RE: [lang] ClassCastException in Enum.compareTo with anonymous inner classes
Hi Jörg,
thanks for your quick response and your approach to solve this issue. But
anyway I think it should be possible to add these Enums to a Set without
throwing a ClassCastException regardless of which class, anonymous inner class
or whatever else the Enum is.
Samuel
-Original Message-
From: Jörg Schaible [mailto:[EMAIL PROTECTED]
Sent: Thursday, September 13, 2007 4:06 PM
To: Jakarta Commons Users List
Subject: RE: [lang] ClassCastException in Enum.compareTo with anonymous inner
classes
Hi Samuel,
Samuel Fleischle wrote on Thursday, September 13, 2007 3:51 PM:
Hi,
I updated from Commons Lang 2.1 to Commons Lang 2.3 and got
some issues with the changed compareTo() method of Enum with
anonymouse inner classes:
Here is my simplified Enum:
public class ItemStatus extends Enum
{
// --
Static Fields
public static final ItemStatus CANCEL = new
ItemStatus(CANCEL, Cancel);
public static final ItemStatus SHIPPED = new
ItemStatus(SHIPPED, Shipped) {
public String getDisplayName() {
// do something special for this status
}
};
public static final ItemStatus MOVED = new
ItemStatus(MOVED, Moved) {
public String getDisplayName() {
// do something special for this status
}
};
[snip]
}
[snip]
com.myapp.common.model.order.ItemStatus
com.myapp.common.model.order.ItemStatus$1
com.myapp.common.model.order.ItemStatus$2
The compareTo-Method now tries to compare ItemStatus$1 with
ItemStatus$2 and says to me, that my ItemStatus-Enums are
different classes.
Well, obviously those *are* different classes.
I saw in JIRA there are some other issues in
ValuedEnum.compareTo(). Is there a bug in the
Enum.compareTo() implementation which got changed in Lang 2.2?
IIRC, this was more about using different class loaders loading the EnumValue
class.
Thanks in advance for any help or comment on this issue.
Why don't you factor out a (private) interface with this method? Write an
addition ctor that takes such an implementation and use otherwise a default
one. With this approach the enum class is always the same and the anonymous
class is of a different type. Make the an additional field in the enum class
keeping that implementation and declare it as transient for seamless
serialization.
- Jörg
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RE: [lang] ClassCastException in Enum.compareTo with anonymous inner classes
Samuel Fleischle wrote on Friday, September 14, 2007 9:19 AM: Hi Jörg, thanks for your quick response and your approach to solve this issue. But anyway I think it should be possible to add these Enums to a Set without throwing a ClassCastException regardless of which class, anonymous inner class or whatever else the Enum is. Well, this is what is excplicitly documented in the JDK's docs for Comparable.compareTo(). The ValueEnum must ensure that it does not compare apples and oranges and two different classes imply this. The exception was surprising for you, since the old version of CL simply did this, but I'd rather declare that impl of compareTo as buggy ;-) - Jörg - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: [lang] ClassCastException in Enum.compareTo with anonymous inner classes
Hi,
I updated from Commons Lang 2.1 to Commons Lang 2.3 and got some issues with
the changed compareTo() method of Enum with anonymouse inner classes:
Here is my simplified Enum:
public class ItemStatus extends Enum
{
// -- Static Fields
public static final ItemStatus CANCEL = new ItemStatus(CANCEL,
Cancel);
public static final ItemStatus SHIPPED = new ItemStatus(SHIPPED,
Shipped) {
public String getDisplayName() {
// do something special for this status
}
};
public static final ItemStatus MOVED = new ItemStatus(MOVED, Moved) {
public String getDisplayName() {
// do something special for this status
}
};
/** Contains each status. */
private static Set statuses;
// -- Instance Fields
/** Name to display in user interfaces. */
private final String displayName;
// --- Constructors
protected ItemStatus(String name, String displayName) {
super(name);
this.displayName = displayName;
System.out.println(this.getClass().getName());
buildStatusSet();
}
// --- Static Methods
/**
* Returns the item status enumeration object
* for the given status name.
*
* @param itemStatus
* name of the item status
* @return the enumeration object, or codenull/code if it does not
* exist
*/
public static ItemStatus valueOf(String itemStatus) {
return (ItemStatus) getEnum(ItemStatus.class, itemStatus);
}
// --- Public Methods
/**
* [EMAIL PROTECTED]
*/
// @Override
public final Class getEnumClass() {
return ItemStatus.class;
}
/**
* Gets all defined ItemStatus.
*
* @return the enum object List
* @see org.apache.commons.lang.enums.Enum#getEnumList(Class)
*/
public static List getEnumList() {
return getEnumList(ItemStatus.class);
}
public String getDisplayName() {
return displayName;
}
// --- Private Methods
/**
* Adds the status name to a Set of status names.
*/
private void buildStatusSet() {
if (statuses == null) {
statuses = new TreeSet();
}
statuses.add(this);
}
}
And I got the ClassCastExcetion in the private buildStatusSet()-Method if I
try to add the status to the TreeSet. The TreeSet calls the compareTo-Method of
the Enum. In Commons Lang 2.2 this method was changed with an additional
comparison of the classes.
In my constructor I added a System.out.println of the instantiated classes and
got the following output for the classnames:
com.myapp.common.model.order.ItemStatus
com.myapp.common.model.order.ItemStatus$1
com.myapp.common.model.order.ItemStatus$2
The compareTo-Method now tries to compare ItemStatus$1 with ItemStatus$2 and
says to me, that my ItemStatus-Enums are different classes.
I saw in JIRA there are some other issues in ValuedEnum.compareTo(). Is there a
bug in the Enum.compareTo() implementation which got changed in Lang 2.2?
Thanks in advance for any help or comment on this issue.
Regards,
Sam
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
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RE: [lang] ClassCastException in Enum.compareTo with anonymous inner classes
Hi Samuel,
Samuel Fleischle wrote on Thursday, September 13, 2007 3:51 PM:
Hi,
I updated from Commons Lang 2.1 to Commons Lang 2.3 and got
some issues with the changed compareTo() method of Enum with
anonymouse inner classes:
Here is my simplified Enum:
public class ItemStatus extends Enum
{
// --
Static Fields
public static final ItemStatus CANCEL = new
ItemStatus(CANCEL, Cancel);
public static final ItemStatus SHIPPED = new
ItemStatus(SHIPPED, Shipped) {
public String getDisplayName() {
// do something special for this status
}
};
public static final ItemStatus MOVED = new
ItemStatus(MOVED, Moved) {
public String getDisplayName() {
// do something special for this status
}
};
[snip]
}
[snip]
com.myapp.common.model.order.ItemStatus
com.myapp.common.model.order.ItemStatus$1
com.myapp.common.model.order.ItemStatus$2
The compareTo-Method now tries to compare ItemStatus$1 with
ItemStatus$2 and says to me, that my ItemStatus-Enums are
different classes.
Well, obviously those *are* different classes.
I saw in JIRA there are some other issues in
ValuedEnum.compareTo(). Is there a bug in the
Enum.compareTo() implementation which got changed in Lang 2.2?
IIRC, this was more about using different class loaders loading the EnumValue
class.
Thanks in advance for any help or comment on this issue.
Why don't you factor out a (private) interface with this method? Write an
addition ctor that takes such an implementation and use otherwise a default
one. With this approach the enum class is always the same and the anonymous
class is of a different type. Make the an additional field in the enum class
keeping that implementation and declare it as transient for seamless
serialization.
- Jörg
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
