org.onlab.util.Match Maven / Gradle / Ivy
/*
* Copyright 2016-present Open Networking Foundation
*
* 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.onlab.util;
import static com.google.common.base.MoreObjects.toStringHelper;
import java.util.Arrays;
import java.util.Objects;
import java.util.function.Function;
/**
* Utility class for checking matching values.
*
* @param type of value
*/
public final class Match {
public static final Match ANY = new Match<>();
public static final Match NULL = new Match<>(null, false);
public static final Match NOT_NULL = new Match<>(null, true);
private final boolean matchAny;
private final T value;
private final boolean negation;
/**
* Returns a Match that matches any value including null.
* @param match type
* @return new instance
*/
public static Match any() {
return ANY;
}
/**
* Returns a Match that matches null values.
* @param match type
* @return new instance
*/
public static Match ifNull() {
return NULL;
}
/**
* Returns a Match that matches all non-null values.
* @param match type
* @return new instance
*/
public static Match ifNotNull() {
return NOT_NULL;
}
/**
* Returns a Match that only matches the specified value.
* @param value value to match
* @param match type
* @return new instance
*/
public static Match ifValue(T value) {
return new Match<>(value, false);
}
/**
* Returns a Match that matches any value except the specified value.
* @param value value to not match
* @param match type
* @return new instance
*/
public static Match ifNotValue(T value) {
return new Match<>(value, true);
}
private Match() {
matchAny = true;
negation = false;
value = null;
}
private Match(T value, boolean negation) {
matchAny = false;
this.value = value;
this.negation = negation;
}
/**
* Maps this instance to a Match of another type.
* @param mapper transformation function
* @param new match type
* @return new instance
*/
public Match map(Function mapper) {
if (matchAny) {
return any();
} else if (value == null) {
return negation ? ifNotNull() : ifNull();
} else {
return negation ? ifNotValue(mapper.apply(value)) : ifValue(mapper.apply(value));
}
}
/**
* Checks if this instance matches specified value.
* @param other other value
* @return true if matches; false otherwise
*/
public boolean matches(T other) {
if (matchAny) {
return true;
} else if (other == null) {
return negation ? value != null : value == null;
} else {
if (value instanceof byte[]) {
boolean equal = Arrays.equals((byte[]) value, (byte[]) other);
return negation ? !equal : equal;
}
return negation ? !Objects.equals(value, other) : Objects.equals(value, other);
}
}
@Override
public int hashCode() {
return Objects.hash(matchAny, value, negation);
}
@Override
public boolean equals(Object other) {
if (!(other instanceof Match)) {
return false;
}
Match that = (Match) other;
return this.matchAny == that.matchAny &&
Objects.equals(this.value, that.value) &&
this.negation == that.negation;
}
@Override
public String toString() {
return toStringHelper(this)
.add("matchAny", matchAny)
.add("negation", negation)
.add("value", value)
.toString();
}
}