com.oopreserch.web
Interface FormValueEscaper

All Known Implementing Classes:

EscapeForHdml, EscapeForHtml, UrlEncodeAscii, EscapeForWml, EscapeForXml

public interface FormValueEscaper

The interface for getting the escaped String.

On the instance of Form, you can insert the arbitrary String into the pre-defined code fragments. Then, the instance of Form can merge them all and return the concatenated String.

For example, the String selected from SQL table can be inserted into the HTML table. In this case, the HTML tags for the HTML table skeleton will be written as the pre-defined code fragments.
Please consider what will happen if the String to be inserted includes the special characters such as < or >. The concatenated String will be invalid as the HTML code, which will result in the corrupted String on the web browser.

To avoid such a problems, the String to be inserted should be escaped, i.e. all the special characters within the original String should be replaced with the corresponding escaped characters. And this is the responsibility of the implementation of this interface.

The implementation of this interface will be used by the instance of Form to escape the String to be inserted. The list of the available implementations should be listed in:

• (docBase)/WEB-INF/classes/FormValueEscaperFactory.properties

where the value of each property is the fully qualified class name of the implementation of this interface. The key in this property resource file can be specified as the value of escape.type attribute of d.value element in the XML. Then, the corresponding implementation will be used to escape the String to be inserted.

The implementation of this interface must implement:

• no-argument public constructor
• getEscaped(String)

The special characters to be escaped differ with the mark-up-languages. In case of HTML, at least the following characters should be escaped:

Original Character	Escaped Character
<	&lt;
>	&gt;
&	&amp;

In addition, " and $ should be also replaced with &quot; and &dol; in HDML.

In XML, the following characters should be escaped:

Original Character	Escaped Character
<	&lt;
>	&gt;
&	&amp;
"	&quot;
'	&apos;

As for WML, $ should also be replaced with $$. (See Page 6 of WML Language Reference which is available at OpenWave's web site.)

Anyway, the 4 implementations are included in this package. They are:

• EscapeForHtml
• EscapeForHdml
• EscapeForXml
• EscapeForWml

So, please feel free to use any of them. Or, if you need additional features, you can define your own implementation which satisfies your requirement. In this case, please add the fully qualified class name of your implementation to:

• (docBase)/WEB-INF/classes/FormValueEscaperFactory.properties

For details about this property resource file, please look into FormValueEscaperFactory.

Occasionally, you may want to URL-encode the String to be inserted. To specify the charset by which the String is URL-encoded, please define your own implementation of this interface. For example, if you'd like to URL-encode the String by EUC-JP, you need to define such an implementation of this interface. To make your life easier, the class for ISO-8859-1 is included in this package. It is:

• UrlEncodeAscii

By extending this class, you can easily define your implementation. All you have to do is to override the value of:

    protected String charset="ISO-8859-1";
 

within your subclass. The constructor will be the good place for this task. For your convenience, the following 2 classes are included in this package:

• UrlEncodeUtf8
• UrlEncodeShiftJis

All of these are the just the subclass of the above class, and you can define your own subclasses.

For details, please visit Introduction of FormGenerator, which shows how to implement this interface.

Since:

2.0

Author:

Jun Inamori

See Also:





Method Summary

java.lang.String

getEscaped(java.lang.String str) This method will be used by Form to escape the String to be inserted.

Method Detail

getEscaped

public java.lang.String getEscaped(java.lang.String str)

This method will be used by Form to escape the String to be inserted.

The implementation of this method is responsible for escaping the special characters in the given String. Or, it may URL-encode the given String. This method must be Thread Safe in all the implementations.

Parameters:

str - The String to be escaped.

Returns:

The escaped String

Since:

2.0