atg.droplet

Class TagConverterManager

java.lang.Object

atg.droplet.TagConverterManager

public class TagConverterManager
extends java.lang.Object

This class contains a set of static methods which you can use to register and use TagConverters. TagConverters are used to perform String to Object and Object to String conversion in the valueof, input and param tags.

To add your own converter, follow these steps:

• Create a new class which implements the TagConverter interface. This class must implement four methods:

  • getName

    Returns the name of your converter. This is the name that is used as an argument to the converter attribute in a tag. For example, if your getName method returned "currency", you'd define a tag like:

    <valueof param="myPrice" converter="currency" >

  • getTagAttributeDescriptors

    Returns the list of attribute arguments that this converter takes. These attributes are just listed along with the "converter" attribute in your valueof, input, or param tag. These attributes can mark themselves as optional if they are not required. For example, the currency converter above might take a locale attribute which is optional (the default behavior if this attribute is missing would be to use the locale associated with the current request).

    A TagAttributeDescriptor also can mark itself as "automatic" which means that this attribute implies the use of this converter, even if the converter attribute is not specified. For example, if the currency converter defined a "currency" attribute that was automatic, you can use this converter in your page with:

    <valueof param="myPrice" currency >

    It is an error to have more than one converter registered with the same automatic attribute. You can replace an existing converter by registering a new one with the same name (after the existing converter has already been registered).

    It is legal to define a TagConverter which takes the same attribute as another TagConverter as long as it is not ambiguous which converter to use for a given tag. The "required" attribute is an automatic attribute for the RequiredTagConverter. The DateTagConverter has "date" as an automatic attribute and "required" as an optional attribute. If you use both "date" and "required" in the same tag, the DateTagConverter is used. If you use just "required", the RequiredTagConverter is used.

  • convertStringToObject

    This method is called in two circumstances. If you are using an input tag, when that form value is submitted, this method is called before the setX method of your bean is called. It is the job of your convertStringToObject method to generate the Object value for use in the setX method. It can throw a TagConversionException if an error occurs during the conversion process. This method is also called if you use this converter with a param tag when the value of the parameter is defined.

  • convertObjectToString

    This method is called in two situations. When you use a converter in a valueof tag, this method is used to convert the Object value into a String value before displaying it. Also, when you use this tag in an input tag with a bean attribute and no existing value attribute, this method is called to fill in the value attribute with the current value of the bean property.
• Call the TagConverterManager.registerTagConverter method with an instance of this class. Note that this call must be made before your converter is used by a jhtml page. Make sure that you add this code to a class which gets initialized during the startup process of your server (i.e. is in the Initial services list).
• Add a <valueof>, <input>, or <param> tag to the page which uses this converter.

See Also:

TagConverter

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	CLASS_VERSION
static java.lang.Object	SET_AS_NULL

Constructor Summary

Constructors

Constructor and Description
TagConverterManager()

Method Summary

Modifier and Type	Method and Description
static java.lang.Object	convertStringToObject(TagConverter pCvt, DynamoHttpServletRequest pReq, java.lang.String pValue, java.util.Properties pAttributes) This method converts Strings to Objects swallowing the conversion exception so that it can be used in a class constructor.
static TagConverter	getTagConverterByAttribute(java.lang.String pAttributeName) Returns the TagConverter registered for a specific attribute name.
static TagConverter	getTagConverterByName(java.lang.String pConverterName) Returns the TagConverter for a specified set of attributes.
static boolean	isTagAttribute(TagConverter pCvt, java.lang.String pAttributeName) Returns true if this is an attribute (either required or optional) for this converter.
static void	registerTagConverter(TagConverter pConverter) Adds a new TagConverter to the global list of converters.

Methods inherited from class java.lang.Object

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

Field Detail

CLASS_VERSION

public static java.lang.String CLASS_VERSION

SET_AS_NULL

public static final java.lang.Object SET_AS_NULL

Constructor Detail

TagConverterManager

public TagConverterManager()

Method Detail

registerTagConverter

public static void registerTagConverter(TagConverter pConverter)

Adds a new TagConverter to the global list of converters. Converters are registered by name as specified in their getName method. If a converter of an existing name is already registered, this mechanism replaces that converter with this new converter.

getTagConverterByName

public static TagConverter getTagConverterByName(java.lang.String pConverterName)

Returns the TagConverter for a specified set of attributes. If no applicable converter is found, null is returned.

getTagConverterByAttribute

public static TagConverter getTagConverterByAttribute(java.lang.String pAttributeName)

Returns the TagConverter registered for a specific attribute name. If no converter is registered for that attribute, null is returned.

isTagAttribute

public static boolean isTagAttribute(TagConverter pCvt,
                                     java.lang.String pAttributeName)

Returns true if this is an attribute (either required or optional) for this converter.

convertStringToObject

public static java.lang.Object convertStringToObject(TagConverter pCvt,
                                                     DynamoHttpServletRequest pReq,
                                                     java.lang.String pValue,
                                                     java.util.Properties pAttributes)

This method converts Strings to Objects swallowing the conversion exception so that it can be used in a class constructor. It is only intended to be used in code generated by the PageCompiler.

The pReq argument can be null if there is no request with which to implement the conversion. If you are using the request to access the locale with which to perform the conversion, use the default locale in this case.