.portlet.PortletRequest request, Object command, BindException errors)` Callback for custom post-processing in terms of binding.
`protected void` `onBindAndValidate(javax.portlet.PortletRequest request, Object command, BindException errors)` Callback for custom post-processing in terms of binding and validation.
`protected void` `prepareBinder(PortletRequestDataBinder binder)` Prepare the given binder, applying the specified MessageCodesResolver, BindingErrorProcessor and PropertyEditorRegistrars (if any).
`void` `setBindingErrorProcessor(BindingErrorProcessor bindingErrorProcessor)` Set the strategy to use for processing binding errors, that is, required field errors and `PropertyAccessException`s.
`void` `setCommandClass(Class commandClass)` Set the command class for this controller.
`void` `setCommandName(String commandName)` Set the name of the command in the model.
`void` `setMessageCodesResolver(MessageCodesResolver messageCodesResolver)` Set the strategy to use for resolving errors into message codes.
`void` `setPropertyEditorRegistrar(PropertyEditorRegistrar propertyEditorRegistrar)` Specify a single PropertyEditorRegistrar to be applied to every DataBinder that this controller uses.
`void` `setPropertyEditorRegistrars(PropertyEditorRegistrar[] propertyEditorRegistrars)` Specify one or more PropertyEditorRegistrars to be applied to every DataBinder that this controller uses.
`protected void` `setRenderCommandAndErrors(javax.portlet.ActionRequest request, Object command, BindException errors)` Set the command object and errors object for the render phase.
`void` `setValidateOnBinding(boolean validateOnBinding)` Set if the Validator should get applied when binding.
`void` `setValidator(Validator validator)` Set the primary Validator for this controller.
`void` `setValidators(Validator[] validators)` Set the Validators for this controller.
`void` `setWebBindingInitializer(WebBindingInitializer webBindingInitializer)` Specify a WebBindingInitializer which will apply pre-configured configuration to every DataBinder that this controller uses.
`protected boolean` `suppressBinding(javax.portlet.PortletRequest request)` Return whether to suppress binding for the given request.
`protected boolean` `suppressValidation(javax.portlet.PortletRequest request)` Return whether to suppress validation for the given request.
`protected boolean` `useDirectFieldAccess()` Determine whether to use direct field access instead of bean property access.

Methods inherited from class org.springframework.web.portlet.mvc.AbstractController
`handleActionRequest, handleActionRequestInternal, handleRenderRequest, handleRenderRequestInternal, isRenderWhenMinimized, isSynchronizeOnSession, setRenderWhenMinimized, setSynchronizeOnSession`

Methods inherited from class org.springframework.web.portlet.handler.PortletContentGenerator
`applyCacheSeconds, cacheForSeconds, check, checkAndPrepare, checkAndPrepare, getCacheSeconds, isRequireSession, preventCaching, setCacheSeconds, setRequireSession`

Methods inherited from class org.springframework.web.portlet.context.PortletApplicationObjectSupport
`getPortletContext, getTempDir, isContextRequired, setPortletContext`

Methods inherited from class org.springframework.context.support.ApplicationObjectSupport
`getApplicationContext, getMessageSourceAccessor, initApplicationContext, requiredContextClass, setApplicationContext`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### DEFAULT_COMMAND_NAME

    public static final String DEFAULT_COMMAND_NAME

See Also:
  Constant Field Values

Constructor Detail

### BaseCommandController

    public BaseCommandController()

Method Detail

### setCommandName

    public final void setCommandName(String commandName)

  Set the name of the command in the model. The command object will be included in the model under this name.

### getCommandName

    public final String getCommandName()

  Return the name of the command in the model.

### setCommandClass

    public final void setCommandClass(Class commandClass)

  Set the command class for this controller. An instance of this class gets populated and validated on each request.

### getCommandClass

    public final Class getCommandClass()

  Return the command class for this controller.

### setValidator

    public final void setValidator(Validator validator)

  Set the primary Validator for this controller. The Validator must support the specified command class. If there are one or more existing validators set already when this method is called, only the specified validator will be kept. Use `setValidators(Validator[])` to set multiple validators.

### getValidator

    public final Validator getValidator()

  Returns:
    the primary Validator for this controller.

### setValidators

    public final void setValidators(Validator[] validators)

  Set the Validators for this controller. The Validator must support the specified command class.

