[stringtemplate-interest] handling of arrays
Nate
misc at n4te.com
Thu Feb 1 12:22:38 PST 2007
That was in Eclipse with the compiler compliance level set to 1.4, so it
should work in 1.4. It should work in the same way as...
String string = "abc";
Object stringHiddenByObject = string;
What compiler error did you get?
-Nate
Terence Parr wrote:
> is that in java 1.5? I don't it will work in 1.4.
>
> my compiler complained.
>
> ter
>
> On Feb 1, 2007, at 12:18 PM, Nate wrote:
>
>> It does work, I was wrong. In fact, you don't even need a cast...
>>
>> String[] strings = new String[] {"abc", "def", "ghi"};
>> Object[] stringsHiddenByObjectArray = strings;
>>
>> What I was thinking of was going the other way...
>>
>> Object[] objects = new Object[] {"jkl", "mno", "pqr"};
>> String[] thisDoesntWork = (String[])objects;
>>
>> -Nate
>>
>>
>> Harry Karadimas wrote:
>>> Sorry about the lengthy post, but I checked and found that the cast to
>>> (Object[])
>>> actually works !
>>>
>>> Below is a "small" demo class that demonstrates various uses.
>>> To make it short, what works is :
>>> public static Object convertArrayToList(Object value)
>>> {
>>> if (value==null || !value.getClass().isArray()) return value;
>>> return Arrays.asList((Object[])value);
>>> }
>>>
>>> --------
>>>
>>> package stringtemplate_test;
>>>
>>> import java.util.ArrayList;
>>> import java.util.Arrays;
>>> import java.util.Collection;
>>> import java.util.Iterator;
>>> import java.util.List;
>>>
>>> /**
>>> * "Lots of Lists", to test various Array to List conversion strategies
>>> * @author KARADIMAS
>>> */
>>> public class Lol
>>> {
>>> static Object[] myArray = {"A", "B", "C"};
>>> static List myList = new ArrayList();
>>> static Object[][][] threeLevels = {
>>> {
>>> {"1.1.1", "1.1.2", "1.1.3"},
>>> {"1.2.1", "1.2.2"}
>>> },
>>> {
>>> {"2.1.1"},
>>> {"2.2.1", "2.2.2"}
>>> },
>>> {
>>> {"3.1.1", "3.1.2"},
>>> {"3.2.1"}
>>> },
>>> {
>>> {myList}
>>> },
>>> };
>>> static int[] myInts = {1,2,3};
>>>
>>> public static void main(String[] args)
>>> {
>>> //further init of myList
>>> myList.add("X");
>>> myList.add(myArray);
>>> myList.add("Z");
>>> System.out.println("Original list :");
>>> printList(threeLevels);
>>> System.out.println("convertArrayToList1() :");
>>> Object r = convertArrayToList1(threeLevels);
>>> printList((List) r);
>>> System.out.println("convertArrayToList2() :");
>>> r = convertArrayToList2(threeLevels);
>>> printList((List) r);
>>> System.out.println("convertAllForStUsage() :");
>>> r = convertAllAtOnce(threeLevels);
>>> printList((List) r);
>>> r = convertArrayToList1(myInts);
>>> printList(r);
>>> }
>>>
>>> /**
>>> * simplest, works ok if called before each use, maybe the best
>>> approach if
>>> * used in lazy (= just in time) execution.
>>> * Note here that Object[][]...[] is an instance of Object[] (and of
>>> * Object, incidentally)
>>> */
>>> public static Object convertArrayToList1(Object value)
>>> {
>>> if (value==null || !value.getClass().isArray()) return value;
>>> return Arrays.asList((Object[])value);
>>> }
>>>
>>> /**
>>> * handles sub-arrays recursively at once, but what about arrays
>>> inside lists?
>>> */
>>> public static Object convertArrayToList2(Object value)
>>> {
>>> if (value==null || !value.getClass().isArray()) return value;
>>> Object[] oa1 = (Object[]) value;
>>> Object[] oa2 = new Object[oa1.length];
>>> System.arraycopy(oa1, 0, oa2, 0, oa1.length);
>>> for (int i = 0; i < oa2.length; i++) oa2[i] =
>>> convertArrayToList2(oa2[i]);
>>> return Arrays.asList(oa2);
>>> }
>>>
>>> /**
>>> * More complex method.
