1 /*
2 * #%L
3 * settings4j
4 * ===============================================================
5 * Copyright (C) 2008 - 2015 Brabenetz Harald, Austria
6 * ===============================================================
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * #L%
19 */
20 package org.settings4j.contentresolver;
21
22 import org.apache.commons.lang3.Validate;
23 import org.settings4j.ContentResolver;
24 import org.settings4j.Filter;
25
26 /**
27 * Wrapper to add a {@link Filter} which is used before the given {@link ContentResolver} is called.
28 *
29 * @author Harald.Brabenetz
30 *
31 */
32 public class FilteredContentResolverWrapper implements ContentResolver {
33
34 private final ContentResolver targetContentResolver;
35 private final Filter filter;
36
37 /**
38 * @param targetContentResolver The {@link ContentResolver} where the settings
39 * should be read if the Filter allows it.
40 * @param filter the {@link Filter} which defines if an key should be read from the given {@link ContentResolver}.
41 */
42 public FilteredContentResolverWrapper(final ContentResolver targetContentResolver, final Filter filter) {
43 super();
44 Validate.notNull(targetContentResolver, "FilteredContentResolverWrapper needs a ContentResolver Object");
45 Validate.notNull(filter, "FilteredContentResolverWrapper needs a Filter Object");
46 this.targetContentResolver = targetContentResolver;
47 this.filter = filter;
48 }
49
50 @Override
51 public void addContentResolver(final ContentResolver contentResolver) {
52 this.targetContentResolver.addContentResolver(contentResolver);
53 }
54
55 @Override
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 }