### getValidators

    public final Validator[] getValidators()

  Return the Validators for this controller.

### setValidateOnBinding

    public final void setValidateOnBinding(boolean validateOnBinding)

  Set if the Validator should get applied when binding.

### isValidateOnBinding

    public final boolean isValidateOnBinding()

  Return if the Validator should get applied when binding.

### setMessageCodesResolver

    public final void setMessageCodesResolver(MessageCodesResolver messageCodesResolver)

  Set the strategy to use for resolving errors into message codes. Applies the given strategy to all data binders used by this controller.

  Default is `null`, i.e. using the default strategy of the data binder.

  See Also:
    `createBinder(javax.portlet.PortletRequest, java.lang.Object)`, `DataBinder.setMessageCodesResolver(org.springframework.validation.MessageCodesResolver)`

### getMessageCodesResolver

    public final MessageCodesResolver getMessageCodesResolver()

  Return the strategy to use for resolving errors into message codes (if any).

### setBindingErrorProcessor

    public final void setBindingErrorProcessor(BindingErrorProcessor bindingErrorProcessor)

  Set the strategy to use for processing binding errors, that is, required field errors and `PropertyAccessException`s.

  Default is `null`, i.e. using the default strategy of the data binder.

  See Also:
    `createBinder(javax.portlet.PortletRequest, java.lang.Object)`, `DataBinder.setBindingErrorProcessor(org.springframework.validation.BindingErrorProcessor)`

### getBindingErrorProcessor

    public final BindingErrorProcessor getBindingErrorProcessor()

  Return the strategy to use for processing binding errors (if any).

### setPropertyEditorRegistrar

    public final void setPropertyEditorRegistrar(PropertyEditorRegistrar propertyEditorRegistrar)

  Specify a single PropertyEditorRegistrar to be applied to every DataBinder that this controller uses.

  Allows for factoring out the registration of PropertyEditors to separate objects, as an alternative to `initBinder`.

  See Also:
    `initBinder(javax.portlet.PortletRequest, org.springframework.web.portlet.bind.PortletRequestDataBinder)`

### setPropertyEditorRegistrars

    public final void setPropertyEditorRegistrars(PropertyEditorRegistrar[] propertyEditorRegistrars)

  Specify one or more PropertyEditorRegistrars to be applied to every DataBinder that this controller uses.

  Allows for factoring out the registration of PropertyEditors to separate objects, as alternative to `initBinder`.

  See Also:
    `initBinder(javax.portlet.PortletRequest, org.springframework.web.portlet.bind.PortletRequestDataBinder)`

### getPropertyEditorRegistrars

    public final PropertyEditorRegistrar[] getPropertyEditorRegistrars()

  Return the PropertyEditorRegistrars (if any) to be applied to every DataBinder that this controller uses.

### setWebBindingInitializer

    public final void setWebBindingInitializer(WebBindingInitializer webBindingInitializer)

  Specify a WebBindingInitializer which will apply pre-configured configuration to every DataBinder that this controller uses.

  Allows for factoring out the entire binder configuration to separate objects, as an alternative to `initBinder(javax.portlet.PortletRequest, org.springframework.web.portlet.bind.PortletRequestDataBinder)`.

### getWebBindingInitializer

    public final WebBindingInitializer getWebBindingInitializer()

  Return the WebBindingInitializer (if any) which will apply pre-configured configuration to every DataBinder that this controller uses.

### initApplicationContext

    protected void initApplicationContext()

  Description copied from class: `ApplicationObjectSupport`
  Subclasses can override this for custom initialization behavior.

  The default implementation is empty. Called by `ApplicationObjectSupport.initApplicationContext(org.springframework.context.ApplicationContext)`.

  Overrides:
    `initApplicationContext` in class `ApplicationObjectSupport`
  See Also:
    `ApplicationObjectSupport.setApplicationContext(org.springframework.context.ApplicationContext)`

### getCommand

    protected Object getCommand(javax.portlet.PortletRequest request)
                         throws Exception

  Retrieve a command object for the given request.

  The default implementation calls `createCommand()`. Subclasses can override this.

  Parameters:
    `request` - current portlet request
  Returns:
    object command to bind onto
  Throws:
    `Exception`
  See Also:
    `createCommand()`

### createCommand

    protected final Object createCommand()
                                  throws Exception

  Create a new command instance for the command class of this controller.

