Howdy,
I've taken Matt's suggestion onboard and I have investigated DynaBeans.
These look pretty good for all intestive purposes and there's a code
examples below how to build the data structure:
+ root [...@name="ROOT"]
+ animal [...@name="ANIMAL"]
+ dog [...@name="DOG"]
+ boxer [...@name="BOXER"]
+ labrador [...@name="LABRADOR"]
+ cat [...@name="CAT"]
+ tiger [...@name="TIGER-ONE"]
+ tiger [...@name="TIGER-TWO"]
+ tiger [...@name="TIGER-THREE"]
+ lion [...@name="LION"]
And the code looks like...
LazyDynaBean lazyDynaBean = new LazyDynaBean(); //the transparent root.
LazyDynaBean root = new LazyDynaBean();
LazyDynaBean animal = new LazyDynaBean();
LazyDynaBean dog = new LazyDynaBean();
LazyDynaBean cat = new LazyDynaBean();
LazyDynaBean boxer = new LazyDynaBean();
LazyDynaBean labrador = new LazyDynaBean();
LazyDynaBean tiger1 = new LazyDynaBean();
LazyDynaBean tiger2 = new LazyDynaBean();
LazyDynaBean tiger3 = new LazyDynaBean();
LazyDynaBean lion = new LazyDynaBean();
//set the @name property of each bean, user UPPER to make them distinct for
examples.
root.set("name","ROOT");
animal.set("name","ANIMAL");
dog.set("name","DOG");
cat.set("name","CAT");
boxer.set("name","BOXER");
labrador.set("name","LABRADOR");
tiger1.set("name","TIGER-ONE");
tiger2.set("name","TIGER-TWO");
tiger3.set("name","TIGER-THREE");
lion.set("name","LION");
//build the bean hierarchy.
lazyDynaBean.set("root",0, root);
root.set("animal",0, animal);
animal.set("dog",0,dog);
animal.set("cat",0,cat);
dog.set("labrador",0,labrador);
dog.set("boxer",0, boxer);
cat.set("tiger",0,tiger1);//duplicate
cat.set("tiger",1,tiger2);//duplicate
cat.set("tiger",1,tiger3);//duplicate
cat.set("lion",0,lion);
JXPathContext context = JXPathContext.newContext(lazyDynaBean);
String query = "/root/animal/cat/tiger";
Object value = context.getValue(query);
But there's a problem with JXPath querying this also. Absolute Paths like
'/root/animal/cat/tiger' or '/root/animal/cat/tiger'[2]' work perfectly.
But I don't have anyluck doing "deep" searches. For examples the following
just won't work.
'//cat'
//*...@name='LION']
/root/animal/cat/tig...@name='TIGER-TWO']
Things are looking up, but is this behavior to be expected?
Cheers,
--AH
On Thu, Feb 12, 2009 at 6:43 AM, Matt Benson <gudnabr...@yahoo.com> wrote:
>
>
>
>
> --- On Wed, 2/11/09, Andrew Hughes <ahhug...@gmail.com> wrote:
>
> > From: Andrew Hughes <ahhug...@gmail.com>
> > Subject: Re: JXPath over Generic Collection<?>, How?
