hg: lambda/lambda/jdk: 2 new changesets

[Roel Spilker]

Two more things on the current implementation:

9) The javadoc has some typos: `nullOuput` instead of `nullOutput` or even
better "null"

A) In addAll the prepareBuilder is invoked inside the loop.

Roel

On Mon, Jun 25, 2012 at 6:14 PM, Jim Gish <jim.gish at oracle.com> wrote:

> Thanks for the feedback, Roel.  I'll take a look at the suggested code
> changes in a bit.  As far as your enhancement suggestions go for
> null/empty, I started off with something comparable, but was urged to keep
> it simple for this initial round.  However, I hope to add these at some
> point.
>
> Thanks,
>   Jim
>
>
> On 06/25/2012 11:37 AM, Roel Spilker wrote:
>
>> Regarding the API, I can also imagine the need/wish for special handling
>> of
>> null and empty values.
>>
>> /** Treat null values as if the weren't there*/
>> StringJoiner ignoreNull() {};
>>
>> /** Replace null values by the given value*/
>> StringJoiner useForNull(String nullString) {};
>>
>> /** Treat empty values as if the weren't there*/
>> StringJoiner ignoreEmpty() {};
>>
>> /** Replace empty values by the given value*/
>> StringJoiner useForNull(String emptyString) {};
>>
>> Roel
>>
>> On Mon, Jun 25, 2012 at 5:23 PM, Roel Spilker<r.spilker at gmail.com>
>>  wrote:
>>
>>  I understand the need, and give feedback on the implementation, assuming
>>> the current API.
>>>
>>> Feedback on the implementation of StringJoiner.java
>>>
>>> 1) The field `nullOutput` could become a constant, since there it is
>>> never
>>> written to:
>>> private static final String NULL_OUTPUT = "null";
>>>
>>> 2) There is no need for the field `nullOutputChars`. It is only used
>>> once,
>>> in add(char[]) . This could easily be rewritten to:
>>>
>>> public StringJoiner add(char[] newElement) {
>>> prepareBuilder();
>>> if (newElement == null) {
>>>  value.add(NULL_OUTPUT);
>>> } else {
>>> value.add(newElement);
>>>  }
>>> return this;
>>> }
>>>
>>> 3) `toString` calls `emptyOutput.toString()`. There is no need for that;
>>> it is already a String.
>>>
>>> 4) The field `prefixLen` can be removed entirely. It is only used in
>>> prepareBuilder the first time something is added. Actually, I think that
>>> the code `if (prefixLen>  0)` can be ommitted at all, but at least it can
>>> be replaced by `if (prefix.length()>  0)`
>>>
>>> 5) In `subSequence`, instead of creating a StringBuilder using the
>>> CharSequence constructor, I think it is better to create a StringBuilder
>>> of
>>> the right size and then append the subSequences of the `value` and
>>> `suffix`:
>>>
>>> if (start<  value.length()) {
>>> return new StringBuilder(end - start)
>>> .append(value.subSequence( start, value.length()))
>>>  .append(suffix.subSequence( 0, end - value.length());
>>> }
>>>
>>> 6) In the constructor, in the common case there is no need for String
>>> concatenation:
>>> this.emptyOutput = this.suffix.isEmpty() ? this.prefix : this.prefix +
>>> this.suffix;
>>>
>>> 7) `asChars`, `asCharArray` and `asCodePoints` be made much simpler by
>>> calling toString (or a private method toStringInternal, ontaining the
>>> current toString implementation, since a subclass might have overridden
>>> toString) and than delegate the call:
>>>
>>> public Iterable<Character>  asChars() {
>>> return toStringInternal().asChars();
>>> }
>>>
>>> public char[] asCharArray() {
>>>  return toStringInternal().**asCharArray();
>>> }
>>>
>>> public Iterable<Integer>  asCodePoints() {
>>> return toStringInternal().**asCodePoints();
>>> }
>>>