  This implementation uses `BeanUtils.instantiateClass`, so the command needs to have a no-arg constructor (supposed to be public, but not required to).

  Returns:
    the new command instance
  Throws:
    `Exception` - if the command object could not be instantiated
  See Also:
    `BeanUtils.instantiateClass(Class)`

### checkCommand

    protected final boolean checkCommand(Object command)

  Check if the given command object is a valid for this controller, i.e. its command class.

  Parameters:
    `command` - the command object to check
  Returns:
    if the command object is valid for this controller

### bindAndValidate

    protected final PortletRequestDataBinder bindAndValidate(javax.portlet.PortletRequest request,
                                                             Object command)
                                                      throws Exception

  Bind the parameters of the given request to the given command object.

  Parameters:
    `request` - current portlet request
    `command` - the command to bind onto
  Returns:
    the PortletRequestDataBinder instance for additional custom validation
  Throws:
    `Exception` - in case of invalid state or arguments

### suppressBinding

    protected boolean suppressBinding(javax.portlet.PortletRequest request)

  Return whether to suppress binding for the given request.

  The default implementation always returns `false`. Can be overridden in subclasses to suppress validation: for example, if a special request parameter is set.

  Parameters:
    `request` - current portlet request
  Returns:
    whether to suppress binding for the given request
  See Also:
    `suppressValidation(javax.portlet.PortletRequest)`

### createBinder

    protected PortletRequestDataBinder createBinder(javax.portlet.PortletRequest request,
                                                    Object command)
                                             throws Exception

  Create a new binder instance for the given command and request.

  Called by `bindAndValidate`. Can be overridden to plug in custom PortletRequestDataBinder instances.

  The default implementation creates a standard PortletRequestDataBinder and invokes `prepareBinder` and `initBinder`.

  Note that neither `prepareBinder` nor `initBinder` will be invoked automatically if you override this method! Call those methods at appropriate points of your overridden method.

  Parameters:
    `request` - current portlet request
    `command` - the command to bind onto
  Returns:
    the new binder instance
  Throws:
    `Exception` - in case of invalid state or arguments
  See Also:
    `bindAndValidate(javax.portlet.PortletRequest, java.lang.Object)`, `prepareBinder(org.springframework.web.portlet.bind.PortletRequestDataBinder)`, `initBinder(javax.portlet.PortletRequest, org.springframework.web.portlet.bind.PortletRequestDataBinder)`

### prepareBinder

    protected final void prepareBinder(PortletRequestDataBinder binder)

  Prepare the given binder, applying the specified MessageCodesResolver, BindingErrorProcessor and PropertyEditorRegistrars (if any). Called by `createBinder`.

  Parameters:
    `binder` - the new binder instance
  See Also:
    `createBinder(javax.portlet.PortletRequest, java.lang.Object)`, `setMessageCodesResolver(org.springframework.validation.MessageCodesResolver)`, `setBindingErrorProcessor(org.springframework.validation.BindingErrorProcessor)`

### useDirectFieldAccess

    protected boolean useDirectFieldAccess()

  Determine whether to use direct field access instead of bean property access. Applied by `prepareBinder`.

  The default is `false`. Can be overridden in subclasses.

  See Also:
    `prepareBinder(org.springframework.web.portlet.bind.PortletRequestDataBinder)`, `DataBinder.initDirectFieldAccess()`

### initBinder

    protected void initBinder(javax.portlet.PortletRequest request,
                              PortletRequestDataBinder binder)
                       throws Exception

  Initialize the given binder instance, for example with custom editors. Called by `createBinder`.

  This method allows you to register custom editors for certain fields of your command class. For instance, you will be able to transform Date objects into a String pattern and back, in order to allow your JavaBeans to have Date properties and still be able to set and display them in an HTML interface.

  The default implementation is empty.

  Parameters:
    `request` - current portlet request
    `binder` - new binder instance
  Throws:
    `Exception` - in case of invalid state or arguments
  See Also:
    `createBinder(javax.portlet.PortletRequest, java.lang.Object)`, `DataBinder.registerCustomEditor(java.lang.Class, java.beans.PropertyEditor)`, `CustomDateEditor`

### onBind

    protected void onBind(javax.portlet.PortletRequest request,
                          Object command,
                          BindException errors)
                   throws Exception

  Callback for custom post-processing in terms of binding. Called on each submit, after standard binding but before validation.

