JSF Converter for MT Comments.

I've been working on a JSF front end to my blog lately, and needed to display comments. My first instinct was to create a new JSF component, and although that would be a bit of fun, I decided to just create a converter and use an existing ADF Faces component. I am simply displaying the comments in an outputText, using my Moveable Type converter.

The converter simply replaces each line of the comment with <p>line</p>

If you haven't created a JSF converter before, it's really simple and here are the steps:

1. Create a class that implements javax.faces.convert.Converter.
2. register your converter with your faces-config.xml file.
3. Call your converter in your view.

Here is the Converter source:

package org.robsite.adfblog.view;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;

import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;

import oracle.adf.view.faces.context.AdfFacesContext;
import oracle.adf.view.faces.context.Agent;


/**
 * Movable Type comment converter.  
 * Wraps a comment from Moveble Type (stored in the database as plain text, 
 * with CR/LF line endings with html paragraph tags for proper display in a 
 * web page.  
 * Note: If ADF Faces is in use, the conversion will only happen if the 
 * ADF Faces's device type is a desktop device.
 */
public class MtCommentConverter implements Converter {
    private boolean wrapComment;
    
    public MtCommentConverter() {
        try {
            Agent agent = AdfFacesContext.getCurrentInstance().getAgent();
            wrapComment = ( agent.getType() == Agent.TYPE_DESKTOP );
        }
        catch (Exception e) {
            wrapComment = true;
        }
    }

    public Object getAsObject(FacesContext context, 
                              UIComponent component, String s) {
        return s;
    }

    public String getAsString(FacesContext context, 
                              UIComponent component, Object o) {
        if ( wrapComment && o instanceof String)
        {
            final String commentRaw = (String)o;
            try {
                BufferedReader reader = new BufferedReader( new StringReader( commentRaw ) );
                
                final StringBuilder sb = new StringBuilder( (int)(commentRaw.length() * 1.2 ) );
                for( String line = reader.readLine(); line != null; ) {
                    sb.append( "<p>" + line + "</p>" );
                    line = reader.readLine();
                    if ( line == null ) {
                        reader.close();
                    }
                }
                return sb.toString();
            }
            catch (IOException e) {
                return commentRaw;
            }
        }
        return o.toString();
    }
}

 

Now you need to add an entry into your faces-config.xml file:

  <converter>
    <converter-id>org.robsite.adfblog.view.MtCommentConverter</converter-id>
    <converter-class>org.robsite.adfblog.view.MtCommentConverter</converter-class>
  </converter>

 

Now finally add the tag into your output tag in your JSP or JSPX page:

            <af:outputText value="#{row.commentText}"
                            escape="false">
              <f:converter converterId="org.robsite.adfblog.view.MtCommentConverter" />
            </af:outputText>

 

Posted by rcleveng at January 30, 2006 04:22 PM

Comments

Post a comment

Name:

Email Address:

URL:
Remember Me? YesNo

Comments: