| /* |
| * Copyright 2010 Roger Kapsi |
| * |
| * 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.apache.cassandra.index.sasi.utils.trie; |
| |
| import java.util.Comparator; |
| |
| /** |
| * This class is taken from https://github.com/rkapsi/patricia-trie (v0.6), and slightly modified |
| * to correspond to Cassandra code style, as the only Patricia Trie implementation, |
| * which supports pluggable key comparators (e.g. commons-collections PatriciaTrie (which is based |
| * on rkapsi/patricia-trie project) only supports String keys) |
| * but unfortunately is not deployed to the maven central as a downloadable artifact. |
| */ |
| |
| /** |
| * The {@link KeyAnalyzer} provides bit-level access to keys |
| * for the {@link PatriciaTrie}. |
| */ |
| public interface KeyAnalyzer<K> extends Comparator<K> |
| { |
| /** |
| * Returned by {@link #bitIndex(Object, Object)} if a key's |
| * bits were all zero (0). |
| */ |
| int NULL_BIT_KEY = -1; |
| |
| /** |
| * Returned by {@link #bitIndex(Object, Object)} if a the |
| * bits of two keys were all equal. |
| */ |
| int EQUAL_BIT_KEY = -2; |
| |
| /** |
| * Returned by {@link #bitIndex(Object, Object)} if a keys |
| * indices are out of bounds. |
| */ |
| int OUT_OF_BOUNDS_BIT_KEY = -3; |
| |
| /** |
| * Returns the key's length in bits. |
| */ |
| int lengthInBits(K key); |
| |
| /** |
| * Returns {@code true} if a key's bit it set at the given index. |
| */ |
| boolean isBitSet(K key, int bitIndex); |
| |
| /** |
| * Returns the index of the first bit that is different in the two keys. |
| */ |
| int bitIndex(K key, K otherKey); |
| |
| /** |
| * Returns {@code true} if the second argument is a |
| * prefix of the first argument. |
| */ |
| boolean isPrefix(K key, K prefix); |
| } |