> > To: "Commons Users List" <user@commons.apache.org>
> > Date: Wednesday, February 11, 2009, 4:19 AM
> > Still No Luck, I have removed recursive generic collections
> > and have tried
> > the following code... this is becoming a marathon effort
> > :'(
> >
> > public class Thing {
> >
> > public Thing(String name) {
> > this.name = name;
> > }
> > private String name = "";
> >
> > public String getName() {
> > return name;
> > }
> > private ArrayList<Thing> children = new
> > ArrayList<Thing>();
> >
> > public ArrayList<Thing> getChildren() {
> > return children;
> > }
> >
> > }
> >
> >
> > public static void main(String[] args) {
> > //get some same data
> > Thing animal = new Thing("Animal");
> > //Animal.Dog.*
> > Thing dog = new Thing("Dog");
> > dog.getChildren().add(new
> > Thing("Labrador"));
> > dog.getChildren().add(new
> > Thing("Boxer"));
> > animal.getChildren().add(dog);
> > //Animal.Cat.*
> > Thing cat = new Thing("Cat");
> > cat.getChildren().add(new Thing("Lion"));
> > cat.getChildren().add(new
> > Thing("Tiger"));
> > animal.getChildren().add(cat);
> >
> > //run a query on it
> > JXPathContext context =
> > JXPathContext.newContext(animal);
> > String query = "/Animal";
> > Thing result = (Thing) context.getValue(query);
> > String path = context.getPointer(query).asPath();
> > System.out.println("Ran '" + query +
> > "' and got '" +
> > result.getName() + "' on path '" + path +
> > "'.");
> > }
> >
>
> What would you be trying to select? If you want to know how to look for a
> given Thing in this graph, I can probably help. If you want to know what
> graph will allow you to use a preconceived notion of the xpath you want to
> use, that will be harder. You might use [beanutils] dynabeans in
> conjunction with [jxpath] to try and achieve the latter.
>
> -Matt
>
> >
> >
> >
> > On Wed, Feb 11, 2009 at 3:08 PM, Andrew Hughes
> > <ahhug...@gmail.com> wrote:
> >
> > > Yeah, that makes sense. The part that was confusing me
> > is that if I
> > > have...
> > >
> > > public class Thing {
> > >
> > > private List<Thing> children;
> > >
> > > }
> > >
> > > I was assuming I would need to prefix all of my
> > expressions "steps" with
> > > '/children'. From what you said earlier this
> > is not the case as collections
> > > are "auto traversed/loaded".
> > >
> > > Thanks again matt! I won't get to test this out
> > til later tonight be look
> > > foward to seeing it working!!!
> > >
> > > Andrew
> > >
> > >
> > > On Wed, Feb 11, 2009 at 2:57 PM, Matt Benson
> > <gudnabr...@yahoo.com> wrote:
> > >
> > >>
> > >> It should be as simple as Thing _containing_ a
> > List<Thing> rather than
> > >> _being_ a List<Thing>. Composition over
> > inheritance, do you see?
> > >>
> > >> HTH,
> > >> Matt
> > >>
> > >>
> > >> --- On Tue, 2/10/09, Andrew Hughes
> > <ahhug...@gmail.com> wrote:
> > >>
> > >> > From: Andrew Hughes
> > <ahhug...@gmail.com>
> > >> > Subject: Re: JXPath over Generic
> > Collection<?>, How?
> > >> > To: "Commons Users List"
> > <user@commons.apache.org>,
> > >> gudnabr...@yahoo.com
> > >> > Date: Tuesday, February 10, 2009, 7:06 PM
> > >> > Matt, Thank You.
> > >> >
> > >> > Is there any other data structure I can use
> > that would work
> > >> > with JXPath? My
> > >> > requirement is that... a "Thing"
> > can have contain
> > >> > multiple child "Thing(s)"
> > >> > (and the children are allowed to be
> > non-unique).
> > >> > This is equivalent to an XML element as it
> > can contain
> > >> > multiple child
> > >> > elements, how do these guy's handle it I
> > wonder?
> > >> >
> > >> > --Andrew
> > >> >
> > >> >
> > >> > On Wed, Feb 11, 2009 at 9:09 AM, Matt Benson
> > >> > <gudnabr...@yahoo.com> wrote:
> > >> >
> > >> > >
> > >> > > I admit I hadn't looked at this with
> > a highly
> > >> > critical eye, but this
> > >> > > business of Thing extending
> > ArrayList<Thing>
> > >> > seems quite strange to me.
