So here are some photos from Luna’s first hunt test season.

First hunt test.. no ribbons.. lots to learn

Yay! we qualified!

Thurmont brought double ribbons! one more to go!

Midland test brought the title home..

We started her hunt tests around 9 months as that’s just what age she happened to be when the season rolled in. Training was done at the breeder’s (http://dynatavizslas.com/) house, she coached me through things but I was the handler in all hunt tests. It took 6 hunts tests but we managed to get her AKC Junior Hunter title in her first season.

I want to share a little about the last test.. I couldn’t have ended on a better note in my opinion. I went into this last test wanting to just let her do her thing. I went in with a goal of not talking to her, and just letting her go.  It was a decent day, sunny, not overly cold, and I liked the judges.  Luna found a bird early along the treeline that flanked the field we released them into. She held a real nice point, I produced the bird and capped off and we carried on. We started into the “woods” and she started finding birds left and right. We got into a pattern of, point, flush, cap, move on. There was a point early on where a bird had flushed over a barb wire fence and the judges kept fussing at me to get her away from there, so I finally broke down and verbally called her away. One of the reasons they were on my case so much was because a dog had just come out of the field with a bloodied tail (though they didn’t know from what). Anyway, I think I capped off about 5 times, and she found more birds than that. And the whole time (outside of the fence issue) I didn’t talk to her, just kept up with her and let her do her thing. There came a point where the judges told me to try and keep her away from the other dog to give that dog a chance.. It didn’t help that the dog was seriously gun shy and didn’t want to leave its owners side. Luna was a bird finding machine, I was so proud of her, and even slightly proud of myself for being able to keep my mouth shut and just watch what she can do.  We qualified with very high scores that day, all 9’s and 10’s.. a very good day.

Anyway, that’s the hunt test info in a nutshell.. Now time to make both our beds and get some sleep.

It was one of those mornings when toast and a cup of tea seemed far more appealing than taking the dogs out, not only on account of the drizzle but the fact that I could see the cloud base at about 1000 feet, meaning that visibility on the moor would be down to a few metres.  Nevertheless we headed for the hill.  What I couldn’t see from the windows of my house is that we had had some snow in the night above about 1200 feet as this was obscured by the low cloud.  It was cold.

Both dogs ran quite well, although it was difficult seeing either of them in the heather dappled with snow.  Before long Grace came on point.  It was a very solid point which was clearly backed by Archie who was following close behind.  I stood to take a photo before finding out that the camera memory card was full.  I then stood there in the drizzle and deleted photo after photo.  I must have stood there for a good five minutes before I was ready to move.  Both dogs duly stood there unwavering although this can’t have been comfortable for Archie who had backed in a now characteristic semi-dropped position.  The lens on the camera got wet, hence the blur.

When I was ready to move the dogs forwards something odd happened.  Grace moved forward form what was a solid point, flagged her tail rapidly, sniffed the ground then moved to the right as if to say ‘nothing here – just ground scent’.  She is usually right so I was surprised when Archie moved ahead and went on point, and even more surprised when a hen pheasant flushed from what must have been inches from the position Grace’s nose had been in earlier.  The bird rose and wheeled round over Grace’s head.  I blew the whistle, Archie dropped into a sit position and Grace chased the bird for a couple of metres before realising that this was futile.  We then carried on.

It wasn’t a bad session in that we had found game, but Grace is usually so accurate with her interpretation of scent this puzzled me.  Maybe it was the snow, who knows.

So these are some lucky shots.. due to the fact that the next day, I went to my parents land and they had bush hogged (aka, mowed down) all the long grass/bush/pricker/weed growth.. So no more exploring through the “brush”

Luna had a blast though, here are a couple shots.

Here is her "fake pointing" the songbirds in the garden.. wish I had it at a different angle.. might be more convincing

Love this shot.. so natural/rustic...

She blends right in.. don't know which version of this shot I like better..

Enjoy, I’m off to pack for my parents again.. today we hike to the river. Luna could use the exercise and mental stimulation hiking always brings. Looking forward to it greatly. hopefully will provide for some nice shots too.

