[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13039254#comment-13039254 ] Brent Worden commented on COLLECTIONS-213: -- IteratorIterable now supports multiple use implicitly through ResettableIterator instances as well as by wrapping non-resettable iterators in ListIteratorWrapper. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Assignee: Brent Worden Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java, collections-4.0-213.diff I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[
https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13038586#comment-13038586
]
Matt Benson commented on COLLECTIONS-213:
-
I would argue that the contract of Iterable suggests implicitly that multiple
.iterator() calls will return multiple Iterator instances. This is not
necessarily about resetting the original instance so much as forking it. I
would either make this the default behavior of IteratorIterable, or forego the
public constructor in favor of descriptive factory methods, e.g.:
{{IteratorIterable.adaptForSingleUse(Iterator)}}
{{IteratorIterable.adaptForMultipleUse(Iterator)}}
CollectionUtils API extension: algorithm methods accept an Iterator argument
Key: COLLECTIONS-213
URL: https://issues.apache.org/jira/browse/COLLECTIONS-213
Project: Commons Collections
Issue Type: Improvement
Components: Core
Reporter: Dusan Chromy
Assignee: Brent Worden
Fix For: 4.x
Attachments: COLLECTIONS-213.patch, CollectionUtils.java,
TestCollectionUtils.java, collections-4.0-213.diff
I just finished the Iterator additions to CollectionUtils, including test
cases and I am going to
attach them to this issue very shortly (basically as soon as I figure out how
attaching in JIRA works :)
At first I was thinking for a while whether CollectionUtils is a good place
to accomodate the methods with the
new signature, until I noticed the collect method already accepts an Iterator
argument.
Following methods now accept an Iterator argument (besides collect):
cardinality
find
forAllDo
countMatches
exists
I also noticed cardinality used to throw a NPE if the collection argument was
null.
I see no reason why it should not return zero. The Iterator flavour does
return zero
and I also modified the Collection version to return zero (including Javadoc
modification) for the sake of consistence.
I stopped to think for a while before touching the method, but the fact
that the Javadoc does not mention may not be null made me think the NPE is
not thrown
intentionally. And after all, cardinality(..) is nothing else than
specialized countMatches(..),
which returns 0 for null collection. However, feel free to reject the change
to the cardinality(Object,Collection)
method if you think otherwise.
I worked on a fresh checkout from subversion and I just updated few minutes
ago to make sure I have modified
the latest version. Anyway, please double-check before commiting the changes.
Cheers,
Dusan
I think that these methods would make useful additions to the API.
I don't have the time to do much collections work these days, but if you
want to code the methods with test cases and attach them to JIRA then that
would be great.
Stephen
dusan.chr...@freenet.de wrote:
I've been using some algorithm methods from the CollectionUtils, for
example
find(Collection, Predicate)
exists(Collection, Predicate)
countMatches(Collection, Predicate)
forAllDo(Collection, Closure)
However, I would also like to be able to use these algorithms with an
Iterator:
find(Iterator, Predicate)
exists(Iterator, Predicate)
countMatches(Iterator, Predicate)
forAllDo(Iterator, Closure)
The obvious workaround is to use IteratorUtils.toList(Iterator), however
this comes at the cost of constructing a list object (an ArrayList
presumably) which could be avoided, as the Iterator itself is sufficient
for the above algorithms to work.
What do you think? Is there any reason not to provide the algorithms for
an Iterator? I personally think that the algorithms should have been
there for Iterators in the first place, because every collection is
Iterable (or has an Iterator, prior to JDK 5.0).
If noone is interested or has time to implement these changes, I can also
contribute to the project - but at the moment I just wanted to discuss
the idea / check if this has been already considered or planned.