> > >> > > JXPath basically functions by
> > "opening up"
> > >> > collections automatically, so
> > >> > > the very fact that Thing is itself a
> > Collection
> > >> > implies that a Thing will be
> > >> > > opened up, and its children will be
> > searched... but in
> > >> > this example, either
> > >> > > there are no children, at the leaves, or
> > the children
> > >> > themselves are
> > >> > > (possibly empty) collections. It looks
> > as though
> > >> > you're trying to represent
> > >> > > a tree structure. This may be a good
> > example of a
> > >> > reason for the idea of
> > >> > > composition over inheritance. I
> > don't think
> > >> > you're going to get any
> > >> > > traction using JXPath with this object
> > model.
> > >> > >
> > >> > > Sorry for the bad news,
> > >> > > Matt
> > >> > >
> > >> > >
> > >> > > --- On Tue, 2/10/09, Andrew Hughes
> > >> > <ahhug...@gmail.com> wrote:
> > >> > >
> > >> > > > From: Andrew Hughes
> > <ahhug...@gmail.com>
> > >> > > > Subject: Re: JXPath over Generic
> > >> > Collection<?>, How?
> > >> > > > To: "Commons Users List"
> > >> > <user@commons.apache.org>
> > >> > > > Date: Tuesday, February 10, 2009,
> > 7:16 AM
> > >> > > > Still busted. Example is now
> > simplified. As soon
> > >> > as a
> > >> > > > generic Collection
> > >> > > > becomes involved BOOM!
> > >> > > >
> > >> > > > The Main Method to exec:
> > >> > > > public class App {
> > >> > > > public static void main(
> > String[] args ){
> > >> > > > JXPathContext context =
> > >> > > > JXPathContext.newContext(new
> > ThingRoot());
> > >> > > >
> > >> > > >
> > >> >
> > System.out.println(((Thing)context.getValue("/root")).getName());
> > >> > > > }
> > >> > > > }
> > >> > > >
> > >> > > > The (populated) context root I am
> > using, where
> > >> > root is a
> > >> > > > single object
> > >> > > > holding a List of Thing's.
> > >> > > > package jxpathresearch;
> > >> > > >
> > >> > > > import java.util.ArrayList;
> > >> > > > import java.util.List;
> > >> > > >
> > >> > > > public class ThingRoot {
> > >> > > > private List<Thing> root
> > new
> > >> > ArrayList(); //this
> > >> > > > will serve as the root.
> > >> > > > public ThingRoot() {
> > >> > > > Thing animal = new
> > >> > Thing("Animal");
> > >> > > > root.add(animal);//Animal
> > >> > > > Thing dog = new
> > Thing("Dog");
> > >> > > >
> > animal.add(dog);//Animal.Dog
> > >> > > > dog.add(new
> > >> > > >
> > >> >
> > Thing("Labrador"));//Animal.Dog.Labrador
> > >> > > > dog.add(new
> > >> > > >
> > Thing("Boxer"));//Animal.Dog.Boxer
> > >> > > > }
> > >> > > > public List<Thing>
> > getRoot() { return
> > >> > root; }
> > >> > > > }
> > >> > > >
> > >> > > > Finally here's a very simple
> > 'Thing'
> > >> > that
> > >> > > > contains a List of Thing(s):
> > >> > > > public class Thing extends
> > ArrayList<Thing>
> > >> > {
> > >> > > > public Thing(String
> > name){this.name = name;}
> > >> > > > private String name =
> > "";
> > >> > > > public String getName() {return
> > name;}
> > >> > > > }
> > >> > > >
> > >> > > > I can't query anything beyond
> > /root, it
> > >> > doesn't
> > >> > > > seem to ever get traversed.
> > >> > > > I would expect results for //Thing
> > and
> > >> > > > //thi...@name='Labrador']
> > etc but I
> > >> > > > get no results only exceptions.
> > >> > > >
> > >> > > >
> > >> > > > My brain is hurting.
> > >> > > >
> > >> > > >
> > >> > > >
> > >> > > > On Tue, Feb 10, 2009 at 12:22 AM,
> > Andrew Hughes
> > >> > > > <ahhug...@gmail.com> wrote:
> > >> > > >
> > >> > > > > I've noew tested a whole
> > heap of
> > >> > expressions even
> > >> > > > //name='Tiger' nothing
> > >> > > > > works.