>>> * Manages both lists and arrays, but what about arrays inside
>>> maps, for
>>> * example ? And also, why convert now arrays that might never be
>>> used ?
>>> */
>>> public static Object convertAllAtOnce(Object value)
>>> {
>>> if ( !isListable(value) ) return value;
>>> ArrayList res = new ArrayList(); //we always return a new list
>>> if (value instanceof List) {
>>> //process the list
>>> List vList = (List) value;
>>> for (Iterator iter = vList.iterator(); iter.hasNext();) {
>>> res.add(convertAllAtOnce(iter.next()));
>>> }
>>> return res;
>>> }
>>> //it's an array, process its elements
>>> Object[] oa = (Object[]) value;
>>> for (int i = 0; i < oa.length; i++)
>>> res.add(convertAllAtOnce(oa[i]));
>>> return res;
>>> }
>>>
>>> /** helper function to clarify code */
>>> private static final boolean isListable(Object o)
>>> {
>>> return (o instanceof List) || (o != null &&
>>> o.getClass().isArray());
>>> }
>>>
>>> public static void printList(Object v) { printList("", v); }
>>>
>>> public static void printList(String indent, Object v) {
>>> if (!isListable(v)) {
>>> System.out.println(indent+"v="+v);
>>> return;
>>> }
>>> if (v instanceof List) {
>>> System.out.println(indent+"(");
>>> List lst = (List) v;
>>> for (Iterator iter = lst.iterator(); iter.hasNext();) {
>>> Object o = (Object) iter.next();
>>> printList(indent+" ", o);
>>> }
>>> System.out.println(indent+")");
>>> return;
>>> }
>>> Object[] oa = (Object[]) v;
>>> System.out.println(indent+"[//array");
>>> for (int i = 0; i < oa.length; i++) printList(indent+" ", oa[i]);
>>> System.out.println(indent+"]//array");
>>> }
>>>
>>> }
>>>
>>> Harry Karadimas
>>> /______________________________________________________________________
>>> Dr Harry Karadimas Medecin Ingenieur resp. Recherche et Developpement
>>> Departement d'Information Hospitalier
>>> CHU Henri Mondor 51, av. du Mal de Lattre de Tassigny 94010 CRETEIL
>>> tel : (00 33 1) 49 81 21 79 fax : (00 33 1) 49 81 27 08
>>> secr.: (00 33 1) 49 81 23 82 m.el.:harry.karadimas at hmn.ap-hop-paris.fr
>>> /
>>>
>>>
>>> stringtemplate-interest-request at antlr.org a écrit :
>>>> Send stringtemplate-interest mailing list submissions to
>>>> stringtemplate-interest at antlr.org
>>>>
>>>> To subscribe or unsubscribe via the World Wide Web, visit
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>>>> or, via email, send a message with subject or body 'help' to
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>>>>
>>>> When replying, please edit your Subject line so it is more specific
>>>> than "Re: Contents of stringtemplate-interest digest..."
>>>>
>>>>
>>>> Today's Topics:
>>>>
>>>> 1. Re: handling of arrays (John Snyders) (Terence Parr)
>>>> 2. Re: handling of arrays (John Snyders) (Terence Parr)
>>>> 3. Re: Porting StringTemplate (Kay Roepke)
>>>>
>>>>
>>>> ----------------------------------------------------------------------
>>>>
>>>> Message: 1
>>>> Date: Tue, 30 Jan 2007 12:14:43 -0800
>>>> From: Terence Parr <parrt at cs.usfca.edu>
>>>> Subject: Re: [stringtemplate-interest] handling of arrays (John
>>>> Snyders)
>>>> To: Nate <misc at n4te.com>
>>>> Cc: StringTemplate <stringtemplate-interest at antlr.org>
>>>> Message-ID: <E02F2DC0-7AE7-4B2B-A69A-49E19AD2CCE8 at cs.usfca.edu>
>>>> Content-Type: text/plain; charset=ISO-8859-1; delsp=yes; format=flowed
>>>>
>>>> crap. Ok, back to arrayiterator then.
>>>> Ter
>>>> On Jan 30, 2007, at 11:54 AM, Nate wrote:
>>>>
>>>>
>>>>> Unless you are using Java 5+, you'd have to use System.arrayCopy to
>>>>> copy the array to an Object array.
