BaseValidationService.java :  » Development » iScreen » org » iscreen » impl » Java Open Source

/*
 * Copyright 2006-2007 Dan Shellman
 *
 * 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.iscreen.impl;


import java.util.List;
import java.util.Locale;
import org.iscreen.DocumentationIterator;
import org.iscreen.ObjectValidationException;

import org.iscreen.ValidationException;
import org.iscreen.ValidationService;

/**
 * This is the base class implementation of the ValidationService interface.
 *
 * @author Shellman, Dan
 */
public abstract class BaseValidationService implements ValidationService
{
  protected String                id;
  protected Locale                defaultLocale;


  /**
   * Constructor taking unique id.  The unique id is required.  In addition,
   * the default locale is provided.
   *
   * @param   uniqueId The unique id for this service.
   * @param   locale The default locale for this service.
   */
  public BaseValidationService( String uniqueId, Locale locale )
  {
    id = uniqueId;
    defaultLocale = locale;
  } //end BaseValidationService()

  public void validate( Object obj ) throws ValidationException
  {
    validate( obj, defaultLocale );
  } //end validate()

  public void validate( Object obj, Locale locale ) throws ValidationException
  {
    ContextBean               contextBean;
    DefaultValidatorContext   context;
    ValidatorWrapper          wrapper;
    List                      failures;

    //Basic algorithm:
    //Loop through validators and perform the following:
    // -Initialize an ContextBean and ValidatorContext
    // -Call the validator wrapper's validate() method with context and bean
    // -Store any validation failures
    //Once done looping through validators, if there are more than zero
    //validation failures, create a ValidationException, stuff the validation
    //failures in there, and throw it.  Otherwise, return.
    contextBean = constructContextBean( obj );
    context = constructContext( contextBean, locale );

    resetValidatorIteration();
    wrapper = getNextValidator();
    while ( wrapper != null )
    {
      boolean                 continueFlag;

      context.setValidator( wrapper );
      continueFlag = wrapper.validate( context, contextBean, obj );
      if ( continueFlag == false )
      {
        break;
      }

      wrapper = getNextValidator();
    }

    //Finally, check to see if there were any failures.
    if ( context.getCount() > 0 )
    {
      throw new ValidationException( context.getFailures(),
                                     context.getWarnings() );
    }
  } //end validate()

  public void validateObject( Object obj, Locale locale )
  {
    try
    {
      validate( obj, locale );
    }
    catch ( ValidationException e )
    {
      throw new ObjectValidationException( e );
    }
  } //end validateObject()
  
  public void validateObject( Object obj )
  {
    validateObject( obj, defaultLocale );
  } //end validateObject()

  public String getServiceName()
  {
    return id;
  } //end getServiceName()

  /**
   * Retrieves an iterator of String values representing the documentation
   * configured for this validation service (the underlying validation set).
   *
   * @return Returns an iterator of Strings representing documentation.
   */
  public DocumentationIterator getDocumentation()
  {
    DocumentationIterator           docIt = new DocumentationIterator();
    ValidatorWrapper                wrapper;

    resetValidatorIteration();
    wrapper = getNextValidator();
    while ( wrapper != null )
    {
      docIt.addIterator( wrapper.getDoc() );

      wrapper = getNextValidator();
    }

    return docIt;
  } //end getDocumentation()


// ***
// Protected methods
// ***
  
  
  /**
   * Retrieves the "next" Validator in the set of Validators that this
   * validation service is configured to use.  If there are no more
   * Validators, then this method should return null.  It should return
   * the first Validator after a call to resetValidatorIteration().
   *
   * @return Returns the next ValidatorWrapper in the set of validators.
   */
  protected abstract ValidatorWrapper getNextValidator();
  
  /**
   * Resets the iteration of Validators using the getNextValidator() method.
   */
  protected abstract void resetValidatorIteration();
  
  /**
   * This can be over-written by sub-classes, but it's not really necessary,
   * since this service requires a particular implementation of the
   * ValidatorContext.
   * 
   * 
   * @param root The ContextBean that the context needs.
   * @param locale The locale to use in generating error messages.
   * @return Returns a constructed and configured DefaultValidatorContext.
   */
  protected DefaultValidatorContext constructContext( ContextBean root, Locale locale )
  {
    return new DefaultValidatorContext( root, locale );
  } //end constructContext()
  
  /**
   * This can be over-written by sub-classes, but it's not really necessary,
   * since this service requires an OGNL root object.
   * 
   * 
   * @return Returns an instance of ContextBean fully configured.
   */
  protected ContextBean constructContextBean( Object objToValidate )
  {
    ContextBean                root;

    root = new ContextBean();
    root.setBean( objToValidate );

    return root;
  } //end constructContextBean()
} //end BaseValidationService