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Posted to dev@harmony.apache.org by "lcj.dev" <lc...@gmail.com> on 2010/11/16 14:44:33 UTC
Question about Character.valueOf()
Hi, all
Why this may be failed for other JREs? assertSame(Character.valueOf(c), Character.valueOf(c)).
Thanks.
please refers to this test case for details:
package org.apache.harmony.luni.tests.java.lang;
import junit.framework.TestCase;
public class CharacterImplTest extends TestCase {
public void test_valueOfC() {
// test the cache range
for (char c = '\u0000'; c < 512; c++) {
Character e = new Character(c);
Character a = Character.valueOf(c);
assertEquals(e, a);
// WARN: this assertion may not be valid on other JREs
assertSame(Character.valueOf(c), Character.valueOf(c));
}
// test the rest of the chars
for (int c = '\u0512'; c <= Character.MAX_VALUE; c++) {
assertEquals(new Character((char) c), Character.valueOf((char) c));
}
}
}
2010-11-16
lcj.dev
Re: Question about Character.valueOf()
Posted by liou <lc...@gmail.com>.
Does that means impl of harmony widened the range on the jls from
0-127 to 0-512?
On Tue, Nov 16, 2010 at 11:23 PM, sebb <se...@gmail.com> wrote:
>
> Yes, but the point is that there is at least a partial guarantee.
>
> On 16 November 2010 14:55, Mikael <mi...@telia.com> wrote:
> > But that's only for Character 0x00 to 0x7F, the loop with the assert test
> > counts from 0 to 512.
> >
> > ----- Original Message ----- From: "sebb" <se...@gmail.com>
> > To: <de...@harmony.apache.org>
> > Sent: Tuesday, November 16, 2010 3:42 PM
> > Subject: Re: Question about Character.valueOf()
> >
> >
> > The end of section 5.1.7
> >
> > http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.1.7
> >
> > says:
> >
> > "If the value p being boxed is true, false, a byte, a char in the
> > range \u0000 to \u007f, or an int or short number between -128 and
> > 127, then let r1 and r2 be the results of any two boxing conversions
> > of p. It is always the case that r1 == r2."
> >
> > [See also subsequent discussion section]
> >
> > AFAIK, boxing uses valueOf to achieve this.
> >
> > On 16 November 2010 13:50, Mikael <mi...@telia.com> wrote:
> >>
> >> As far as I know there is no guarantee that valueOf returns the same
> >> object
> >> every time, it just gives class a chance to do it if it wants to.
> >>
> >> ----- Original Message ----- From: "lcj.dev" <lc...@gmail.com>
> >> To: "dev" <de...@harmony.apache.org>
> >> Sent: Tuesday, November 16, 2010 2:44 PM
> >> Subject: Question about Character.valueOf()
> >>
> >>
> >>> Hi, all
> >>> Why this may be failed for other JREs? assertSame(Character.valueOf(c),
> >>> Character.valueOf(c)).
> >>> Thanks.
> >>>
> >>> please refers to this test case for details:
> >>> package org.apache.harmony.luni.tests.java.lang;
> >>>
> >>> import junit.framework.TestCase;
> >>>
> >>> public class CharacterImplTest extends TestCase {
> >>>
> >>> public void test_valueOfC() {
> >>> // test the cache range
> >>> for (char c = '\u0000'; c < 512; c++) {
> >>> Character e = new Character(c);
> >>> Character a = Character.valueOf(c);
> >>> assertEquals(e, a);
> >>>
> >>> // WARN: this assertion may not be valid on other JREs
> >>> assertSame(Character.valueOf(c), Character.valueOf(c));
> >>> }
> >>> // test the rest of the chars
> >>> for (int c = '\u0512'; c <= Character.MAX_VALUE; c++) {
> >>> assertEquals(new Character((char) c), Character.valueOf((char)
> >>> c));
> >>> }
> >>> }
> >>> }
> >>> 2010-11-16
> >>>
> >>>
> >>>
> >>> lcj.dev
> >>
> >>
> >
> >
Re: Question about Character.valueOf()
Posted by sebb <se...@gmail.com>.