>>>>>
>>>>> -Nate
>>>>>
>>>>>
>>>>> Terence Parr wrote:
>>>>>
>>>>>> Awesome! Heh, it's exactly what we want I think.
>>>>>>
>>>>>> Wait, class cast issue:
>>>>>>
>>>>>> public static Object convertArrayToList(Object value) {
>>>>>> if ( value==null ) {
>>>>>> return null;
>>>>>> }
>>>>>> if ( value.getClass().isArray() ) {
>>>>>> return Arrays.asList((Object[])value); // CAST ISSUE!
>>>>>> }
>>>>>> return value;
>>>>>> }
>>>>>>
>>>>>> won't work as value is not Object[] most of the time...but how do
>>>>>> you get it to compile w/o the cast?
>>>>>>
>>>>>> Ter
>>>>>>
>>>>>> On Jan 30, 2007, at 9:13 AM, Harry Karadimas wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Hi, I don't know if that relates to the previous post, but java
>>>>>>> *does* have something
>>>>>>> to encapsulate an array into a list, and that is the "asList"
>>>>>>> method of the java.util.Arrays
>>>>>>> class.
>>>>>>>
>>>>>>> Object[] myArray = ...
>>>>>>> List myList = Arrays.asList(myArray);
>>>>>>>
>>>>>>> Harry Karadimas
>>>>>>> ____________________________________________________________________
>>>>>>>
>>>>>>> __ Dr Harry Karadimas Medecin Ingenieur resp. Recherche et
>>>>>>> Developpement Departement d'Information Hospitalier CHU Henri
>>>>>>> Mondor 51, av. du Mal de Lattre de Tassigny 94010 CRETEIL tel :
>>>>>>> (00 33 1) 49 81 21 79 fax : (00 33 1) 49 81 27 08 secr.: (00 33
>>>>>>> 1) 49 81 23 82 m.el.:harry.karadimas at hmn.ap-hop-paris.fr
>>>>>>>
>>>>>>>
>>>>>>> stringtemplate-interest-request at antlr.org a ?crit :
>>>>>>>
>>>>>>>
>>>>>>>> Send stringtemplate-interest mailing list submissions to
>>>>>>>> stringtemplate-interest at antlr.org To subscribe or unsubscribe
>>>>>>>> via the World Wide Web, visit http://www.antlr.org:8080/
>>>>>>>> mailman/ listinfo/stringtemplate-interest or, via email, send a
>>>>>>>> message with subject or body 'help' to stringtemplate-interest-
>>>>>>>> request at antlr.org You can reach the person managing the list at
>>>>>>>> stringtemplate-interest-owner at antlr.org When replying, please
>>>>>>>> edit your Subject line so it is more specific than "Re:
>>>>>>>> Contents of stringtemplate-interest digest..." Today's Topics:
>>>>>>>> 1. Re: handling of arrays (John Snyders) 2. Re: inconsistency
>>>>>>>> with length function (Oliver Flege)
>>>>>>>> -------------------------------------------------------------------
>>>>>>>>
>>>>>>>> -- - Message: 1 Date: Sun, 28 Jan 2007 21:44:26 -0500 From:
>>>>>>>> "John Snyders" <jjsnyders at rcn.com> Subject: Re:
>>>>>>>> [stringtemplate- interest] handling of arrays To: "Terence
>>>>>>>> Parr" <parrt at cs.usfca.edu>, "StringTemplate" <stringtemplate-
>>>>>>>> interest at antlr.org> Message-ID:
>>>>>>>> <PMEOJKDLMMHOHNEAMPBGGEJMCAAA.jjsnyders at rcn.com> Content-Type:
>>>>>>>> text/plain; charset="US-ASCII"
>>>>>>>>
>>>>>>>>
>>>>>>>>> -----Original Message----- From: stringtemplate-interest-
>>>>>>>>> bounces at antlr.org [mailto:stringtemplate-interest-
>>>>>>>>> bounces at antlr.org]On Behalf Of Terence Parr Sent: Saturday,
>>>>>>>>> January 27, 2007 6:38 PM To: StringTemplate Subject: Re:
>>>>>>>>> [stringtemplate-interest] handling of arrays On Jan 16, 2007,
>>>>>>>>> at 9:40 PM, John Snyders wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> I noticed in ASTExpr.java the method convertArrayToList.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> it is. just done to make things consistent...else have to
>>>>>>>>> check for arrays everyone. gross, eh?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> It seems to me that this is wasteful. I have not looked at it
>>>>>>>>>> too deep but why not handle arrays like other collections and
>>>>>>>>>> wrap them in an ArrayIterator inside
>>>>>>>>>> convertAnythingIteratableToIterator.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> Interesting...ArrayIterator, eh? Does Sun have a standard one?