  The default implementation delegates to `onBind(request, command)`.

  Parameters:
    `request` - current portlet request
    `command` - the command object to perform further binding on
    `errors` - validation errors holder, allowing for additional custom registration of binding errors
  Throws:
    `Exception` - in case of invalid state or arguments
  See Also:
    `bindAndValidate(javax.portlet.PortletRequest, java.lang.Object)`, `onBind(PortletRequest, Object)`

### onBind

    protected void onBind(javax.portlet.PortletRequest request,
                          Object command)
                   throws Exception

  Callback for custom post-processing in terms of binding. Called by the default implementation of the `onBind` version with all parameters, after standard binding but before validation.

  The default implementation is empty.

  Parameters:
    `request` - current portlet request
    `command` - the command object to perform further binding on
  Throws:
    `Exception` - in case of invalid state or arguments
  See Also:
    `onBind(PortletRequest, Object, BindException)`

### suppressValidation

    protected boolean suppressValidation(javax.portlet.PortletRequest request)

  Return whether to suppress validation for the given request.

  The default implementation always returns `false`. Can be overridden in subclasses to suppress validation: for example, if a special request parameter is set.

  Parameters:
    `request` - current portlet request
  Returns:
    whether to suppress validation for the given request

### onBindAndValidate

    protected void onBindAndValidate(javax.portlet.PortletRequest request,
                                     Object command,
                                     BindException errors)
                              throws Exception

  Callback for custom post-processing in terms of binding and validation. Called on each submit, after standard binding and validation, but before error evaluation.

  The default implementation is empty.

  Parameters:
    `request` - current portlet request
    `command` - the command object, still allowing for further binding
    `errors` - validation errors holder, allowing for additional custom validation
  Throws:
    `Exception` - in case of invalid state or arguments
  See Also:
    `bindAndValidate(javax.portlet.PortletRequest, java.lang.Object)`, `Errors`

### getRenderCommandSessionAttributeName

    protected String getRenderCommandSessionAttributeName()

  Return the name of the session attribute that holds the render phase command object for this form controller.

  Returns:
    the name of the render phase command object session attribute
  See Also:
    `PortletSession.getAttribute(java.lang.String)`

### getRenderErrorsSessionAttributeName

    protected String getRenderErrorsSessionAttributeName()

  Return the name of the session attribute that holds the render phase command object for this form controller.

  Returns:
    the name of the render phase command object session attribute
  See Also:
    `PortletSession.getAttribute(java.lang.String)`

### getRenderCommand

    protected final Object getRenderCommand(javax.portlet.RenderRequest request)
                                     throws javax.portlet.PortletException

  Get the command object cached for the render phase.

  Throws:
    `javax.portlet.PortletException`
  See Also:
    `getRenderErrors(javax.portlet.RenderRequest)`, `getRenderCommandSessionAttributeName()`, `setRenderCommandAndErrors(javax.portlet.ActionRequest, java.lang.Object, org.springframework.validation.BindException)`

### getRenderErrors

    protected final BindException getRenderErrors(javax.portlet.RenderRequest request)
                                           throws javax.portlet.PortletException

  Get the bind and validation errors cached for the render phase.

  Throws:
    `javax.portlet.PortletException`
  See Also:
    `getRenderCommand(javax.portlet.RenderRequest)`, `getRenderErrorsSessionAttributeName()`, `setRenderCommandAndErrors(javax.portlet.ActionRequest, java.lang.Object, org.springframework.validation.BindException)`

### setRenderCommandAndErrors

    protected final void setRenderCommandAndErrors(javax.portlet.ActionRequest request,
                                                   Object command,
                                                   BindException errors)
                                            throws Exception

  Set the command object and errors object for the render phase.

  Parameters:
    `request` - the current action request
    `command` - the command object to preserve for the render phase
    `errors` - the errors from binding and validation to preserve for the render phase
  Throws:
    `Exception`
  See Also:
    `getRenderCommand(javax.portlet.RenderRequest)`, `getRenderErrors(javax.portlet.RenderRequest)`, `getRenderCommandSessionAttributeName()`, `getRenderErrorsSessionAttributeName()`

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