| /* |
| * 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 <T> type of value |
| */ |
| public final class Match<T> { |
| |
| 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 <T> match type |
| * @return new instance |
| */ |
| public static <T> Match<T> any() { |
| return ANY; |
| } |
| |
| /** |
| * Returns a Match that matches null values. |
| * @param <T> match type |
| * @return new instance |
| */ |
| public static <T> Match<T> ifNull() { |
| return NULL; |
| } |
| |
| /** |
| * Returns a Match that matches all non-null values. |
| * @param <T> match type |
| * @return new instance |
| */ |
| public static <T> Match<T> ifNotNull() { |
| return NOT_NULL; |
| } |
| |
| /** |
| * Returns a Match that only matches the specified value. |
| * @param value value to match |
| * @param <T> match type |
| * @return new instance |
| */ |
| public static <T> Match<T> 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 <T> match type |
| * @return new instance |
| */ |
| public static <T> Match<T> 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 <V> new match type |
| * @return new instance |
| */ |
| public <V> Match<V> map(Function<T, V> 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<T> that = (Match<T>) 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(); |
| } |
| } |