> > >> > > > >
> > >> > > > > On Tue, Feb 10, 2009 at 12:01
> > AM, Andrew
> > >> > Hughes
> > >> > > > <ahhug...@gmail.com>wrote:
> > >> > > > >
> > >> > > > >> I got cracking on testing
> > this out... no
> > >> > luck
> > >> > > > (yet). Here's my testing
> > >> > > > >> code if some kind person
> > could please
> > >> > take a
> > >> > > > look....
> > >> > > > >> First my generic
> > collection hierarchy
> > >> > (which only
> > >> > > > contains a name and
> > >> > > > >> children)...
> > >> > > > >>
> > >> > > > >> package jxpathresearch;
> > >> > > > >>
> > >> > > > >> import
> > java.util.ArrayList;
> > >> > > > >>
> > >> > > > >> public class HierarchyPojo
> > extends
> > >> > > > ArrayList<HierarchyPojo> {
> > >> > > > >>
> > >> > > > >> public
> > HierarchyPojo(String name){
> > >> > > > >>
> > this.setName(name);
> > >> > > > >> }
> > >> > > > >> private String name =
> > "";
> > >> > > > >>
> > >> > > > >> public String
> > getName() {
> > >> > > > >> return name;
> > >> > > > >> }
> > >> > > > >> public void
> > setName(String name) {
> > >> > > > >> this.name = name;
> > >> > > > >> }
> > >> > > > >>
> > >> > > > >> }
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> Next, the wrapper for the
> > root context
> > >> > (as Matt
> > >> > > > suggested) and populated
> > >> > > > >> with animals...
> > >> > > > >>
> > >> > > > >> package jxpathresearch;
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> public class
> > CollectionRoot {
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> private HierarchyPojo
> > hierarchyPojo;
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> public
> > CollectionRoot(){
> > >> > > > >>
> > >> > > > >> //Animal
> > >> > > > >>
> > >> > > > >> hierarchyPojo =
> > new
> > >> > > > HierarchyPojo("Animal");
> > >> > > > >>
> > >> > > > >> //Animal.Dog
> > >> > > > >>
> > >> > > > >> HierarchyPojo dog
> > = new
> > >> > > > HierarchyPojo("Dog");
> > >> > > > >>
> > >> > > > >>
> > //Animal.Dog.Labrador
> > >> > > > >>
> > >> > > > >> dog.add(new
> > >> > > >
> > HierarchyPojo("Labrador"));
> > >> > > > >>
> > >> > > > >> //Animal.Dog.Boxer
> > >> > > > >>
> > >> > > > >> dog.add(new
> > >> > > > HierarchyPojo("Boxer"));
> > >> > > > >>
> > >> > > > >>
> > //Animal.Dog.Mastiff
> > >> > > > >>
> > >> > > > >> dog.add(new
> > >> > > >
> > HierarchyPojo("Mastiff"));
> > >> > > > >>
> > >> > > > >> //Animal.Cat
> > >> > > > >>
> > >> > > > >> HierarchyPojo cat
> > = new
> > >> > > > HierarchyPojo("Cat");
> > >> > > > >>
> > >> > > > >> //Animal.Cat.Tiger
> > >> > > > >>
> > >> > > > >> cat.add(new
> > >> > > > HierarchyPojo("Tiger"));
> > >> > > > >>
> > >> > > > >>
> > //Animal.Cat.Cougar
> > >> > > > >>
> > >> > > > >> cat.add(new
> > >> > > > HierarchyPojo("Cougar"));
> > >> > > > >>
> > >> > > > >>
> > //Animal.Cat.Leopard
> > >> > > > >>
> > >> > > > >> cat.add(new
> > >> > > >
> > HierarchyPojo("Leopard"));
> > >> > > > >>
> > >> > > > >> //Add Animal.Dog
> > &
> > >> > Animal.Cat
> > >> > > > >>
> > >> > > > >>
> > hierarchyPojo.add(dog);
> > >> > > > >>
> > >> > > > >>
> > hierarchyPojo.add(cat);
> > >> > > > >>
> > >> > > > >> }
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> public HierarchyPojo
> > >> > getHierarchyPojo()
> > >> > > > {return hierarchyPojo;}
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> public void
> > >> > setHierarchyPojo(HierarchyPojo
> > >> > > > hierarchyPojo)
> > >> > > > >> {this.hierarchyPojo =
> > hierarchyPojo;}
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> }
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> Finally invoke and test...
