Add methods for Cloneables to ObjectUtils (LANG-576).
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@908745 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/commons/lang3/ObjectUtils.java b/src/main/java/org/apache/commons/lang3/ObjectUtils.java
index fdfc468..e2b2cf0 100644
--- a/src/main/java/org/apache/commons/lang3/ObjectUtils.java
+++ b/src/main/java/org/apache/commons/lang3/ObjectUtils.java
@@ -17,6 +17,10 @@
package org.apache.commons.lang3;
import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+import org.apache.commons.lang3.exception.CloneFailedException;
/**
* <p>Operations on <code>Object</code>.</p>
@@ -309,6 +313,48 @@
return c1 != null ? c1 : c2;
}
}
+
+ /**
+ * Clone an object.
+ *
+ * @param <T> the type of the object
+ * @param o the object to clone
+ * @return the clone if the object implements {@link Cloneable} otherwise <code>null</code>
+ * @throws CloneFailedException if the object is cloneable and the clone operation fails
+ * @since 3.0
+ */
+ public static <T> T clone(final T o) {
+ if (o instanceof Cloneable) {
+ try {
+ final Method clone = o.getClass().getMethod("clone", (Class[])null);
+ @SuppressWarnings("unchecked")
+ final T result = (T)clone.invoke(o, (Object[])null);
+ return result;
+ } catch (final NoSuchMethodException e) {
+ throw new CloneFailedException("Cloneable type has no clone method", e);
+ } catch (final IllegalAccessException e) {
+ throw new CloneFailedException("Cannot clone Cloneable type", e);
+ } catch (final InvocationTargetException e) {
+ throw new CloneFailedException("Exception cloning Cloneable type", e.getCause());
+ }
+ }
+
+ return null;
+ }
+
+ /**
+ * Clone an object if possible.
+ *
+ * @param <T> the type of the object
+ * @param o the object to clone
+ * @return the clone if the object implements {@link Cloneable} otherwise the object itself
+ * @throws CloneFailedException if the object is cloneable and the clone operation fails
+ * @since 3.0
+ */
+ public static <T> T cloneIfPossible(final T o) {
+ final T clone = clone(o);
+ return clone == null ? o : clone;
+ }
// Null
//-----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/lang3/exception/CloneFailedException.java b/src/main/java/org/apache/commons/lang3/exception/CloneFailedException.java
new file mode 100644
index 0000000..7bef6dd
--- /dev/null
+++ b/src/main/java/org/apache/commons/lang3/exception/CloneFailedException.java
@@ -0,0 +1,63 @@
+/*
+ * 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.exception;
+
+/**
+ * Exception thrown when a clone cannot be created. In contrast to
+ * {@link CloneNotSupportedException} this is a {@link RuntimeException}.
+ *
+ * @author Apache Software Foundation
+ * @since 3.0
+ */
+public class CloneFailedException extends RuntimeException {
+ // ~ Static fields/initializers ---------------------------------------------
+
+ private static final long serialVersionUID = 20091223L;
+
+ // ~ Constructors -----------------------------------------------------------
+
+ /**
+ * Constructs a CloneFailedException.
+ *
+ * @param message description of the exception
+ * @since upcoming
+ */
+ public CloneFailedException(final String message) {
+ super(message);
+ }
+
+ /**
+ * Constructs a CloneFailedException.
+ *
+ * @param cause cause of the exception
+ * @since upcoming
+ */
+ public CloneFailedException(final Throwable cause) {
+ super(cause);
+ }
+
+ /**
+ * Constructs a CloneFailedException.
+ *
+ * @param message description of the exception
+ * @param cause cause of the exception
+ * @since upcoming
+ */
+ public CloneFailedException(final String message, final Throwable cause) {
+ super(message, cause);
+ }
+}
diff --git a/src/test/java/org/apache/commons/lang3/ObjectUtilsTest.java b/src/test/java/org/apache/commons/lang3/ObjectUtilsTest.java
index 448e10d..abbf0dc 100644
--- a/src/test/java/org/apache/commons/lang3/ObjectUtilsTest.java
+++ b/src/test/java/org/apache/commons/lang3/ObjectUtilsTest.java
@@ -21,6 +21,9 @@
import java.util.Calendar;
import java.util.Date;
+import org.apache.commons.lang3.exception.CloneFailedException;
+import org.apache.commons.lang3.mutable.MutableObject;
+
import junit.framework.TestCase;
/**
@@ -212,4 +215,89 @@
assertNull( ObjectUtils.min((String)null, (String)null) );
}
+ /**
+ * Tests {@link ObjectUtils#clone(Object)} with a cloneable object.
+ */
+ public void testCloneOfCloneable() {
+ final CloneableString string = new CloneableString("apache");
+ final CloneableString stringClone = ObjectUtils.clone(string);
+ assertEquals("apache", stringClone.getValue());
+ }
+
+ /**
+ * Tests {@link ObjectUtils#clone(Object)} with a not cloneable object.
+ */
+ public void testCloneOfNotCloneable() {
+ final String string = new String("apache");
+ assertNull(ObjectUtils.clone(string));
+ }
+
+ /**
+ * Tests {@link ObjectUtils#clone(Object)} with an uncloneable object.
+ */
+ public void testCloneOfUncloneable() {
+ final UncloneableString string = new UncloneableString("apache");
+ try {
+ ObjectUtils.clone(string);
+ fail("Thrown " + CloneFailedException.class.getName() + " expected");
+ } catch (final CloneFailedException e) {
+ assertEquals(NoSuchMethodException.class, e.getCause().getClass());
+ }
+ }
+
+ /**
+ * Tests {@link ObjectUtils#cloneIfPossible(Object)} with a cloneable object.
+ */
+ public void testPossibleCloneOfCloneable() {
+ final CloneableString string = new CloneableString("apache");
+ final CloneableString stringClone = ObjectUtils.cloneIfPossible(string);
+ assertEquals("apache", stringClone.getValue());
+ }
+
+ /**
+ * Tests {@link ObjectUtils#cloneIfPossible(Object)} with a not cloneable object.
+ */
+ public void testPossibleCloneOfNotCloneable() {
+ final String string = new String("apache");
+ assertSame(string, ObjectUtils.cloneIfPossible(string));
+ }
+
+ /**
+ * Tests {@link ObjectUtils#cloneIfPossible(Object)} with an uncloneable object.
+ */
+ public void testPossibleCloneOfUncloneable() {
+ final UncloneableString string = new UncloneableString("apache");
+ try {
+ ObjectUtils.cloneIfPossible(string);
+ fail("Thrown " + CloneFailedException.class.getName() + " expected");
+ } catch (final CloneFailedException e) {
+ assertEquals(NoSuchMethodException.class, e.getCause().getClass());
+ }
+ }
+
+ /**
+ * String that is cloneable.
+ */
+ static final class CloneableString extends MutableObject<String> implements Cloneable {
+ private static final long serialVersionUID = 1L;
+ CloneableString(final String s) {
+ super(s);
+ }
+
+ @Override
+ public CloneableString clone() throws CloneNotSupportedException {
+ return (CloneableString)super.clone();
+ }
+ }
+
+ /**
+ * String that is not cloneable.
+ */
+ static final class UncloneableString extends MutableObject<String> implements Cloneable {
+ private static final long serialVersionUID = 1L;
+ UncloneableString(final String s) {
+ super(s);
+ }
+ }
+
}
