01 /*
02 * Copyright 2008-2014 the original author or authors.
03 *
04 * Licensed under the Apache License, Version 2.0 (the "License");
05 * you may not use this file except in compliance with the License.
06 * You may obtain a copy of the License at
07 *
08 * http://www.apache.org/licenses/LICENSE-2.0
09 *
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 package griffon.util;
17
18 import org.slf4j.Logger;
19 import org.slf4j.LoggerFactory;
20
21 import javax.annotation.Nonnull;
22 import java.io.File;
23 import java.io.IOException;
24 import java.net.URL;
25 import java.util.Enumeration;
26 import java.util.Scanner;
27
28 import static griffon.core.GriffonExceptionHandler.sanitize;
29 import static griffon.util.GriffonNameUtils.isBlank;
30 import static griffon.util.GriffonNameUtils.requireNonBlank;
31 import static java.util.Objects.requireNonNull;
32
33 /**
34 * @author Andres Almiray
35 * @since 2.0.0
36 */
37 public class ServiceLoaderUtils {
38 private static final Logger LOG = LoggerFactory.getLogger(ServiceLoaderUtils.class);
39
40 private ServiceLoaderUtils() {
41
42 }
43
44 public static interface LineProcessor {
45 void process(@Nonnull ClassLoader classLoader, @Nonnull Class<?> type, @Nonnull String line);
46 }
47
48 public static boolean load(@Nonnull ClassLoader classLoader, @Nonnull String path, @Nonnull Class<?> type, @Nonnull LineProcessor processor) {
49 requireNonNull(classLoader, "Argument 'classLoader' must not be null");
50 requireNonBlank(path, "Argument 'path' must not be blank");
51 requireNonNull(type, "Argument 'type' must not be null");
52 requireNonNull(processor, "Argument 'processor' must not be null");
53 String normalizedPath = path.endsWith(File.separator) ? path : path + File.separator;
54
55 Enumeration<URL> urls;
56
57 try {
58 urls = classLoader.getResources(normalizedPath + type.getName());
59 } catch (IOException ioe) {
60 return false;
61 }
62
63 if (urls == null) return false;
64
65 while (urls.hasMoreElements()) {
66 URL url = urls.nextElement();
67 LOG.debug("Reading {} definitions from {}", type.getName(), url);
68
69 try (Scanner scanner = new Scanner(url.openStream())) {
70 while (scanner.hasNextLine()) {
71 String line = scanner.nextLine();
72 if (line.startsWith("#") || isBlank(line)) continue;
73 processor.process(classLoader, type, line);
74 }
75 } catch (IOException e) {
76 LOG.warn("Could not load " + type.getName() + " definitions from " + url, sanitize(e));
77 }
78 }
79
80 return true;
81 }
82 }
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