1 /* ***************************************************************************
2 * Copyright (c) 2008 Brabenetz Harald, Austria.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *
16 *****************************************************************************/
17 package org.settings4j.contentresolver;
18
19 import org.settings4j.ContentResolver;
20 import org.settings4j.Filter;
21
22 /**
23 * Wrapper to add a {@link Filter} which is used before the given {@link ContentResolver} is called.
24 *
25 * @author Harald.Brabenetz
26 *
27 */
28 public class FilteredContentResolverWrapper implements ContentResolver {
29
30 private final ContentResolver targetContentResolver;
31 private final Filter filter;
32
33 /**
34 * @param targetContentResolver The {@link ContentResolver} where the settings
35 * should be read if the Filter allows it.
36 * @param filter the {@link Filter} which defines if an key should be read from the given {@link ContentResolver}.
37 */
38 public FilteredContentResolverWrapper(final ContentResolver targetContentResolver, final Filter filter) {
39 super();
40 if (targetContentResolver == null) {
41 throw new IllegalArgumentException("FilteredConnectorWrapper needs a ContentResolver Object");
42 }
43 if (filter == null) {
44 throw new IllegalArgumentException("FilteredConnectorWrapper needs a Filter Object");
45 }
46 this.targetContentResolver = targetContentResolver;
47 this.filter = filter;
48 }
49
50 /** {@inheritDoc} */
51 public void addContentResolver(final ContentResolver contentResolver) {
52 this.targetContentResolver.addContentResolver(contentResolver);
53 }
54
55 /** {@inheritDoc} */
56 public byte[] getContent(final String key) {
57 if (!this.filter.isValid(key)) {
58 return null;
59 }
60 return this.targetContentResolver.getContent(key);
61 }
62 }