1 package org.apache.maven.shared.utils.testhelpers;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22
23 import org.hamcrest.BaseMatcher;
24 import org.hamcrest.Description;
25 import org.hamcrest.Matcher;
26
27
28 public class ExceptionHelper
29 {
30
31 /**
32 * A matcher that verifies that the a root cause of an exception is of the specified type.
33 *
34 * @param cause the type of exception that caused this.
35 * @return A matcher that verifies that the a root cause of an exception is of the specified type.
36 */
37 public static Matcher<Throwable> hasCause( Class<? extends Throwable> cause )
38 {
39 return new HasCause( cause );
40 }
41
42 private static class HasCause
43 extends BaseMatcher<Throwable>
44 {
45 private final Class<? extends Throwable> cause;
46
47 public HasCause( Class<? extends Throwable> cause )
48 {
49 this.cause = cause;
50 }
51
52 public boolean matches( Object item )
53 {
54 Throwable throwable = (Throwable) item;
55 while ( throwable != null && !cause.isInstance( throwable ) )
56 {
57 throwable = throwable.getCause();
58 }
59 return cause.isInstance( throwable );
60 }
61
62 public void describeTo( Description description )
63 {
64 description.appendText( "was caused by a " ).appendValue( cause ).appendText( " being thrown" );
65 }
66 }
67 }