[stringtemplate-interest] handling of arrays
Harry Karadimas
harry.karadimas at hmn.aphp.fr
Thu Feb 1 09:24:26 PST 2007
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 :
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> 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
>
>
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