/*
    * Copyright 2004-2009 the original author or authors.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.springmodules.validation.commons;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Locale;
  
  import org.apache.commons.validator.Form;
  import org.apache.commons.validator.Validator;
  import org.apache.commons.validator.ValidatorResources;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.beans.FatalBeanException;
  import org.springframework.beans.factory.InitializingBean;
  import org.springframework.core.io.Resource;
  import org.springframework.util.StringUtils;
  import org.springframework.validation.Errors;
  import org.xml.sax.SAXException;
  
  /**
   * @author Daniel Miller
   * @author Rob Harrop
   */
  public class DefaultValidatorFactory implements ValidatorFactory, InitializingBean {
  
      /**
       * Key used to store the Spring <code>Errors</code> instance in the <code>Validator</code>
       */
      public static final String ERRORS_KEY = "org.springframework.validation.Errors";
  
      /**
       * The <code>Log</code> instance used by this class.
       */
      private static Logger log = LoggerFactory.getLogger(DefaultValidatorFactory.class);
  
      /**
       * the Commons Validator <code>ValidatorResources</code> used to load validation configuration.
       */
      private ValidatorResources validatorResources;
  
      /**
       * Checks that the <code>ValidatorResources</code> exists and has been configured with resources
       * via a call to <code>setValidationConfigLocations</code>.
       *
       * @throws org.springframework.beans.FatalBeanException if <code>setValidationConfigLocations()</code> has not been called.
       */
      public void afterPropertiesSet() throws Exception {
          if (this.validatorResources == null) {
              throw new FatalBeanException("Unable to locate validation configuration. Property [validationLocations] is required.");
          }
      }
  
      /**
       * Sets the locations of the validation configuration files from which to load validation rules. Creates an instance
       * of <code>ValidatorResources</code> from the specified configuration files.
       *
       * @see org.springframework.core.io.Resource
       * @see ValidatorResources
       */
      public void setValidationConfigLocations(Resource[] validationConfigLocations) {
  
          if (DefaultValidatorFactory.log.isInfoEnabled()) {
              DefaultValidatorFactory.log.info("Loading validation configurations from [" + StringUtils.arrayToCommaDelimitedString(validationConfigLocations) + "]");
          }
  
          try {
              InputStream[] inputStreams = new InputStream[validationConfigLocations.length];
  
              for (int i = 0; i < inputStreams.length; i++) {
                  inputStreams[i] = validationConfigLocations[i].getInputStream();
              }
  
              this.validatorResources = new ValidatorResources(inputStreams);
          }
          catch (IOException e) {
              throw new FatalBeanException("Unable to read validation configuration due to IOException.", e);
          }
          catch (SAXException e) {
              throw new FatalBeanException("Unable to parse validation configuration XML", e);
          }
      }
  
      /**
       * Gets a new instance of a <code>org.apache.commons.validator.Validator</code> for the given bean.
      *
      * @param beanName The name of the bean for which this <code>Validator</code> will be created
      * @see org.apache.commons.validator.Validator
      */
     public Validator getValidator(String beanName, Object bean, Errors errors) {
         Validator validator = new Validator(validatorResources, beanName);
         validator.setParameter(DefaultValidatorFactory.ERRORS_KEY, errors);
         validator.setParameter(Validator.BEAN_PARAM, bean);
         return validator;
     }
 
 
     /**
      * Returns true if this validator factory can create a validator that
      * supports the given <code>beanName</code> and <code>locale</code>.
      *
      * @param beanName name of the bean to be validated.
      * @param locale <code>Locale</code> to search under.
      * @return <code>true</code> if this validator factory can create a validator for
      *         the given bean name, <code>false otherwise.
      */
     public boolean hasRulesForBean(String beanName, Locale locale) {
         Form form = validatorResources.getForm(locale, beanName);
         return (form != null);
     }
 
     /**
      * Gets the managed instance of <code>ValidatorResources</code>.
      */
     public ValidatorResources getValidatorResources() {
         return validatorResources;
     }
 
 }