org.databene.commons.validator.UniqueValidator Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of databene-commons Show documentation
Show all versions of databene-commons Show documentation
'databene commons' is an open source Java library by Volker Bergmann.
It provides extensions to the Java core library by utility classes, abstract concepts
and concrete implementations.
/*
* Copyright (C) 2004-2014 Volker Bergmann ([email protected]).
* All rights reserved.
*
* 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.databene.commons.validator;
import org.databene.commons.Resettable;
import org.databene.commons.Validator;
import java.util.Set;
import java.util.HashSet;
/**
* Validator implementation that requires each argument
* of consecutive calls to the valid() method to be unique.
*
* Created: 20.11.2007 09:55:16
* @author Volker Bergmann
*/
public class UniqueValidator implements Validator, Resettable {
private Set instances = new HashSet();
@Override
public boolean valid(E object) {
if (instances.contains(object))
return false;
instances.add(object);
return true;
}
@Override
public void reset() {
instances.clear();
}
@Override
public String toString() {
return getClass().getSimpleName();
}
}