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LANG-863 Method returns number of inheritance hops between parent and subclass 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1545145 13f79535-47bb-0310-9956-ffa450edef68
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Sebastian Bazley 2013-11-25 03:38:11 +00:00
parent 7c919293f7
commit cfb488a05f
6 changed files with 209 additions and 0 deletions
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1
src/changes/changes.xml
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<body>
<release version="3.2" date="TBA" description="Next release">
<action issue="LANG-863" type="add" due-to="Daneel S. Yaitskov" dev="sebb">Method returns number of inheritance hops between parent and subclass</action>
<action issue="LANG-932" type="fix" due-to="Ville Skyttä" dev="sebb">Spelling fixes</action>
<action issue="LANG-931" type="update" dev="britter" due-to="Christoph Schneegans">Misleading Javadoc comment in StrBuilderReader class</action>
<action issue="LANG-929" type="fix">OctalUnescaper tried to parse all of \279</action>

60
src/main/java/org/apache/commons/lang3/reflect/InheritanceUtils.java Normal file
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.reflect;
import org.apache.commons.lang3.BooleanUtils;
/**
* <p>Utility methods focusing on inheritance.</p>
*
* @since 3.2
*/
public class InheritanceUtils {
public InheritanceUtils() {
super();
}
/**
* <p>Returns the number of inheritance hops between two classes.</p>
*
* @param child the child class, may be {@code null}
* @param parent the parent class, may be {@code null}
* @return the number of generations between the child and parent; 0 if the same class;
* -1 if the classes are not related as child and parent (includes where either class is null)
* @since 3.2
*/
public static int distance(final Class<?> child, final Class<?> parent) {
if (child == null || parent == null) {
return -1;
}
if (child.equals(parent)) {
return 0;
}
final Class<?> cParent = child.getSuperclass();
int d = BooleanUtils.toInteger(parent.equals(cParent));
if (d == 1) {
return d;
} else {
d += distance(cParent, parent);
return d > 0 ? d + 1 : -1;
}
}
}

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src/test/java/org/apache/commons/lang3/reflect/InheritanceUtilsTest.java Normal file
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.reflect;
import org.apache.commons.lang3.reflect.testbed.AnotherChild;
import org.apache.commons.lang3.reflect.testbed.AnotherParent;
import org.apache.commons.lang3.reflect.testbed.Grandchild;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
/**
* Unit tests InheritanceUtils
*/
public class InheritanceUtilsTest {
@Test
public void testConstructor() throws Exception {
assertNotNull(InheritanceUtils.class.newInstance());
}
@Test
public void testDistanceGreaterThanZero() {
assertEquals(1, InheritanceUtils.distance(AnotherChild.class, AnotherParent.class));
assertEquals(1, InheritanceUtils.distance(Grandchild.class, AnotherChild.class));
assertEquals(2, InheritanceUtils.distance(Grandchild.class, AnotherParent.class));
assertEquals(3, InheritanceUtils.distance(Grandchild.class, Object.class));
}
@Test
public void testDistanceEqual() {
assertEquals(0, InheritanceUtils.distance(AnotherChild.class, AnotherChild.class));
}
@Test
public void testDistanceEqualObject() {
assertEquals(0, InheritanceUtils.distance(Object.class, Object.class));
}
@Test
public void testDistanceNullChild() {
assertEquals(-1, InheritanceUtils.distance(null, Object.class));
}
@Test
public void testDistanceNullParent() {
assertEquals(-1, InheritanceUtils.distance(Object.class, null));
}
@Test
public void testDistanceNullParentNullChild() {
assertEquals(-1, InheritanceUtils.distance(null, null));
}
@Test
public void testDistanceDisjoint() {
assertEquals(-1, InheritanceUtils.distance(Boolean.class, String.class));
}
@Test
public void testDistanceReverseParentChild() {
assertEquals(-1, InheritanceUtils.distance(Object.class, Grandchild.class));
}
}

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src/test/java/org/apache/commons/lang3/reflect/testbed/AnotherChild.java Normal file
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.reflect.testbed;
/**
*
*/
public class AnotherChild extends AnotherParent {
}

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src/test/java/org/apache/commons/lang3/reflect/testbed/AnotherParent.java Normal file
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.reflect.testbed;
/**
*
*/
public class AnotherParent {
}

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src/test/java/org/apache/commons/lang3/reflect/testbed/Grandchild.java Normal file
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.reflect.testbed;
/**
*
*/
public class Grandchild extends AnotherChild {
}