1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.apache.giraph.io.gora.utils;
19
20 import org.apache.gora.persistency.Persistent;
21 import org.apache.gora.query.Query;
22 import org.apache.gora.query.Result;
23 import org.apache.gora.query.impl.QueryBase;
24 import org.apache.gora.store.DataStore;
25 import org.apache.gora.store.DataStoreFactory;
26 import org.apache.gora.util.GoraException;
27 import org.apache.hadoop.conf.Configuration;
28
29 /**
30 * Class used to handle the creation and querying of data stores through Gora.
31 */
32 public class GoraUtils {
33
34 /**
35 * Attribute handling the specific class to be created.
36 */
37 private static Class<? extends DataStore> DATASTORECLASS;
38
39 /**
40 * The default constructor is set to be private by default so that the
41 * class is not instantiated.
42 */
43 private GoraUtils() { /* private constructor */ }
44
45 /**
46 * Creates a generic data store using the data store class.
47 * set using the class property
48 * @param conf Configuration
49 * @param <K> key class
50 * @param <T> value class
51 * @param keyClass key class used
52 * @param persistentClass persistent class used
53 * @return created data store
54 * @throws GoraException exception threw
55 */
56 @SuppressWarnings("unchecked")
57 public static <K, T extends Persistent> DataStore<K, T>
58 createDataStore(Configuration conf,
59 Class<K> keyClass, Class<T> persistentClass)
60 throws GoraException {
61 DataStoreFactory.createProps();
62 DataStore<K, T> dataStore =
63 DataStoreFactory.createDataStore((Class<? extends DataStore<K, T>>)
64 DATASTORECLASS,
65 keyClass, persistentClass,
66 conf);
67
68 return dataStore;
69 }
70
71 /**
72 * Creates a specific data store specified by.
73 * @param conf Configuration
74 * @param <K> key class
75 * @param <T> value class
76 * @param dataStoreClass Defines the type of data store used.
77 * @param keyClass Handles the key class to be used.
78 * @param persistentClass Handles the persistent class to be used.
79 * @return DataStore created using parameters passed.
80 * @throws GoraException if an error occurs.
81 */
82 public static <K, T extends Persistent> DataStore<K, T>
83 createSpecificDataStore(Configuration conf,
84 Class<? extends DataStore> dataStoreClass,
85 Class<K> keyClass, Class<T> persistentClass) throws GoraException {
86 DATASTORECLASS = dataStoreClass;
87 return createDataStore(conf, keyClass, persistentClass);
88 }
89
90 /**
91 * Performs a range query to Gora datastores
92 * @param <K> key class
93 * @param <T> value class
94 * @param pDataStore data store being used.
95 * @param pStartKey start key for the range query.
96 * @param pEndKey end key for the range query.
97 * @return Result containing all results for the query.
98 */
99 public static <K, T extends Persistent> Result<K, T>
100 getRequest(DataStore<K, T> pDataStore, K pStartKey, K pEndKey) {
101 QueryBase query = getQuery(pDataStore, pStartKey, pEndKey);
102 return getRequest(pDataStore, query);
103 }
104
105 /**
106 * Performs a query to Gora datastores
107 * @param pDataStore data store being used.
108 * @param query query executed over data stores.
109 * @param <K> key class
110 * @param <T> value class
111 * @return Result containing all results for the query.
112 */
113 public static <K, T extends Persistent> Result<K, T>
114 getRequest(DataStore<K, T> pDataStore, Query<K, T> query) {
115 return pDataStore.execute(query);
116 }
117
118 /**
119 * Performs a range query to Gora datastores
120 * @param <K> key class
121 * @param <T> value class
122 * @param pDataStore data store being used.
123 * @param pStartKey start key for the range query.
124 * @return Result containing all results for the query.
125 */
126 public static <K, T extends Persistent> Result<K, T>
127 getRequest(DataStore<K, T> pDataStore, K pStartKey) {
128 return getRequest(pDataStore, pStartKey, null);
129 }
130
131 /**
132 * Gets a query object to be used as a range query.
133 * @param pDataStore data store used.
134 * @param pStartKey range start key.
135 * @param pEndKey range end key.
136 * @param <K> key class
137 * @param <T> value class
138 * @return range query object.
139 */
140 public static <K, T extends Persistent> QueryBase
141 getQuery(DataStore pDataStore, K pStartKey, K pEndKey) {
142 QueryBase query = (QueryBase) pDataStore.newQuery();
143 query.setStartKey(pStartKey);
144 query.setEndKey(pEndKey);
145 return query;
146 }
147
148 /**
149 * Gets a query object to be used as a simple get.
150 * @param pDataStore data store used.
151 * @param pStartKey range start key.
152 * @param <K> key class
153 * @param <T> value class
154 * @return query object.
155 */
156 public static <K, T extends Persistent> Query<K, T>
157 getQuery(DataStore<K, T> pDataStore, K pStartKey) {
158 Query<K, T> query = pDataStore.newQuery();
159 query.setStartKey(pStartKey);
160 query.setEndKey(null);
161 return query;
162 }
163
164 /**
165 * Gets a query object to be used as a simple get.
166 * @param pDataStore data store used.
167 * @param <K> key class
168 * @param <T> value class
169 * @return query object.
170 */
171 public static <K, T extends Persistent> Query<K, T>
172 getQuery(DataStore<K, T> pDataStore) {
173 Query<K, T> query = pDataStore.newQuery();
174 query.setStartKey(null);
175 query.setEndKey(null);
176 return query;
177 }
178 }