> > >> > > > >>
> > >> > > > >> public class App
> > >> > > > >>
> > >> > > > >> {
> > >> > > > >>
> > >> > > > >> public static void
> > main( String[]
> > >> > args )
> > >> > > > >>
> > >> > > > >> {
> > >> > > > >>
> > >> > > > >> JXPathContext
> > context =
> > >> > > > JXPathContext.newContext(new
> > >> > > > >> CollectionRoot());
> > >> > > > >>
> > >> > > > >> String query =
> > >> > > >
> > >> >
> > "//hierarchypo...@name='Tiger']";
> > >> > > > >>
> > >> > > > >> String fName =
> > >> > > > context.getValue(query).toString();
> > >> > > > >>
> > >> > > > >>
> > System.out.println("Ran
> > >> > > > '"+query+"' and
> > got
> > >> > > >
> > '"+fName+"'");
> > >> > > > >>
> > >> > > > >> }
> > >> > > > >>
> > >> > > > >> }
> > >> > > > >>
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> Above, should find one
> > entry for
> > >> > > > 'name=Tiger' but it does
> > not, I get an
> > >> > > > >> exception. This still
> > doesn't seem
> > >> > to traverse
> > >> > > > the Collection correctly. Any
> > >> > > > >> help would be most
> > welcome.
> > >> > > > >> Exception in thread
> > "main"
> > >> > > > >>
> > >> >
> > org.apache.commons.jxpath.JXPathNotFoundException:
> > >> > > > No value for xpath:
> > >> > > > >>
> > //hierarchypo...@name='Tiger']
> > >> > > > >>
> > >> > > > >> Thanks for reading,
> > >> > > > >> Andrew
> > >> > > > >>
> > >> > > > >>
> > >> > > > >>
> > >> > > > >> On Mon, Feb 9, 2009 at
> > 10:24 PM, Andrew
> > >> > Hughes
> > >> > > > <ahhug...@gmail.com>wrote:
> > >> > > > >>
> > >> > > > >>> Thanks Matt - I will
> > test this out
> > >> > tomorrow
> > >> > > > when I am back in the
> > >> > > > >>> office...
> > >> > > > >>>
> > >> > > > >>> Being constructive...
> > >> > > > >>> Surely this should at
> > least be a
> > >> > precondition
> > >> > > > check and throw a specific
> > >> > > > >>> exception if it's
> > not supported?
> > >> > > > >>> Thank You
> > >> > > > >>> --Andrew
> > >> > > > >>>
> > >> > > > >>>
> > >> > > > >>> On Mon, Feb 9, 2009 at
> > 2:27 PM, Matt
> > >> > Benson
> > >> > > > <gudnabr...@yahoo.com>wrote:
> > >> > > > >>>
> > >> > > > >>>>
> > >> > > > >>>> Most likely your
> > problem is not
> > >> > with
> > >> > > > generics, but simply with the fact
> > >> > > > >>>> that JXPath has a
> > hard time
> > >> > using a
> > >> > > > collection as its root. The
> > easiest
> > >> > > > >>>> workaround is to
> > use some parent
> > >> > object to
> > >> > > > hold a reference to your
> > >> > > > >>>> container.
> > >> > > > >>>>
> > >> > > > >>>> HTH,
> > >> > > > >>>> Matt
> > >> > > > >>>>
> > >> > > > >>>>
> > >> > > > >>>> --- On Sun,
> > 2/8/09, Andrew
> > >> > Hughes
> > >> > > > <ahhug...@gmail.com> wrote:
> > >> > > > >>>>
> > >> > > > >>>> > From: Andrew
> > Hughes
> > >> > > > <ahhug...@gmail.com>
> > >> > > > >>>> > Subject:
> > JXPath over
> > >> > Generic
> > >> > > > Collection<?>, How?
