001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.fusesource.hawtdb.api; 018 019 import java.io.IOException; 020 import java.util.Iterator; 021 import java.util.Map; 022 023 /** 024 * Provides Key/Value storage and retrieval. 025 * 026 * @author <a href="http://hiramchirino.com">Hiram Chirino</a> 027 */ 028 public interface Index<Key,Value> { 029 030 /** 031 * Frees any extra storage that the index created. 032 */ 033 void destroy(); 034 035 /** 036 * clear the index 037 * 038 * @throws IOException 039 * 040 */ 041 void clear(); 042 043 /** 044 * @param key 045 * @return true if it contains the key 046 * @throws IOException 047 */ 048 boolean containsKey(Key key); 049 050 /** 051 * remove the index key 052 * 053 * @param key 054 * @return StoreEntry removed 055 * @throws IOException 056 */ 057 Value remove(Key key); 058 059 /** 060 * store the key, item 061 * 062 * @param key 063 * @param entry 064 * @throws IOException 065 */ 066 Value put(Key key, Value entry); 067 068 /** 069 * get the value at the given key, or put it if null. 070 * 071 * @param key 072 * @param entry 073 * @throws IOException 074 */ 075 Value putIfAbsent(Key key, Value entry); 076 077 /** 078 * @param key 079 * @return the entry 080 * @throws IOException 081 */ 082 Value get(Key key); 083 084 int size(); 085 086 boolean isEmpty(); 087 088 /** 089 * @return the location where index root resides on the page file. 090 */ 091 int getIndexLocation(); 092 093 }