>>>>>>>>> I don't see it. Do you mean I should create one real quick?
>>>>>>>>>
>>>>>>>>>
>>>>>>>> There isn't one in the Java SDK (as far as I know) but jakarta
>>>>>>>> commons has one http://jakarta.apache.org/commons/collections/
>>>>>>>> api- release/org/apache/commons /collections/iterators/
>>>>>>>> ArrayIterator.html ST probably shouldn't rely on this so you
>>>>>>>> can create your own. It is straight forward. I created one
>>>>>>>> before I found the one in commons collections. I can give it to
>>>>>>>> you if you like (assuming I can find it). But again I didn't
>>>>>>>> think this through fully.
>>>>>>>>
>>>>>>>>
>>>>>>>>> Ter _______________________________________________
>>>>>>>>> stringtemplate-interest mailing list stringtemplate-
>>>>>>>>> interest at antlr.org http://www.antlr.org:8080/mailman/listinfo/
>>>>>>>>> stringtemplate-interest
>>>>>>>>>
>>>>>>>>>
>>>>>>>> ------------------------------ Message: 2 Date: Mon, 29 Jan
>>>>>>>> 2007 10:25:24 +0100 From: Oliver Flege <o.flege at market-
>>>>>>>> maker.de> Subject: Re: [stringtemplate-interest] inconsistency
>>>>>>>> with length function To: StringTemplate <stringtemplate-
>>>>>>>> interest at antlr.org> Message-ID: <45BDBD84.4040707 at market-
>>>>>>>> maker.de> Content-Type: text/ plain; charset=ISO-8859-1 Hi,
>>>>>>>> Terence Parr wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>>> I think that the length method in ASTExpr.java should be
>>>>>>>>>> changed as follows: From: } else if (attribute instanceof
>>>>>>>>>> List) { i = ((List)attribute).size(); } To: } else if
>>>>>>>>>> (attribute instanceof Collection) { i = ((List)attribute).size
>>>>>>>>>> (); }
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> Howdy! OK, yep, good fix.
>>>>>>>>>
>>>>>>>>>
>>>>>>>> even better would be } else if (attribute instanceof
>>>>>>>> Collection) { i = ((Collection)attribute).size(); } :) Cheers,
>>>>>>>> Oliver ------------------------------
>>>>>>>> _______________________________________________ stringtemplate-
>>>>>>>> interest mailing list stringtemplate-interest at antlr.org http://
>>>>>>>> www.antlr.org:8080/mailman/listinfo/stringtemplate-interest End
>>>>>>>> of stringtemplate-interest Digest, Vol 22, Issue 14
>>>>>>>> *******************************************************
>>>>>>>>
>>>>>>>>
>>>>>>> <harry.karadimas.vcf>
>>>>>>> _______________________________________________
>>>>>>> stringtemplate-interest mailing list
>>>>>>> stringtemplate-interest at antlr.org
>>>>>>> http://www.antlr.org:8080/mailman/listinfo/stringtemplate-interest
>>>>>>>
>>>>>>>
>>>>>> _______________________________________________
>>>>>> stringtemplate-interest mailing list
>>>>>> stringtemplate-interest at antlr.org
>>>>>> http://www.antlr.org:8080/mailman/listinfo/stringtemplate-interest
>>>>>>
>>>>>>
>>>>
>>>>
>>>>
>>>> ------------------------------
>>>>
>>>> Message: 2
>>>> Date: Tue, 30 Jan 2007 13:13:24 -0800
>>>> From: Terence Parr <parrt at cs.usfca.edu>
>>>> Subject: Re: [stringtemplate-interest] handling of arrays (John
>>>> Snyders)
>>>> To: StringTemplate <stringtemplate-interest at antlr.org>
>>>> Message-ID: <5DE29967-5C4B-4700-8D51-EDB9CF147D51 at cs.usfca.edu>
>>>> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>>>>
>>>> Ok, i made an array wrapper and iterator. had to do both so a list
>>>> is not purely an iterator, which has sideeffects.