>>> This also takes care of the current inconsistencies beween `asCharArray`
>>> and the other two methods.
>>>
>>> 8) Possibly get rid of the `prefix` field by adding it directly to the
>>> `value` field in the constructor:
>>>
>>> String prefixValue = prefix.toString();
>>> this.emptyOutput = this.suffix.isEmpty() ? prefixValue : prefixValue +
>>> this.suffix;
>>> this.value = new StringBuilder().append(**prefixValue);
>>>
>>> On all code paths, the field `somethingAdded` is checked before reading
>>> the `value` field.
>>>
>>> The method `prepareBuilder` would then become:
>>>
>>> if (!somethingAdded) {
>>>  somethingAdded = true;
>>> } else {
>>> value.append(infix);
>>> }
>>>
>>> Removing the field is obviously a good thing. The downside is that the
>>> contents of the prefix is now always copied to the `value` field, even
>>> when
>>> no actual values are added. Then again, I expect the prefix to be empty
>>> in
>>> most of the use cases.
>>>
>>> Roel
>>>
>>>
>>> On Mon, Jun 25, 2012 at 4:29 PM, Brian Goetz<brian.goetz at oracle.com>**
>>> wrote:
>>>
>>>  This is a reasonable place for such feedback.
>>>>
>>>> The motivation for StringJoiner was twofold:
>>>>  - to address the long-standing RFE for String.join;
>>>>  - to provide an easy means of joining a stream of strings (e.g., names
>>>> =
>>>> people.map(Person::getName).****into(new StringJoiner(", "))
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On 6/25/2012 7:56 AM, Roel Spilker wrote:
>>>>
>>>>  I have some feedback on the implementation of StringJoiner. Where and
>>>>> how
>>>>> can I give this feedback?
>>>>>
>>>>> Roel
>>>>>
>>>>> On Sat, Jun 23, 2012 at 3:10 AM,<stuart.marks at oracle.com>   wrote:
>>>>>
>>>>>  Changeset: 915296b3c16e
>>>>>
>>>>>> Author:    jgish
>>>>>> Date:      2012-06-20 18:40 -0400
>>>>>> URL:       http://hg.openjdk.java.net/****lambda/lambda/jdk/rev/**<http://hg.openjdk.java.net/**lambda/lambda/jdk/rev/**>
>>>>>> 915296b3c16e<http://hg.**openjdk.java.net/lambda/**
>>>>>> lambda/jdk/rev/915296b3c16e<http://hg.openjdk.java.net/lambda/lambda/jdk/rev/915296b3c16e>
>>>>>> >
>>>>>>
>>>>>>
>>>>>> 5015163: (str) String merge/join that is the inverse of String.split()
>>>>>> Summary: Convenience methods on String to access the
>>>>>> java.util.StringJoiner functionality
>>>>>> Reviewed-by: smarks, briangoetz
>>>>>>
>>>>>> ! src/share/classes/java/lang/****AbstractStringBuilder.java
>>>>>> ! src/share/classes/java/lang/****String.java
>>>>>> ! src/share/classes/java/lang/****StringBuffer.java
>>>>>> ! src/share/classes/java/lang/****StringBuilder.java
>>>>>> ! src/share/classes/java/util/****StringJoiner.java
>>>>>> ! test-ng/tests/org/openjdk/****tests/java/lang/StringTest.****java
>>>>>> ! test-ng/tests/org/openjdk/****tests/java/util/****
>>>>>> FillableStringTest.java
>>>>>> ! test-ng/tests/org/openjdk/****tests/java/util/****
>>>>>> StringJoinerTest.java
>>>>>>
>>>>>>
>>>>>> Changeset: 7af64c20ebe7
>>>>>> Author:    smarks
>>>>>> Date:      2012-06-22 18:12 -0700
>>>>>> URL:       http://hg.openjdk.java.net/****lambda/lambda/jdk/rev/**<http://hg.openjdk.java.net/**lambda/lambda/jdk/rev/**>
>>>>>> 7af64c20ebe7<http://hg.**openjdk.java.net/lambda/**
>>>>>> lambda/jdk/rev/7af64c20ebe7<http://hg.openjdk.java.net/lambda/lambda/jdk/rev/7af64c20ebe7>
>>>>>> >
>>>>>>
>>>>>> merge
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
> --
> Jim Gish | Consulting Member of Technical Staff | +1.781.442.0304
> Oracle Java Platform Group | Core Libraries Team
> 35 Network Drive
> Burlington, MA 01803
> jim.gish at oracle.com
>
>