001 /* Copyright (c) 2000-2006 hamcrest.org
002 */
003 package org.hamcrest.core;
004
005 import org.hamcrest.Description;
006 import org.hamcrest.DiagnosingMatcher;
007 import org.hamcrest.Factory;
008 import org.hamcrest.Matcher;
009
010
011 /**
012 * Tests whether the value is an instance of a class.
013 * Classes of basic types will be converted to the relevant "Object" classes
014 */
015 public class IsInstanceOf extends DiagnosingMatcher<Object> {
016 private final Class<?> expectedClass;
017 private final Class<?> matchableClass;
018
019 /**
020 * Creates a new instance of IsInstanceOf
021 *
022 * @param expectedClass The predicate evaluates to true for instances of this class
023 * or one of its subclasses.
024 */
025 public IsInstanceOf(Class<?> expectedClass) {
026 this.expectedClass = expectedClass;
027 this.matchableClass = matchableClass(expectedClass);
028 }
029
030 private static Class<?> matchableClass(Class<?> expectedClass) {
031 if (boolean.class.equals(expectedClass)) return Boolean.class;
032 if (byte.class.equals(expectedClass)) return Byte.class;
033 if (char.class.equals(expectedClass)) return Character.class;
034 if (double.class.equals(expectedClass)) return Double.class;
035 if (float.class.equals(expectedClass)) return Float.class;
036 if (int.class.equals(expectedClass)) return Integer.class;
037 if (long.class.equals(expectedClass)) return Long.class;
038 if (short.class.equals(expectedClass)) return Short.class;
039 return expectedClass;
040 }
041
042 @Override
043 protected boolean matches(Object item, Description mismatch) {
044 if (null == item) {
045 mismatch.appendText("null");
046 return false;
047 }
048
049 if (!matchableClass.isInstance(item)) {
050 mismatch.appendValue(item).appendText(" is a " + item.getClass().getName());
051 return false;
052 }
053
054 return true;
055 }
056
057 @Override
058 public void describeTo(Description description) {
059 description.appendText("an instance of ").appendText(expectedClass.getName());
060 }
061
062 /**
063 * Creates a matcher that matches when the examined object is an instance of the specified <code>type</code>,
064 * as determined by calling the {@link java.lang.Class#isInstance(Object)} method on that type, passing the
065 * the examined object.
066 *
067 * <p>The created matcher assumes no relationship between specified type and the examined object.</p>
068 * <p/>
069 * For example:
070 * <pre>assertThat(new Canoe(), instanceOf(Paddlable.class));</pre>
071 *
072 */
073 @SuppressWarnings("unchecked")
074 @Factory
075 public static <T> Matcher<T> instanceOf(Class<?> type) {
076 return (Matcher<T>) new IsInstanceOf(type);
077 }
078
079 /**
080 * Creates a matcher that matches when the examined object is an instance of the specified <code>type</code>,
081 * as determined by calling the {@link java.lang.Class#isInstance(Object)} method on that type, passing the
082 * the examined object.
083 *
084 * <p>The created matcher forces a relationship between specified type and the examined object, and should be
085 * used when it is necessary to make generics conform, for example in the JMock clause
086 * <code>with(any(Thing.class))</code></p>
087 * <p/>
088 * For example:
089 * <pre>assertThat(new Canoe(), instanceOf(Canoe.class));</pre>
090 *
091 */
092 @SuppressWarnings("unchecked")
093 @Factory
094 public static <T> Matcher<T> any(Class<T> type) {
095 return (Matcher<T>) new IsInstanceOf(type);
096 }
097
098 }