>>>>
>>>> /** Do a standard conversion of array attributes to a List.
>>>> Wrap the
>>>> * array instead of copying like old version. Make an
>>>> * ArrayWrappedInList that knows to create an ArrayIterator.
>>>> */
>>>> public static Object convertArrayToList(Object value) {
>>>> if ( value==null ) {
>>>> return null;
>>>> }
>>>> if ( value.getClass().isArray() ) {
>>>> return new ArrayWrappedInList(value);
>>>> }
>>>> return value;
>>>> }
>>>>
>>>> ArrayWrappedInList creates ArrayIterator. These are two new classes.
>>>>
>>>> Pushed to depot.
>>>>
>>>> Ter
>>>>
>>>> On Jan 30, 2007, at 9:13 AM, Harry Karadimas wrote:
>>>>
>>>>
>>>>> Hi, I don't know if that relates to the previous post, but java
>>>>> *does* have something
>>>>> to encapsulate an array into a list, and that is the "asList"
>>>>> method of the java.util.Arrays
>>>>> class.
>>>>>
>>>>> Object[] myArray = ...
>>>>> List myList = Arrays.asList(myArray);
>>>>>
>>>>> Harry Karadimas ____
>>>>>
>>>>
>>>>
>>>> ------------------------------
>>>>
>>>> Message: 3
>>>> Date: Wed, 31 Jan 2007 02:21:11 +0100
>>>> From: Kay Roepke <kroepke at classdump.org>
>>>> Subject: Re: [stringtemplate-interest] Porting StringTemplate
>>>> To: Shane Witbeck <shane at digitalsanctum.com>
>>>> Cc: StringTemplate <stringtemplate-interest at antlr.org>
>>>> Message-ID: <6789A417-4627-450E-A443-BF753E93862F at classdump.org>
>>>> Content-Type: text/plain; charset=windows-1252; delsp=yes;
>>>> format=flowed
>>>>
>>>>
>>>> On Jan 28, 2007, at 1:04 AM, Shane Witbeck wrote:
>>>>
>>>>
>>>>> It seems like porting to ECMAScript would be better strategically
>>>>> since ActionScript is an extension of it and the amount of work out
>>>>> there being done in JavaScript (AJAX, etc.).
>>>>>
>>>>> Shane
>>>>>
>>>>> On 1/27/07, Terence Parr <parrt at cs.usfca.edu> wrote:
>>>>>
>>>>>> This would be very involved and a huge project. ANTLR doesn't
>>>>>> generate ActionScript so you'd need to parse everything by hand.
>>>>>>
>>>>>>
>>>>
>>>> Porting StringTemplate isn't exactly easy, esp. since it uses ANTLR
>>>> v2. My attempts
>>>> to do an Obj-C port haven't been exactly successful, mainly because
>>>> ANTLR v3 threw
>>>> up parsing ST :(
>>>>
>>>> I don't think that parsing ST by hand is a viable option, since it is
>>>> a bit involved
>>>> at times. I certainly wouldn't attempt it unless I was desperate...
>>>> In the long run, though, v3 should be able to handle ST easily and
>>>> that would make
>>>> it a lot easier (even if you'd need to write a new v3 target).
>>>>
>>>> As to the ECMAScript target, I'm not sure whether the current engines
>>>> are really fit to
>>>> do recursive descent parsing in. All the engines I have seen have
>>>> some real issues in
>>>> regard to memory, ie. tend to be slow molasses (but I admit it would
>>>> a cool thing to have
>>>> now and then).
>>>>
>>>> my 0.02?,
>>>>
>>>> -k
>>>>
>>>>
>>> _______________________________________________
>>> stringtemplate-interest mailing list
>>> stringtemplate-interest at antlr.org
>>> http://www.antlr.org:8080/mailman/listinfo/stringtemplate-interest
>>>
>>
>> _______________________________________________
>> stringtemplate-interest mailing list
>> stringtemplate-interest at antlr.org
>> http://www.antlr.org:8080/mailman/listinfo/stringtemplate-interest
>
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