001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.camel.test.blueprint;
018
019 import java.io.File;
020 import java.io.FileInputStream;
021 import java.io.FileNotFoundException;
022 import java.io.IOException;
023 import java.io.InputStream;
024 import java.net.HttpURLConnection;
025 import java.net.MalformedURLException;
026 import java.net.URL;
027 import java.net.URLConnection;
028 import java.util.Enumeration;
029
030 import org.apache.camel.spi.ClassResolver;
031 import org.apache.camel.util.ObjectHelper;
032
033 /**
034 * Helper class for loading resources on the classpath or file system.
035 */
036 public final class ResourceHelper {
037
038 private ResourceHelper() {
039 // utility class
040 }
041
042 /**
043 * Determines whether the URI has a scheme (e.g. file:, classpath: or http:)
044 *
045 * @param uri the URI
046 * @return <tt>true</tt> if the URI starts with a scheme
047 */
048 public static boolean hasScheme(String uri) {
049 if (uri == null) {
050 return false;
051 }
052
053 return uri.startsWith("file:") || uri.startsWith("classpath:") || uri.startsWith("http:");
054 }
055
056 /**
057 * Resolves the mandatory resource.
058 * <p/>
059 * If possible recommended to use {@link #resolveMandatoryResourceAsUrl(org.apache.camel.spi.ClassResolver, String)}
060 *
061 * @param classResolver the class resolver to load the resource from the classpath
062 * @param uri URI of the resource
063 * @return the resource as an {@link InputStream}. Remember to close this stream after usage.
064 * @throws java.io.IOException is thrown if the resource file could not be found or loaded as {@link InputStream}
065 */
066 public static InputStream resolveMandatoryResourceAsInputStream(ClassResolver classResolver, String uri) throws IOException {
067 if (uri.startsWith("file:")) {
068 uri = ObjectHelper.after(uri, "file:");
069 return new FileInputStream(uri);
070 } else if (uri.startsWith("http:")) {
071 URL url = new URL(uri);
072 URLConnection con = url.openConnection();
073 con.setUseCaches(false);
074 try {
075 return con.getInputStream();
076 } catch (IOException e) {
077 // close the http connection to avoid
078 // leaking gaps in case of an exception
079 if (con instanceof HttpURLConnection) {
080 ((HttpURLConnection) con).disconnect();
081 }
082 throw e;
083 }
084 } else if (uri.startsWith("classpath:")) {
085 uri = ObjectHelper.after(uri, "classpath:");
086 }
087
088 // load from classpath by default
089 InputStream is = classResolver.loadResourceAsStream(uri);
090 if (is == null) {
091 throw new FileNotFoundException("Cannot find resource in classpath for URI: " + uri);
092 } else {
093 return is;
094 }
095 }
096
097 /**
098 * Resolves the mandatory resource.
099 *
100 * @param classResolver the class resolver to load the resource from the classpath
101 * @param uri uri of the resource
102 * @return the resource as an {@link InputStream}. Remember to close this stream after usage.
103 * @throws java.io.FileNotFoundException is thrown if the resource file could not be found
104 * @throws java.net.MalformedURLException if the URI is malformed
105 */
106 public static URL resolveMandatoryResourceAsUrl(ClassResolver classResolver, String uri) throws FileNotFoundException, MalformedURLException {
107 if (uri.startsWith("file:")) {
108 // check if file exists first
109 String name = ObjectHelper.after(uri, "file:");
110 File file = new File(name);
111 if (!file.exists()) {
112 throw new FileNotFoundException("File " + file + " not found");
113 }
114 return new URL(uri);
115 } else if (uri.startsWith("http:")) {
116 return new URL(uri);
117 } else if (uri.startsWith("classpath:")) {
118 uri = ObjectHelper.after(uri, "classpath:");
119 }
120
121 // load from classpath by default
122 URL url = classResolver.loadResourceAsURL(uri);
123 if (url == null) {
124 throw new FileNotFoundException("Cannot find resource in classpath for URI: " + uri);
125 } else {
126 return url;
127 }
128 }
129
130 /**
131 * Attempts to load the given resources from the given package name using the thread context
132 * class loader or the class loader used to load this class
133 *
134 * @param packageName the name of the package to load its resources
135 * @return the URLs for the resources or null if it could not be loaded
136 */
137 public static Enumeration<URL> loadResourcesAsURL(String packageName) {
138 Enumeration<URL> url = null;
139
140 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
141 if (contextClassLoader != null) {
142 try {
143 url = contextClassLoader.getResources(packageName);
144 } catch (IOException e) {
145 // ignore
146 }
147 }
148 if (url == null) {
149 try {
150 url = ObjectHelper.class.getClassLoader().getResources(packageName);
151 } catch (IOException e) {
152 // ignore
153 }
154 }
155
156 return url;
157 }
158
159 }