net.sf.jguiraffe.transform

Class DefaultValidationMessageHandler

java.lang.Object

net.sf.jguiraffe.transform.DefaultValidationMessageHandler

All Implemented Interfaces:

ValidationMessageHandler

public class DefaultValidationMessageHandler
extends Object
implements ValidationMessageHandler

A default implementation of the ValidationMessageHandler interface.

This class performs the following steps for obtaining a ValidationMessage object for a given key:

• It checks whether the passed in TransformerContext contains a property with the name of the given key. If this is the case, its value will be used as error message. This makes it possible to override validation messages directly in the builder script when the validator is defined.
• Otherwise the error message will be loaded from the application's resources using the key as resource ID. For the resource group the following options exist:
  • With the setAlternativeResourceGroups(String) method a list of resource groups can be set, which will be searched for resources with message keys. So an application can define a custom resource group containing the error messages it wants to override and specify it here.
  • If the resource for the message key cannot be found in one of the alternative resource groups, the resource group returned by the getDefaultResourceGroup() method will be used. If not otherwise set, the name defined by the DEFAULT_RESOURCE_GROUP_NAME constant is used. This is a resource group shipped with the framework, which contains default validation messages in a couple of supported languages.

DefaultValidationMessageHandler also determines the ValidationMessageLevel of the messages it returns. This is done by evaluating the errorLevel property of the passed in TransformerContext. If this property is set, its value is interpreted as an enumeration literal defined by the ValidationMessageLevel class. If the property is undefined, the default message level ValidationMessageLevel.ERROR is used. The advantage behind this concept is that the message level is completely transparent for validators. So they can produce messages of any level, provided that the TransformerContext is properly configured.

The ValidationMessage objects returned by this object are thread-safe; they can be concurrently accessed without requiring further synchronization.

Version:

$Id: DefaultValidationMessageHandler.java 205 2012-01-29 18:29:57Z oheger $

Author:

Oliver Heger

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_RESOURCE_GROUP_NAME Constant for the default resource group with validation messages.
static String	PROP_MESSAGE_LEVEL Constant for the name of the property that defines the ValidationMessageLevel of the validation messages produced by this object.

Constructor Summary

Constructors

Constructor and Description
DefaultValidationMessageHandler() Creates a new instance of DefaultValidationMessageHandler.

Method Summary

Modifier and Type	Method and Description
String	getAlternativeResourceGroups() Returns the alternative resource groups.
String	getDefaultResourceGroup() Returns the name of the default resource group.
protected ValidationMessageLevel	getMessageLevel(TransformerContext context) Determines the ValidationMessageLevel for the validation messages produced by this object.
ValidationMessage	getValidationMessage(TransformerContext context, String key, Object... params) Returns a validation message.
void	setAlternativeResourceGroups(String alternativeResourceGroups) Sets the alternative resource groups.
void	setDefaultResourceGroup(String defaultResourceGroup) Sets the name of the default resource group.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_RESOURCE_GROUP_NAME

public static final String DEFAULT_RESOURCE_GROUP_NAME

Constant for the default resource group with validation messages. This group name will be used if no specific default resource group has been set.

See Also:

Constant Field Values

PROP_MESSAGE_LEVEL

public static final String PROP_MESSAGE_LEVEL

Constant for the name of the property that defines the ValidationMessageLevel of the validation messages produced by this object. This property can be set in the properties of the TransformerContext.

See Also:

Constant Field Values

Constructor Detail

DefaultValidationMessageHandler

public DefaultValidationMessageHandler()

Creates a new instance of DefaultValidationMessageHandler.

Method Detail

getDefaultResourceGroup

public String getDefaultResourceGroup()

Returns the name of the default resource group.

Returns:

the name of the default resource group

setDefaultResourceGroup

public void setDefaultResourceGroup(String defaultResourceGroup)

Sets the name of the default resource group. This group will be searched for resources for validation messages if the search in the alternative resource groups yielded no results. If no default resource group was set, the group defined by the DEFAULT_RESOURCE_GROUP_NAME constant is used.

Parameters:

defaultResourceGroup - the new default resource group

See Also:

setAlternativeResourceGroups(String)

getAlternativeResourceGroups

public String getAlternativeResourceGroups()

Returns the alternative resource groups.

Returns:

the alternative resource groups

setAlternativeResourceGroups

public void setAlternativeResourceGroups(String alternativeResourceGroups)

Sets the alternative resource groups. This method expects a comma separated string with names of resource groups to be searched for validation messages. If, for instance, the string "specialMessages, extendedMessages" is passed in, the text for a validation message will be searched first in the group "specialMessages", then in the group "extendedMessages", and finally in the default resource group. It is possible to set the alternative resource groups to null. Then only the default resource group will be searched.

Parameters:

alternativeResourceGroups - a comma separated list of alternative resource groups

getValidationMessage

public ValidationMessage getValidationMessage(TransformerContext context,
                                              String key,
                                              Object... params)

Returns a validation message. This method implements the steps described in the class comment for obtaining a validation message for the given key.

Specified by:

getValidationMessage in interface ValidationMessageHandler

Parameters:

context - the transformer context (must not be null)

key - the key of the message (must not be null)

params - additional parameters to be integrated into the message

Returns:

the validation message object for this key

Throws:

IllegalArgumentException - if the transformer context or the key are null

getMessageLevel

protected ValidationMessageLevel getMessageLevel(TransformerContext context)

Determines the ValidationMessageLevel for the validation messages produced by this object. This implementation tests whether in the TransformerContext the PROP_MESSAGE_LEVEL property is set. If so, its value is evaluated. Otherwise the default level ValidationMessageLevel.ERROR is returned.

Parameters:

context - the TransformerContext

Returns:

the ValidationMessageLevel