diff --git a/src/main/java/org/apache/commons/lang3/ObjectUtils.java b/src/main/java/org/apache/commons/lang3/ObjectUtils.java index fdfc468f9..e2b2cf08c 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; /** *

Operations on Object.

@@ -309,6 +313,48 @@ public static > T max(T c1, T c2) { return c1 != null ? c1 : c2; } } + + /** + * Clone an object. + * + * @param the type of the object + * @param o the object to clone + * @return the clone if the object implements {@link Cloneable} otherwise null + * @throws CloneFailedException if the object is cloneable and the clone operation fails + * @since 3.0 + */ + public static 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 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 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 000000000..7bef6ddf6 --- /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 448e10d6b..abbf0dc62 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 @@ public void testMin() { 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 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 implements Cloneable { + private static final long serialVersionUID = 1L; + UncloneableString(final String s) { + super(s); + } + } + }