Yes, but the point is that there is at least a partial guarantee.
On 16 November 2010 14:55, Mikael <mi...@telia.com> wrote:
> But that's only for Character 0x00 to 0x7F, the loop with the assert test
> counts from 0 to 512.
>
> ----- Original Message ----- From: "sebb" <se...@gmail.com>
> To: <de...@harmony.apache.org>
> Sent: Tuesday, November 16, 2010 3:42 PM
> Subject: Re: Question about Character.valueOf()
>
>
> The end of section 5.1.7
>
> http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.1.7
>
> says:
>
> "If the value p being boxed is true, false, a byte, a char in the
> range \u0000 to \u007f, or an int or short number between -128 and
> 127, then let r1 and r2 be the results of any two boxing conversions
> of p. It is always the case that r1 == r2."
>
> [See also subsequent discussion section]
>
> AFAIK, boxing uses valueOf to achieve this.
>
> On 16 November 2010 13:50, Mikael <mi...@telia.com> wrote:
>>
>> As far as I know there is no guarantee that valueOf returns the same
>> object
>> every time, it just gives class a chance to do it if it wants to.
>>
>> ----- Original Message ----- From: "lcj.dev" <lc...@gmail.com>
>> To: "dev" <de...@harmony.apache.org>
>> Sent: Tuesday, November 16, 2010 2:44 PM
>> Subject: Question about Character.valueOf()
>>
>>
>>> Hi, all
>>> Why this may be failed for other JREs? assertSame(Character.valueOf(c),
>>> Character.valueOf(c)).
>>> Thanks.
>>>
>>> please refers to this test case for details:
>>> package org.apache.harmony.luni.tests.java.lang;
>>>
>>> import junit.framework.TestCase;
>>>
>>> public class CharacterImplTest extends TestCase {
>>>
>>> public void test_valueOfC() {
>>> // test the cache range
>>> for (char c = '\u0000'; c < 512; c++) {
>>> Character e = new Character(c);
>>> Character a = Character.valueOf(c);
>>> assertEquals(e, a);
>>>
>>> // WARN: this assertion may not be valid on other JREs
>>> assertSame(Character.valueOf(c), Character.valueOf(c));
>>> }
>>> // test the rest of the chars
>>> for (int c = '\u0512'; c <= Character.MAX_VALUE; c++) {
>>> assertEquals(new Character((char) c), Character.valueOf((char)
>>> c));
>>> }
>>> }
>>> }
>>> 2010-11-16
>>>
>>>
>>>
>>> lcj.dev
>>
>>
>
>
Re: Question about Character.valueOf()
Posted by Mikael <mi...@telia.com>.
But that's only for Character 0x00 to 0x7F, the loop with the assert test
counts from 0 to 512.
----- Original Message -----
From: "sebb" <se...@gmail.com>
To: <de...@harmony.apache.org>
Sent: Tuesday, November 16, 2010 3:42 PM
Subject: Re: Question about Character.valueOf()
The end of section 5.1.7
http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.1.7
says:
"If the value p being boxed is true, false, a byte, a char in the
range \u0000 to \u007f, or an int or short number between -128 and
127, then let r1 and r2 be the results of any two boxing conversions
of p. It is always the case that r1 == r2."
[See also subsequent discussion section]
AFAIK, boxing uses valueOf to achieve this.
On 16 November 2010 13:50, Mikael <mi...@telia.com> wrote:
> As far as I know there is no guarantee that valueOf returns the same
> object
> every time, it just gives class a chance to do it if it wants to.
>
> ----- Original Message ----- From: "lcj.dev" <lc...@gmail.com>
> To: "dev" <de...@harmony.apache.org>
> Sent: Tuesday, November 16, 2010 2:44 PM
> Subject: Question about Character.valueOf()
>
>
>> Hi, all
>> Why this may be failed for other JREs? assertSame(Character.valueOf(c),
>> Character.valueOf(c)).
>> Thanks.
