AjaxResetButton.java

package er.ajax;

import com.webobjects.appserver.WOComponent;
import com.webobjects.appserver.WOContext;
import com.webobjects.appserver.WOResponse;

/**
 * Simple submit button wrapper around Prototypes Form.reset('formID');.  Does a client side
 * reset (to original values or to blank / no selection) of all of a form's inputs.
 * 
 * @binding formId String, the id of the form to be reset
 * @binding clear boolean, true if the form values should be cleared, false should be reset to original values
 * @binding value String, optional label for the button, the default is Reset
 * @binding id, String, optional HTML ID for the button element
 * @binding class, String, optional CSS class name for the button element
 * @binding style, String, optional CSS style definition for the button element
 *
 * @author Chuck Hill
 */
public class AjaxResetButton extends WOComponent {
	/**
	 * Do I need to update serialVersionUID?
	 * See section 5.6 <cite>Type Changes Affecting Serialization</cite> on page 51 of the 
	 * <a href="http://java.sun.com/j2se/1.4/pdf/serial-spec.pdf">Java Object Serialization Spec</a>
	 */
	private static final long serialVersionUID = 1L;

    public static final String FORM_ID_BINDING = "formId";
    public static final String VALUE_BINDING = "value";
    public static final String CLEAR_BINDING = "clear";
    
    public AjaxResetButton(WOContext context) {
        super(context);
    }
    
    /**
     * @return <code>true</code>
     */
    @Override
    public boolean isStateless() {
        return true;
    }
    
    /**
     * Adds prototype.js to the header.
     */
    @Override
    public void appendToResponse(WOResponse response, WOContext context) {
        super.appendToResponse(response, context);
        AjaxUtils.addScriptResourceInHead(context, response, "prototype.js");
    	AjaxUtils.addScriptResourceInHead(context, response, "effects.js");
        AjaxUtils.addScriptResourceInHead(context, response, "wonder.js");
    }
    
    /**
     * @return JavaScript to reset form
     */
    public String resetFormJavaScript() {
		// PROTOTYPE FUNCTIONS
    	return clear() ? "Form.clear('" + formId() + "'); return false;" : "Form.reset('" + formId() + "'); return false;";
    }
    
    /**
     * @return value of formId binding
     */
    public String formId() {
        if ( ! hasBinding(FORM_ID_BINDING)) {
            throw new IllegalArgumentException(FORM_ID_BINDING + " is a required binding");
        }

        return (String) valueForBinding(FORM_ID_BINDING);
    }
    
    /**
     * @return value of value binding
     */
    public String value() {
        return hasBinding(VALUE_BINDING) ? (String) valueForBinding(VALUE_BINDING) : "Reset";
    }
    
    /**
     * @return value of value binding
     */
    public boolean clear() {
        return hasBinding(CLEAR_BINDING) ? ((Boolean)valueForBinding(CLEAR_BINDING)).booleanValue() : false;
    }
    
    /**
     * This should never be called.  If it gets called, something went wrong with the onClick event on 
     * the button.
     * 
     * @return current page
     */
    public WOComponent dummy() {
    	throw new RuntimeException("Action called.  This can happen if your formId binding is not correct");
    }
    
}