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https://issues.apache.org/jira/browse/LANG-576?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Joerg Schaible updated LANG-576:
--------------------------------
Description:
Object.clone is declared protected, which makes it impossible to write code
like:
{code:java}
if (obj instanceof Cloneable) {
Object clone = obj.clone();
...
}
{code}
Following two methods will help in such a situation:
{code:java}
/**
* 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;
}
{code}
Comments? Note, that the code currently introduces also a new
CloneFailedException. Use another existing one?
Unit tests will be provided also.
was:
Object.clone is declared protected, which makes it impossible to write code
like:
{code:java}
if (obj instanceof Cloneable) {
Object clone = obj.clone();
...
}
{code}
Following two methods will help in such a situation:
{code:java}
/**
* 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
*/
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
*/
public static <T> T cloneIfPossible(final T o) {
final T clone = clone(o);
return clone == null ? o : clone;
}
{code}
Comments?
Unit tests will be provided also.
> Add methods for cloneables to ObjectUtils
> -----------------------------------------
>
> Key: LANG-576
> URL: https://issues.apache.org/jira/browse/LANG-576
> Project: Commons Lang
> Issue Type: New Feature
> Components: lang.*
> Reporter: Joerg Schaible
> Assignee: Joerg Schaible
> Priority: Minor
> Fix For: 3.0
>
> Attachments: Cloneable.diff
>
>
> Object.clone is declared protected, which makes it impossible to write code
> like:
> {code:java}
> if (obj instanceof Cloneable) {
> Object clone = obj.clone();
> ...
> }
> {code}
> Following two methods will help in such a situation:
> {code:java}
> /**
> * 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;
> }
> {code}
> Comments? Note, that the code currently introduces also a new
> CloneFailedException. Use another existing one?
> Unit tests will be provided also.
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