>>
>> please refers to this test case for details:
>> package org.apache.harmony.luni.tests.java.lang;
>>
>> import junit.framework.TestCase;
>>
>> public class CharacterImplTest extends TestCase {
>>
>> public void test_valueOfC() {
>> // test the cache range
>> for (char c = '\u0000'; c < 512; c++) {
>> Character e = new Character(c);
>> Character a = Character.valueOf(c);
>> assertEquals(e, a);
>>
>> // WARN: this assertion may not be valid on other JREs
>> assertSame(Character.valueOf(c), Character.valueOf(c));
>> }
>> // test the rest of the chars
>> for (int c = '\u0512'; c <= Character.MAX_VALUE; c++) {
>> assertEquals(new Character((char) c), Character.valueOf((char)
>> c));
>> }
>> }
>> }
>> 2010-11-16
>>
>>
>>
>> lcj.dev
>
>
Re: Question about Character.valueOf()
Posted by sebb <se...@gmail.com>.
The end of section 5.1.7
http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.1.7
says:
"If the value p being boxed is true, false, a byte, a char in the
range \u0000 to \u007f, or an int or short number between -128 and
127, then let r1 and r2 be the results of any two boxing conversions
of p. It is always the case that r1 == r2."
[See also subsequent discussion section]
AFAIK, boxing uses valueOf to achieve this.
On 16 November 2010 13:50, Mikael <mi...@telia.com> wrote:
> As far as I know there is no guarantee that valueOf returns the same object
> every time, it just gives class a chance to do it if it wants to.
>
> ----- Original Message ----- From: "lcj.dev" <lc...@gmail.com>
> To: "dev" <de...@harmony.apache.org>
> Sent: Tuesday, November 16, 2010 2:44 PM
> Subject: Question about Character.valueOf()
>
>
>> Hi, all
>> Why this may be failed for other JREs? assertSame(Character.valueOf(c),
>> Character.valueOf(c)).
>> Thanks.
>>
>> please refers to this test case for details:
>> package org.apache.harmony.luni.tests.java.lang;
>>
>> import junit.framework.TestCase;
>>
>> public class CharacterImplTest extends TestCase {
>>
>> public void test_valueOfC() {
>> // test the cache range
>> for (char c = '\u0000'; c < 512; c++) {
>> Character e = new Character(c);
>> Character a = Character.valueOf(c);
>> assertEquals(e, a);
>>
>> // WARN: this assertion may not be valid on other JREs
>> assertSame(Character.valueOf(c), Character.valueOf(c));
>> }
>> // test the rest of the chars
>> for (int c = '\u0512'; c <= Character.MAX_VALUE; c++) {
>> assertEquals(new Character((char) c), Character.valueOf((char)
>> c));
>> }
>> }
>> }
>> 2010-11-16
>>
>>
>>
>> lcj.dev
>
>
Re: Question about Character.valueOf()
Posted by Mikael <mi...@telia.com>.
As far as I know there is no guarantee that valueOf returns the same object
every time, it just gives class a chance to do it if it wants to.
----- Original Message -----
From: "lcj.dev" <lc...@gmail.com>
To: "dev" <de...@harmony.apache.org>
Sent: Tuesday, November 16, 2010 2:44 PM
Subject: Question about Character.valueOf()
> Hi, all
> Why this may be failed for other JREs? assertSame(Character.valueOf(c),
> Character.valueOf(c)).
> Thanks.
>
> please refers to this test case for details:
> package org.apache.harmony.luni.tests.java.lang;
>
> import junit.framework.TestCase;
>
> public class CharacterImplTest extends TestCase {
>
> public void test_valueOfC() {
> // test the cache range
> for (char c = '\u0000'; c < 512; c++) {
> Character e = new Character(c);
> Character a = Character.valueOf(c);
> assertEquals(e, a);
>
> // WARN: this assertion may not be valid on other JREs
> assertSame(Character.valueOf(c), Character.valueOf(c));
> }
> // test the rest of the chars
> for (int c = '\u0512'; c <= Character.MAX_VALUE; c++) {
> assertEquals(new Character((char) c), Character.valueOf((char)
> c));
> }
> }
> }
> 2010-11-16
>
>
>
> lcj.dev