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[LANG-907] retrieve class hierarchy 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1510298 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Matthew Jason Benson 2013-08-04 18:36:17 +00:00
parent 3fcbc4a4fa
commit eb45c596a8
2 changed files with 133 additions and 1 deletions
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110
src/main/java/org/apache/commons/lang3/ClassUtils.java
View File

@ -19,12 +19,16 @@ package org.apache.commons.lang3;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.lang3.mutable.MutableObject;
/**
* <p>Operates on classes without using reflection.</p>
@ -41,6 +45,12 @@ import java.util.Map;
* @version $Id$
*/
public class ClassUtils {
/**
* @see ClassUtils#hierarchy(Class, Interfaces)
*/
public enum Interfaces {
INCLUDE, EXCLUDE;
}
/**
* The package separator character: <code>'&#x2e;' == {@value}</code>.
@ -1129,4 +1139,102 @@ public class ClassUtils {
}
}
}
/**
* Get an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order,
* excluding interfaces.
*
* @param type
* @return Iterable
*/
public static Iterable<Class<?>> hierarchy(final Class<?> type) {
return hierarchy(type, Interfaces.EXCLUDE);
}
/**
* Get an {@link Iterable} that can iterate over a class hierarchy in ascending (subclass to superclass) order.
*
* @param type
* @param interfacesBehavior
* @return Iterable
*/
public static Iterable<Class<?>> hierarchy(final Class<?> type, Interfaces interfacesBehavior) {
final Iterable<Class<?>> classes = new Iterable<Class<?>>() {
@Override
public Iterator<Class<?>> iterator() {
final MutableObject<Class<?>> next = new MutableObject<Class<?>>(type);
return new Iterator<Class<?>>() {
@Override
public boolean hasNext() {
return next.getValue() != null;
}
@Override
public Class<?> next() {
final Class<?> result = next.getValue();
next.setValue(result.getSuperclass());
return result;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
};
if (interfacesBehavior != Interfaces.INCLUDE) {
return classes;
}
return new Iterable<Class<?>>() {
@Override
public Iterator<Class<?>> iterator() {
final Set<Class<?>> seenInterfaces = new HashSet<Class<?>>();
final Iterator<Class<?>> wrapped = classes.iterator();
return new Iterator<Class<?>>() {
Iterator<Class<?>> interfaces = Collections.<Class<?>> emptySet().iterator();
@Override
public boolean hasNext() {
return interfaces.hasNext() || wrapped.hasNext();
}
@Override
public Class<?> next() {
if (interfaces.hasNext()) {
final Class<?> nextInterface = interfaces.next();
seenInterfaces.add(nextInterface);
return nextInterface;
}
final Class<?> nextSuperclass = wrapped.next();
final Set<Class<?>> currentInterfaces = new LinkedHashSet<Class<?>>();
walkInterfaces(currentInterfaces, nextSuperclass);
interfaces = currentInterfaces.iterator();
return nextSuperclass;
}
private void walkInterfaces(Set<Class<?>> addTo, Class<?> c) {
for (Class<?> iface : c.getInterfaces()) {
if (!seenInterfaces.contains(iface)) {
addTo.add(iface);
}
walkInterfaces(addTo, iface);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
};
}
}

24
src/test/java/org/apache/commons/lang3/ClassUtilsTest.java
View File

@ -34,10 +34,15 @@ import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.lang3.ClassUtils.Interfaces;
import org.apache.commons.lang3.reflect.testbed.GenericConsumer;
import org.apache.commons.lang3.reflect.testbed.GenericParent;
import org.apache.commons.lang3.reflect.testbed.StringParameterizedChild;
import org.junit.Test;
/**
@ -1221,4 +1226,23 @@ public class ClassUtilsTest {
assertEquals("org.apache.commons.lang3", ClassUtils.getPackageCanonicalName("org.apache.commons.lang3.ClassUtilsTest$Inner"));
}
@Test
public void testHierarchyIncludingInterfaces() {
final Iterator<Class<?>> iter =
ClassUtils.hierarchy(StringParameterizedChild.class, Interfaces.INCLUDE).iterator();
assertEquals(StringParameterizedChild.class, iter.next());
assertEquals(GenericParent.class, iter.next());
assertEquals(GenericConsumer.class, iter.next());
assertEquals(Object.class, iter.next());
assertFalse(iter.hasNext());
}
@Test
public void testHierarchyExcludingInterfaces() {
final Iterator<Class<?>> iter = ClassUtils.hierarchy(StringParameterizedChild.class).iterator();
assertEquals(StringParameterizedChild.class, iter.next());
assertEquals(GenericParent.class, iter.next());
assertEquals(Object.class, iter.next());
assertFalse(iter.hasNext());
}
}