Do you have any ideas where these classes can appear? As far as I understand TreeMap#headMap() as well as #subMap() and #tailMap() returns instances of TreeMap$SubMap.
Yes.
IMHO if we cannot get instances of these $1 - $3 classes we should not care about it.
But we can get SubMap instance. And its serialization/deserialization is partly broken in RI. As far as I understood the question is: should we implement the functionality that is partly broken in RI? But if there is SubMap already in the TreeMap, why not make a compatible serialization for it, knowing form? It will be broken in the same way with RI and work correct with Harmony classlib... On 8/7/06, Alexei Zakharov <[EMAIL PROTECTED]> wrote:
Hi Spark, > > > IIRC, there are three mysterious serialized form immediately following > > > the serialized form of java.util.TreeMap. They are > > > Class **java.util.TreeMap$1** > > > Class **java.util.TreeMap$2** > > > Class **java.util.TreeMap$3** Do you have any ideas where these classes can appear? As far as I understand TreeMap#headMap() as well as #subMap() and #tailMap() returns instances of TreeMap$SubMap. IMHO if we cannot get instances of these $1 - $3 classes we should not care about it. There are several places in the J2SE 5.0 api doc where serialization form for non-public classes is described. Regards, 2006/8/7, Ilya Okomin <[EMAIL PROTECTED]>: > On 8/7/06, Oleg Khaschansky <[EMAIL PROTECTED]> wrote: > > > > Hi, > > > > Take a look at this: > > http://download.java.net/jdk6/docs/api/serialized-form.html > > Maybe this document will give you an idea of what are those inner > > classes... Of cause, in the new release serialized form may have > > changed. > > > Oleg, ASFAIK the main issue is that TreeMap.headMap() returns the private > implemention of SortedMap class. This SortedMap implementation serializable > on RI, but it is undocumented in the spec. Spark Shen has just provided > tests that show strange behavior of serialization and deserialization of > this SortedMap implementation on RI. > I'm not sure we can find anything usefull on the link you've provided, > because there only serialization forms for public classes are described (if > I'm not mistaken:)). > > Thanks, > Ilya. > > -- > > Oleg > > > > On 8/7/06, Spark Shen <[EMAIL PROTECTED]> wrote: > > > Hi: > > > This is a long post, thanks for your patient to read it through :-) > > > > > > I wrote a test case as below: > > > public void test_SubMap_Serializable() throws Exception { > > > TreeMap<Integer, Double> map = new TreeMap<Integer, Double>(); > > > map.put(1, 2.1); > > > map.put(2, 3.1); > > > map.put(3, 4.5); > > > map.put(7, 21.3); > > > SortedMap<Integer, Double> headMap = map.headMap(3); > > > assertTrue(headMap instanceof Serializable); > > > assertFalse(headMap instanceof TreeMap); > > > assertTrue(headMap instanceof SortedMap); > > > } > > > Which says the returned headMap is not a TreeMap but a serializable > > > SortedMap. > > > > > > IIRC, there are three mysterious serialized form immediately following > > > the serialized form of java.util.TreeMap. They are > > > > > > Class **java.util.TreeMap$1** extends Object implements Serializable > > > > > > Class **java.util.TreeMap$2** extends Object implements Serializable > > > > > > Class **java.util.TreeMap$3** extends Object implements Serializable > > > > > > respectively. This gives a hint that there are three inner classes of > > > TreeMap which should be serializable. > > > But what are they indeed? > > > IMHO, the returned SortedMap may > > > be one of the java.util.TreeMap$x classes. What is your opinion? (I > > > raised JIRA-1066 for this) > > > > > > The above test case suggests me to make the returned SortedMap > > > serializable. But, I have another concern: > > > SortedMap returned by TreeMap is not a public class(does not have a > > > documented Serialized form), and the serialization behavior of this > > > SortedMap is strange. See the test case below: > > > public void test_HeadMap_Serializable() throws Exception { > > > TreeMap<Integer, Double> map = new TreeMap<Integer, Double>(); > > > map.put(1, 2.1); > > > map.put(2, 3.1); > > > map.put(3, 4.5); > > > map.put(7, 21.3); > > > SortedMap<Integer, Double> headMap = map.headMap(3); > > > assertTrue(headMap instanceof Serializable); > > > assertFalse(headMap instanceof TreeMap); > > > assertTrue(headMap instanceof SortedMap); > > > > > > // Write the SortedMap out and read it back. > > > ByteArrayOutputStream bos = new ByteArrayOutputStream(); > > > ObjectOutputStream oos = new ObjectOutputStream(bos); > > > oos.writeObject(headMap); > > > oos.close(); > > > > > > ByteArrayInputStream bis = new > > > ByteArrayInputStream(bos.toByteArray()); > > > ObjectInputStream ois = new ObjectInputStream(bis); > > > Object outputObject = (Object) ois.readObject(); > > > > > > *assertNull(((SortedMap)outputObject).entrySet()); > > > > > > assertNotNull(((SortedMap)outputObject).keySet()); > > > > > > assertNotNull(((SortedMap)outputObject).values()); > > > > > > * *// assertEquals(outputObject, headMap);* > > > } > > > > > > The commented out assertion will throw out a NullPointerException, and > > > the entrySet of the SortedMap is Null while keySet and values are not. > > > This is strange. Do we need to follow RI to make the returned SortedMap > > > serializable like this? > > > > > > Best regards > > > > > > -- > > > Spark Shen > > > China Software Development Lab, IBM > > > > -- > Ilya Okomin > Intel Middleware Products Division > > -- Alexei Zakharov, Intel Middleware Product Division --------------------------------------------------------------------- Terms of use : http://incubator.apache.org/harmony/mailing.html To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
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