001 /*
002 * Copyright 2008-2015 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016 package griffon.util;
017
018 import org.slf4j.Logger;
019 import org.slf4j.LoggerFactory;
020
021 import javax.annotation.Nonnull;
022 import java.io.File;
023 import java.io.IOException;
024 import java.net.URISyntaxException;
025 import java.net.URL;
026 import java.util.Enumeration;
027 import java.util.Scanner;
028 import java.util.jar.JarEntry;
029 import java.util.jar.JarFile;
030
031 import static griffon.core.GriffonExceptionHandler.sanitize;
032 import static griffon.util.GriffonNameUtils.isBlank;
033 import static griffon.util.GriffonNameUtils.requireNonBlank;
034 import static java.util.Objects.requireNonNull;
035
036 /**
037 * @author Andres Almiray
038 * @since 2.0.0
039 */
040 public class ServiceLoaderUtils {
041 private static final Logger LOG = LoggerFactory.getLogger(ServiceLoaderUtils.class);
042 private static final String JAR_FILE_SCHEME = "jar:file:";
043
044 private ServiceLoaderUtils() {
045
046 }
047
048 public static boolean load(@Nonnull ClassLoader classLoader, @Nonnull String path, @Nonnull Class<?> type, @Nonnull LineProcessor processor) {
049 requireNonNull(classLoader, "Argument 'classLoader' must not be null");
050 requireNonBlank(path, "Argument 'path' must not be blank");
051 requireNonNull(type, "Argument 'type' must not be null");
052 requireNonNull(processor, "Argument 'processor' must not be null");
053 // "The name of a resource is a /-separated path name that identifies the resource."
054 String normalizedPath = path.endsWith("/") ? path : path + "/";
055
056 Enumeration<URL> urls;
057
058 try {
059 urls = classLoader.getResources(normalizedPath + type.getName());
060 } catch (IOException ioe) {
061 LOG.error(ioe.getClass().getName() + " error loading resources of type \"" + type.getName() + "\" from \"" + normalizedPath + "\".");
062 return false;
063 }
064
065 if (urls == null) return false;
066
067 while (urls.hasMoreElements()) {
068 URL url = urls.nextElement();
069 LOG.debug("Reading {} definitions from {}", type.getName(), url);
070
071 try (Scanner scanner = new Scanner(url.openStream())) {
072 while (scanner.hasNextLine()) {
073 String line = scanner.nextLine();
074 if (line.startsWith("#") || isBlank(line)) continue;
075 processor.process(classLoader, type, line);
076 }
077 } catch (IOException e) {
078 LOG.warn("Could not load " + type.getName() + " definitions from " + url, sanitize(e));
079 }
080 }
081
082 return true;
083 }
084
085 public static boolean load(@Nonnull ClassLoader classLoader, @Nonnull String path, @Nonnull PathFilter pathFilter, @Nonnull ResourceProcessor processor) {
086 requireNonNull(classLoader, "Argument 'classLoader' must not be null");
087 requireNonBlank(path, "Argument 'path' must not be blank");
088 requireNonNull(pathFilter, "Argument 'pathFilter' must not be blank");
089 requireNonNull(processor, "Argument 'processor' must not be null");
090
091 Enumeration<URL> urls;
092
093 try {
094 urls = classLoader.getResources(path);
095 } catch (IOException ioe) {
096 LOG.debug(ioe.getClass().getName() + " error loading resources from \"" + path + "\".");
097 return false;
098 }
099
100 if (urls == null) return false;
101
102 while (urls.hasMoreElements()) {
103 URL url = urls.nextElement();
104 LOG.debug("Reading definitions from " + url);
105 switch (url.getProtocol()) {
106 case "file":
107 handleFileResource(url, classLoader, path, pathFilter, processor);
108 break;
109 case "jar":
110 handleJarResource(url, classLoader, path, pathFilter, processor);
111 break;
112 default:
113 LOG.warn("Could not load definitions from " + url);
114 }
115 }
116
117 return true;
118 }
119
120 private static void handleFileResource(@Nonnull URL url, @Nonnull ClassLoader classLoader, @Nonnull String path, @Nonnull PathFilter pathFilter, @Nonnull ResourceProcessor processor) {
121 try {
122 File file = new File(url.toURI());
123 for (File entry : file.listFiles()) {
124 if (pathFilter.accept(entry.getName())) {
125 try (Scanner scanner = new Scanner(entry)) {
126 while (scanner.hasNextLine()) {
127 String line = scanner.nextLine();
128 if (line.startsWith("#") || isBlank(line)) continue;
129 processor.process(classLoader, line);
130 }
131 } catch (IOException e) {
132 LOG.warn("An error occurred while loading resources from " + entry.getAbsolutePath(), sanitize(e));
133 }
134 }
135 }
136 } catch (URISyntaxException e) {
137 LOG.warn("An error occurred while loading resources from " + url, sanitize(e));
138 }
139 }
140
141 private static void handleJarResource(@Nonnull URL url, @Nonnull ClassLoader classLoader, @Nonnull String path, @Nonnull PathFilter pathFilter, @Nonnull ResourceProcessor processor) {
142 try {
143 String u = url.toString();
144 JarFile jar = new JarFile(u.substring(JAR_FILE_SCHEME.length(), u.length() - path.length() - 2));
145 Enumeration<JarEntry> entries = jar.entries();
146 while (entries.hasMoreElements()) {
147 JarEntry jarEntry = entries.nextElement();
148 if (jarEntry.getName().startsWith(path) && pathFilter.accept(jarEntry.getName())) {
149 try (Scanner scanner = new Scanner(jar.getInputStream(jarEntry))) {
150 while (scanner.hasNextLine()) {
151 String line = scanner.nextLine();
152 if (line.startsWith("#") || isBlank(line)) continue;
153 processor.process(classLoader, line);
154 }
155 } catch (IOException e) {
156 LOG.warn("An error occurred while loading resources from " + jarEntry.getName(), sanitize(e));
157 }
158 }
159 }
160 } catch (IOException e) {
161 LOG.warn("An error occurred while loading resources from " + url, sanitize(e));
162 }
163 }
164
165 public static interface PathFilter {
166 boolean accept(@Nonnull String path);
167 }
168
169 public static interface LineProcessor {
170 void process(@Nonnull ClassLoader classLoader, @Nonnull Class<?> type, @Nonnull String line);
171 }
172
173 public static interface ResourceProcessor {
174 void process(@Nonnull ClassLoader classLoader, @Nonnull String line);
175 }
176 }
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