regexvalidatortag.java

struts框架的jsf组件的核心实用例子集合

package com.corejsf;

import javax.faces.application.Application;
import javax.faces.context.FacesContext;
import javax.faces.validator.Validator;
import javax.faces.webapp.UIComponentTag;
import javax.faces.webapp.ValidatorTag;
import javax.servlet.jsp.JspException;

public class RegexValidatorTag extends ValidatorTag {
   private String expression;
   private String errorSummary;
   private String errorDetail;

   public RegexValidatorTag() {
      setValidatorId("com.corejsf.Regex");
   }

   // PROPERTY: expression
   public void setExpression(String newValue) { 
      expression = newValue;
   } 

   // PROPERTY: errorSummary
   public void setErrorSummary(String newValue) { 
      errorSummary = newValue;
   } 

   // PROPERTY: errorDetail
   public void setErrorDetail(String newValue) { 
      errorDetail = newValue;
   } 

   public Validator createValidator() throws JspException {
      RegexValidator validator = (RegexValidator) super.createValidator();

      validator.setExpression(eval(expression));
      validator.setErrorSummary(eval(errorSummary));
      validator.setErrorDetail(eval(errorDetail));

      return validator;
   }

   public void release() {
      expression = null;
      errorSummary = null;
      errorDetail = null;
   }
   
   public static String eval(String expression) {
      if (expression != null && UIComponentTag.isValueReference(expression)) {
         FacesContext context = FacesContext.getCurrentInstance();
         Application app = context.getApplication();
         return "" + app.createValueBinding(expression).getValue(context);
      }
      else return expression;      
   } 
}