Best Regards,
Dusan Chromy
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13038595#comment-13038595 ] Stephen Colebourne commented on COLLECTIONS-213: Dont forget that [collections] has ResettableIterator, so there is another case to consider. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Assignee: Brent Worden Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java, collections-4.0-213.diff I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13038361#comment-13038361 ] Brent Worden commented on COLLECTIONS-213: -- r1126836. Added IteratorIterable adaptor type. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Assignee: Brent Worden Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java, collections-4.0-213.diff I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13038362#comment-13038362 ] Brent Worden commented on COLLECTIONS-213: -- To address Matt Benson's concern, should the IteratorIterable class be modified to work with resettable iterators or should a separate iterable adaptor class be created? CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Assignee: Brent Worden Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java, collections-4.0-213.diff I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13037442#comment-13037442 ] Stephen Colebourne commented on COLLECTIONS-213: I believe am Iterable implementation that wraps an Iterator is a very good idea for [collections] and simplifying its API. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Assignee: Brent Worden Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java, collections-4.0-213.diff I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13037503#comment-13037503 ] Matt Benson commented on COLLECTIONS-213: - It would seem appropriate for an animal to cache the contents of the original iterator to support additional calls. There could be multiple factory methods to get Iterable instances with or without this behavior. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Assignee: Brent Worden Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java, collections-4.0-213.diff I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13036857#comment-13036857 ] Brent Worden commented on COLLECTIONS-213: -- +1 on the iterator based method additions. With the rise of big data frameworks, having to operate on iterators directly is becoming more common. For instance Hadoop's reducers work with iterators and not collections or iterables. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13036909#comment-13036909 ] Brent Worden commented on COLLECTIONS-213: -- Would it make more sense to create an Iterable type that simply wraps an Iterator? That would eliminate the need to maintain additional versions of these methods. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Assignee: Brent Worden Fix For: 4.x Attachments: COLLECTIONS-213.patch, CollectionUtils.java, TestCollectionUtils.java, collections-4.0-213.diff I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen dusan.chr...@freenet.de wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] Commented: (COLLECTIONS-213) CollectionUtils API extension: algorithm methods accept an Iterator argument
[ https://issues.apache.org/jira/browse/COLLECTIONS-213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=12583809#action_12583809 ] Ryan Ovrevik commented on COLLECTIONS-213: -- Sorry for the delay in responding to the suggestion to close this feature request. Unless I am missing something, the functionality provided by creating an intermediate list is not sufficient for our use cases. We use iterators in a pipes and filters-based batch process. The iterators are backed by fifo queues that are populated from database records. Using the intermediate list approach would require that all items piped through the process would first be read into (and stay in) memory. CollectionUtils API extension: algorithm methods accept an Iterator argument Key: COLLECTIONS-213 URL: https://issues.apache.org/jira/browse/COLLECTIONS-213 Project: Commons Collections Issue Type: Improvement Components: Core Reporter: Dusan Chromy Fix For: 3.3 Attachments: CollectionUtils.java, TestCollectionUtils.java I just finished the Iterator additions to CollectionUtils, including test cases and I am going to attach them to this issue very shortly (basically as soon as I figure out how attaching in JIRA works :) At first I was thinking for a while whether CollectionUtils is a good place to accomodate the methods with the new signature, until I noticed the collect method already accepts an Iterator argument. Following methods now accept an Iterator argument (besides collect): cardinality find forAllDo countMatches exists I also noticed cardinality used to throw a NPE if the collection argument was null. I see no reason why it should not return zero. The Iterator flavour does return zero and I also modified the Collection version to return zero (including Javadoc modification) for the sake of consistence. I stopped to think for a while before touching the method, but the fact that the Javadoc does not mention may not be null made me think the NPE is not thrown intentionally. And after all, cardinality(..) is nothing else than specialized countMatches(..), which returns 0 for null collection. However, feel free to reject the change to the cardinality(Object,Collection) method if you think otherwise. I worked on a fresh checkout from subversion and I just updated few minutes ago to make sure I have modified the latest version. Anyway, please double-check before commiting the changes. Cheers, Dusan I think that these methods would make useful additions to the API. I don't have the time to do much collections work these days, but if you want to code the methods with test cases and attach them to JIRA then that would be great. Stephen [EMAIL PROTECTED] wrote: I've been using some algorithm methods from the CollectionUtils, for example find(Collection, Predicate) exists(Collection, Predicate) countMatches(Collection, Predicate) forAllDo(Collection, Closure) However, I would also like to be able to use these algorithms with an Iterator: find(Iterator, Predicate) exists(Iterator, Predicate) countMatches(Iterator, Predicate) forAllDo(Iterator, Closure) The obvious workaround is to use IteratorUtils.toList(Iterator), however this comes at the cost of constructing a list object (an ArrayList presumably) which could be avoided, as the Iterator itself is sufficient for the above algorithms to work. What do you think? Is there any reason not to provide the algorithms for an Iterator? I personally think that the algorithms should have been there for Iterators in the first place, because every collection is Iterable (or has an Iterator, prior to JDK 5.0). If noone is interested or has time to implement these changes, I can also contribute to the project - but at the moment I just wanted to discuss the idea / check if this has been already considered or planned. Best Regards, Dusan Chromy -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
