1 /* 2 * Copyright 2016 The gRPC Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 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 17 package io.grpc; 18 19 import java.io.IOException; 20 import java.net.URL; 21 import java.util.Enumeration; 22 23 /** 24 * A ClassLoader to help test service providers. 25 */ 26 public class ReplacingClassLoader extends ClassLoader { 27 private final String resource; 28 private final String replacement; 29 30 /** 31 * Construct an instance where {@code replacement} is loaded instead of {@code resource}. 32 */ ReplacingClassLoader(ClassLoader parent, String resource, String replacement)33 public ReplacingClassLoader(ClassLoader parent, String resource, String replacement) { 34 super(parent); 35 this.resource = resource; 36 this.replacement = replacement; 37 } 38 39 @Override getResource(String name)40 public URL getResource(String name) { 41 if (resource.equals(name)) { 42 return getParent().getResource(replacement); 43 } 44 return super.getResource(name); 45 } 46 47 @Override getResources(String name)48 public Enumeration<URL> getResources(String name) throws IOException { 49 if (resource.equals(name)) { 50 return getParent().getResources(replacement); 51 } 52 return super.getResources(name); 53 } 54 } 55 56