io.timeandspace.collect.StatelessEquivalence Maven / Gradle / Ivy
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/*
* Copyright (C) The SmoothieMap 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 io.timeandspace.collect;
/**
* Base class for stateless {@link Equivalence} implementations.
*
* {@code StatelessEquivalence} relies on the fact that your equivalence class,
* which extend it, don't have subclasses in turn, therefore it is strongly recommended to declare
* your equivalence class as {@code final}.
*
*
Override {@link #toString()} if implementation is anonymous and you want to log
* or pretty print it, because otherwise {@code String} representation of your equivalence
* would be {@code ""} (empty {@code String}).
*
*
See example implementations in the documentation to {@linkplain #identity() identity} and
* {@linkplain #caseInsensitive() case insensitive} equivalences.
*/
public abstract class StatelessEquivalence extends Equivalence {
/**
* Constructor for use by subclasses.
*/
protected StatelessEquivalence() {
super();
}
/**
* Returns {@code true} if the given object is also an instance of this equivalence class.
*
* @return if the given object is also an instance of this equivalence class
*/
@Override
public boolean equals(Object o) {
return o != null && o.getClass() == getClass();
}
/**
* Returns a hash code of this equivalence class.
*
* @return a hash code of this equivalence class
*/
@Override
public int hashCode() {
return getClass().hashCode();
}
/**
* Returns simple name of this equivalence class, {@code getClass().getSimpleName()}.
*
* @return simple name of this equivalence class
*/
@Override
public String toString() {
return getClass().getSimpleName();
}
}