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StrutsTypeConverter.javaAPI DocExample3785Mon Jul 23 13:26:56 BST 2007org.apache.struts2.util

StrutsTypeConverter

public abstract class StrutsTypeConverter extends ognl.DefaultTypeConverter
Base class for type converters used in Struts. This class provides two abstract methods that are used to convert both to and from strings -- the critical functionality that is core to Struts's type coversion system.

Type converters do not have to use this class. It is merely a helper base class, although it is recommended that you use this class as it provides the common type conversion contract required for all web-based type conversion.

There's a hook (fall back method) called performFallbackConversion of which could be used to perform some fallback conversion if convertValue method of this failed. By default it just ask its super class (Ognl's DefaultTypeConverter) to do the conversion.

To allow the framework to recognize that a conversion error has occurred, throw an XWorkException or preferable a TypeConversionException.

Fields Summary
Constructors Summary
Methods Summary
public abstract java.lang.ObjectconvertFromString(java.util.Map context, java.lang.String[] values, java.lang.Class toClass)
Converts one or more String values to the specified class.

param
context the action context
param
values the String values to be converted, such as those submitted from an HTML form
param
toClass the class to convert to
return
the converted object

public abstract java.lang.StringconvertToString(java.util.Map context, java.lang.Object o)
Converts the specified object to a String.
param
context the action context
param
o the object to be converted
return
the converted String
public java.lang.ObjectconvertValue(java.util.Map context, java.lang.Object o, java.lang.Class toClass)
        if (toClass.equals(String.class)) {
            return convertToString(context, o);
        } else if (o instanceof String[]) {
            return convertFromString(context, (String[]) o, toClass);
        } else if (o instanceof String) {
            return convertFromString(context, new String[]{(String) o}, toClass);
        } else {
            return performFallbackConversion(context, o, toClass);
        }
    
protected java.lang.ObjectperformFallbackConversion(java.util.Map context, java.lang.Object o, java.lang.Class toClass)
Hook to perform a fallback conversion if every default options failed. By default
this will ask Ognl's DefaultTypeConverter (of which this class extends) to
perform the conversion.
param
context
param
o
param
toClass
return
The fallback conversion
        return super.convertValue(context, o, toClass);