DynamicValidatorUtil.java

package org.jboss.errai.validation.client.dynamic;

import java.util.Map;

import javax.validation.Constraint;

import com.google.gwt.regexp.shared.MatchResult;
import com.google.gwt.regexp.shared.RegExp;

public class DynamicValidatorUtil {

  private DynamicValidatorUtil() {};
  
  private static final RegExp messageParamsExp = RegExp.compile("{([A-Za-z]+)}");
  
  /**
   * Interpolates a constraint violation message.
   * 
   * @param parameters
   *          A map of values for all properties for the {@link Constraint} associated with this validator.
   * @param template
   *          the message template.
   * @return the interpolated message, or an empty String if template is null.
   */
  public static String interpolateMessage(Map<String, Object> parameters, String template) {
    if (template == null) {
      return "";
    }
    
    MatchResult result;
    String message = template;
    
    while ((result = messageParamsExp.exec(message)) != null) {
      final String name = result.getGroup(1);
      final Object value = parameters.get(name);
      final String strValue = (value!= null) ? value.toString() : "";
      message = message.replaceAll("{" + name + "}", strValue);
    }
    
    return message;
  }
}