/*
* (c) Copyright 2006-2011 by Volker Bergmann. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, is permitted under the terms of the
* GNU General Public License.
*
* For redistributing this software or a derivative work under a license other
* than the GPL-compatible Free Software License as defined by the Free
* Software Foundation or approved by OSI, you must first obtain a commercial
* license to this software product from Volker Bergmann.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
* REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
* HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package org.databene.benerator.util;
import org.databene.benerator.IllegalGeneratorStateException;
import org.databene.benerator.wrapper.ProductWrapper;
import org.databene.commons.Validator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Provides an abstract implementation of a generator that validates its generated values.<br/>
* <br/>
* Created: 23.09.2006 00:03:04
* @since 0.1
* @author Volker Bergmann
*/
public abstract class ValidatingGenerator<P> extends AbstractGenerator<P> {
/** The Logger */
private static Logger logger = LoggerFactory.getLogger(ValidatingGenerator.class);
/** The number of invalid consecutive generations that causes a warning */
public static final int WARNING_THRESHOLD = 100;
/** The number of invalid consecutive generations that causes an exception */
public static final int ERROR_THRESHOLD = 1000;
/** The validator used for validation */
protected Validator<P> validator;
/** Constructor that takes the validator */
public ValidatingGenerator(Validator<P> validator) {
this.validator = validator;
}
/**
* Generator implementation that calls generateImpl() to generate values
* and validator.validate() in order to validate them.
* Consecutive invalid values are counted. If this count reaches the
* WARNING_THRESHOLD value, a warning is logged, if the count reaches the
* ERROR_THRESHOLD, an exception is raised.
*/
public ProductWrapper<P> generate(ProductWrapper<P> wrapper) {
boolean valid;
int count = 0;
P product;
do {
wrapper = doGenerate(wrapper);
if (wrapper == null)
return null;
product = wrapper.unwrap();
valid = validator.valid(product);
count++;
if (count >= ERROR_THRESHOLD)
throw new IllegalGeneratorStateException("Aborting generation, because of " + ERROR_THRESHOLD
+ " consecutive invalid generations. Validator is: " + validator +
". Last attempt was: " + product);
} while (!valid);
if (count >= WARNING_THRESHOLD)
logger.warn("Inefficient generation: needed " + count + " tries to generate a valid value. ");
return wrapper.wrap(product);
}
/**
* Callback method that does the job of creating values.
* This is to be implemented by child classes.
*/
protected abstract ProductWrapper<P> doGenerate(ProductWrapper<P> wrapper);
}