/*
* Copyright (c) 2012 Data Harmonisation Panel
*
* All rights reserved. This program and the accompanying materials are made
* available under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the License,
* or (at your option) any later version.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution. If not, see <http://www.gnu.org/licenses/>.
*
* Contributors:
* HUMBOLDT EU Integrated Project #030962
* Data Harmonisation Panel <http://www.dhpanel.eu>
*/
package eu.esdihumboldt.util.validator;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
/**
* Validator that only checks whether one of its known validators validate the
* given input.
*
* @author Kai Schwierczek
*/
public class OrValidator implements CombinedValidator {
private final LinkedList<Validator> validators = new LinkedList<Validator>();
/**
* Constructs an OrValidator with the given validators.
*
* @param validators the validators.
*/
public OrValidator(Collection<Validator> validators) {
// if one validator is always true, only keep it and forget the rest.
boolean alwaysTrue = false;
for (Validator validator : validators)
if (validator.isAlwaysTrue()) {
alwaysTrue = true;
this.validators.add(validator);
break;
}
if (!alwaysTrue)
this.validators.addAll(validators);
}
/**
* Adds the given Validator to this Validator.<br>
* OrValidators get flattened.
*
* @param validator the validator to add
*/
public void addValidator(Validator validator) {
// flatten OrVvalidators
if (validator instanceof OrValidator)
for (Validator childValidator : ((OrValidator) validator).validators)
addValidator(childValidator);
else
validators.add(validator);
}
/**
* @see eu.esdihumboldt.util.validator.Validator#validate(Object)
*/
@Override
public String validate(Object value) {
if (validators.size() == 1) {
return validators.getFirst().validate(value);
}
StringBuilder result = new StringBuilder();
// add results of all validators
for (Validator validator : validators) {
String validation = validator.validate(value);
if (validation != null) {
result.append("\n ").append(validation.replace("\n", "\n "));
}
else
// one validator validates!
return null;
}
if (result.length() > 0)
return "All possibilities are false:" + result.toString();
else
return "Every input is invalid.";
}
/**
* @see eu.esdihumboldt.util.validator.Validator#getDescription()
*/
@Override
public String getDescription() {
// special cases
if (validators.size() == 0)
return "No input is valid.";
if (validators.size() == 1) // also special case isAlwaysTrue()
return validators.getFirst().getDescription();
// default: put together descriptions of known validators
StringBuilder description = new StringBuilder();
description.append("One of the following must be true to be valid:");
for (Validator validator : validators)
description.append("\n ").append(validator.getDescription().replace("\n", "\n "));
return description.toString();
}
/**
* @see eu.esdihumboldt.util.validator.Validator#isAlwaysTrue()
*/
@Override
public boolean isAlwaysTrue() {
for (Validator validator : validators)
if (validator.isAlwaysTrue())
return true;
return false;
}
/**
* @return the internal validators
*/
@Override
public List<Validator> getValidators() {
return Collections.unmodifiableList(validators);
}
}