> > >> > > > >>>> > To:
> > "Commons Users
> > >> > List"
> > >> > > > <user@commons.apache.org>
> > >> > > > >>>> > Date: Sunday,
> > February 8,
> > >> > 2009, 5:09
> > >> > > > PM
> > >> > > > >>>> > Hi All,
> > >> > > > >>>> > Hopefully the
> > solution is
> > >> > as easy as
> > >> > > > the question. I would
> > >> > > > >>>> > like to
> > perform
> > >> > > > >>>> > evaluation on
> > a (very
> > >> > simple) generic
> > >> > > > collection... as you
> > >> > > > >>>> > can see below
> > >> > > > >>>> >
> > (HeirarchyPojo). I should
> > >> > be able to
> > >> > > > ask for a
> > >> > > > >>>> >
> > HeirarchyPojo's with
> > >> > > > >>>> >
> > name='Bill' or the
> > >> > 3rd
> > >> > > > Child... The problem is that
> > >> > > > >>>> > nothing ever
> > evaluate on
> > >> > > > >>>> > this data
> > structure.
> > >> > What's the
> > >> > > > deal with Generic
> > >> > > > >>>> > Collections
> > and JXPath?
> > >> > > > >>>> >
> > >> > > > >>>> > p.s this is
> > not in the
> > >> > userguide and
> > >> > > > would be a most
> > >> > > > >>>> > welcomed
> > addition (if
> > >> > > > >>>> > we can nut
> > this out with
> > >> > your help).
> > >> > > > >>>> >
> > >> > > > >>>> > Cheers.
> > >> > > > >>>> >
> > >> > > > >>>> >
> > >> > > > >>>> > package
> > xpath.and.generics;
> > >> > > > >>>> >
> > >> > > > >>>> > import
> > java.util.ArrayList;
> > >> > > > >>>> >
> > >> > > > >>>> > public class
> > HeirarchyPojo
> > >> > extends
> > >> > > > >>>> >
> > >> > ArrayList<HeirarchyPojo>{
> > >> > > > >>>> >
> > >> > > > >>>> > public
> > >> > HeirarchyPojo(){}
> > >> > > > >>>> >
> > >> > > > >>>> > private
> > String id;
> > >> > > > >>>> > private
> > String name;
> > >> > > > >>>> >
> > >> > > > >>>> > public
> > String getId() {
> > >> > > > >>>> >
> > return id;
> > >> > > > >>>> > }
> > >> > > > >>>> >
> > >> > > > >>>> > public
> > void
> > >> > setId(String id) {
> > >> > > > >>>> >
> > this.id = id;
> > >> > > > >>>> > }
> > >> > > > >>>> >
> > >> > > > >>>> > public
> > String getName()
> > >> > {
> > >> > > > >>>> >
> > return name;
> > >> > > > >>>> > }
> > >> > > > >>>> >
> > >> > > > >>>> > public
> > void
> > >> > setName(String name)
> > >> > > > {
> > >> > > > >>>> >
> > this.name = name;
> > >> > > > >>>> > }
> > >> > > > >>>> >
> > >> > > > >>>> > }
> > >> > > > >>>>
> > >> > > > >>>>
> > >> > > > >>>>
> > >> > > > >>>>
> > >> > > > >>>>
> > >> > > >
> > >> >
> > ---------------------------------------------------------------------
> > >> > > > >>>> To unsubscribe,
> > e-mail:
> > >> > > > user-unsubscr...@commons.apache.org
> > >> > > > >>>> For additional
> > commands, e-mail:
> > >> > > > user-h...@commons.apache.org
> > >> > > > >>>>
> > >> > > > >>>>
> > >> > > > >>>
> > >> > > > >>
> > >> > > > >
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