[15416] | 1 | // License: GPL. For details, see LICENSE file.
|
---|
| 2 | package org.openstreetmap.josm.tools;
|
---|
| 3 |
|
---|
| 4 | import java.io.InputStream;
|
---|
| 5 | import java.net.URL;
|
---|
| 6 | import java.util.Collection;
|
---|
| 7 | import java.util.Collections;
|
---|
| 8 | import java.util.HashSet;
|
---|
| 9 | import java.util.Set;
|
---|
| 10 | import java.util.function.Function;
|
---|
| 11 |
|
---|
| 12 | /**
|
---|
| 13 | * Unified provider that looks up for resource in various classloaders (josm, plugins, etc.).
|
---|
| 14 | * @since 15416
|
---|
| 15 | */
|
---|
| 16 | public final class ResourceProvider {
|
---|
| 17 |
|
---|
| 18 | /** set of class loaders to take resources from */
|
---|
| 19 | private static final Set<ClassLoader> classLoaders = Collections.synchronizedSet(new HashSet<>());
|
---|
| 20 | static {
|
---|
| 21 | try {
|
---|
| 22 | classLoaders.add(ClassLoader.getSystemClassLoader());
|
---|
| 23 | } catch (SecurityException e) {
|
---|
| 24 | Logging.log(Logging.LEVEL_ERROR, "Unable to get system classloader", e);
|
---|
| 25 | }
|
---|
| 26 | try {
|
---|
| 27 | classLoaders.add(ResourceProvider.class.getClassLoader());
|
---|
| 28 | } catch (SecurityException e) {
|
---|
| 29 | Logging.log(Logging.LEVEL_ERROR, "Unable to get application classloader", e);
|
---|
| 30 | }
|
---|
| 31 | }
|
---|
| 32 |
|
---|
| 33 | private ResourceProvider() {
|
---|
| 34 | // Hide default constructor for utilities classes
|
---|
| 35 | }
|
---|
| 36 |
|
---|
| 37 | /**
|
---|
| 38 | * Add an additional class loader to search image for.
|
---|
| 39 | * @param additionalClassLoader class loader to add to the internal set
|
---|
| 40 | * @return {@code true} if the set changed as a result of the call
|
---|
| 41 | */
|
---|
| 42 | public static boolean addAdditionalClassLoader(ClassLoader additionalClassLoader) {
|
---|
| 43 | return classLoaders.add(additionalClassLoader);
|
---|
| 44 | }
|
---|
| 45 |
|
---|
| 46 | /**
|
---|
| 47 | * Add a collection of additional class loaders to search image for.
|
---|
| 48 | * @param additionalClassLoaders class loaders to add to the internal set
|
---|
| 49 | * @return {@code true} if the set changed as a result of the call
|
---|
| 50 | */
|
---|
| 51 | public static boolean addAdditionalClassLoaders(Collection<ClassLoader> additionalClassLoaders) {
|
---|
| 52 | return classLoaders.addAll(additionalClassLoaders);
|
---|
| 53 | }
|
---|
| 54 |
|
---|
| 55 | private static <T> T getFirstNotNull(Function<ClassLoader, T> function) {
|
---|
| 56 | synchronized (classLoaders) {
|
---|
| 57 | for (ClassLoader source : classLoaders) {
|
---|
| 58 | T res = function.apply(source);
|
---|
| 59 | if (res != null)
|
---|
| 60 | return res;
|
---|
| 61 | }
|
---|
| 62 | }
|
---|
| 63 | return null;
|
---|
| 64 | }
|
---|
| 65 |
|
---|
| 66 | /**
|
---|
| 67 | * Finds the resource with the given name.
|
---|
| 68 | * @param name The resource name
|
---|
| 69 | * @return A {@code URL} object for reading the resource, or {@code null} if the resource could not be found
|
---|
| 70 | * or the invoker doesn't have adequate privileges to get the resource.
|
---|
| 71 | * @see ClassLoader#getResource
|
---|
| 72 | */
|
---|
| 73 | public static URL getResource(String name) {
|
---|
| 74 | return getFirstNotNull(x -> x.getResource(name));
|
---|
| 75 | }
|
---|
| 76 |
|
---|
| 77 | /**
|
---|
| 78 | * Finds a resource with a given name, with robustness to known JDK bugs.
|
---|
| 79 | * @param name name of the desired resource
|
---|
| 80 | * @return A {@link java.io.InputStream} object or {@code null} if no resource with this name is found
|
---|
| 81 | */
|
---|
| 82 | public static InputStream getResourceAsStream(String name) {
|
---|
| 83 | return getFirstNotNull(x -> Utils.getResourceAsStream(x, name));
|
---|
| 84 | }
|
---|
| 85 | }
|
---|