[Sprite_tm] has whipped up yet another interesting tutorial – software-based this time. He basically describes how he connected his Wiimotes to an HTPC. A USB Bluetooth receiver, and a little bit of Linux scripting,  was all that was necessary to get the system up and running. To add to the fun, [Sprite_tm] configured a the controllers to work with MAME (an arcade machine emulator), allowing one to play Duck Hunt on a computer in its full glory!

It has suddenly become colder.  The weather has been very mild and wet for so long now that cold weather came as a bit of a shock…we may have snow on the way, at least it feels that way.

I took both Grace and Archie up to the racecourse for some exercise as much as anything else.  They both took it upon themselves to leap on top of one another and I didn’t try to stop them and turn this into a formal training session.  Archie has the edge on Grace now so only now and again does Grace make a break for it and try to out run him.  It’s only a bit of fun but it does give me the chance to see both dogs in full flight and get a feel for their mechanics and differences in conformation.  The pictures showing them side-on I find interesting.  Grace’s croup is more sloping setting her tail a bit lower, and Archie has muscle in places where Grace doesn’t.  This may be down to the sex difference I am not sure but they both run differently.  Archie pounds the ground as he charges from one place to another in a very powerful looking way, Grace however, looks to take it all in her stride, moving rather appropriately in a very graceful manner.  How much of this is down to differences ini conformation I don’t know, but it is interesting (to me at least).

I never miss an opportunity to drop the dogs to either a flushing bird or a shot.  In a field adjacent to the racecourse someone fired a shotgun soon after we had walked by.  Both dogs swung around and I dropped them both, with Grace sitting rather than dropping…although to be fair she did this instantaneously following the shot, rather than responding to any command I had given.

Ok, so now it was Archie’s turn.  We headed up onto the heather between short, sharp rain showers to find the whole area waterlogged.  It is hardly a surprise really as we have had 245mm of rain so far this month, but it seemed to be all in the same place this morning – a great deal of which found its way into my boots.

As we stepped onto the moor it was clear that we had a tailwind, so the only option was to walk alongside the moorland until we had reached a reasonable spot, then work Archie back into the wind and back towards the car.  This bit was fine.  When we reached a suitable spot I set Archie up then cast him off.  He went out to the left about 20 yards before pulling forwards into the wind and heading away from me.  I dropped him, called him back and repeated the whole thing in an effort to get it right.  Eventually he did get it right, charging out to the left about 100 yards before I turned him on the whistle.  He then came across me, but not quite, veering diagonally out away from me.  I dropped him, called him back and recast him, this time to the right.  He did this consistently until all it took was a clear ‘no’ for him to drop rather than a whistle or command of ’sit’.  I wasn’t really sure what he was thinking this morning as he seemed quite wild.  I knelt down in the heather to get a feel for the wind direction at his head height but it seemed as if I had got it right.  In the end I thought well, go on, have a blast and go where you want.  I will watch to see if a pattern develops and I have got it wrong.  So, off he went.

He pulled forward on scent a little way ahead, then pointed before a damp flush.  I walked up to him and encouraged him forwards.  as I did two hen pheasants got up on from the far side of the wet flush (arrowed).  I blew the whistle to drop Archie but I do believe he dropped to the flush, not the whistle.  I don’t think I imagined this.  I was really happy…as indeed was Archie who when cast off again ran like a dog possessed. The only odd thing now was that he ran very flat and completely at right angles to the wind with no correction from me.  I have no idea why this might have been and no idea why he pulled forwards earlier on.  He was too far away from these birds to have picked them up and showed no sign of picking up their scent until quite a bit later. 

We then covered the last bit of ground back to the car, including a large patch of rush, but no more birds.  I was very happy.  The second to last photo is a close-up of Archie charging towards me.  He is really starting to look quite fit…even with the cartoon ears.

I am taking some annual leave at the moment, giving more time than usual to work with the dogs, and I am doing my hardest to make the best of it.  I took both dogs out separately again today.  Grace was the first to get a run, only this time she was firmly attached to a lunge line and I was determined to make sure that she did what I wanted.  We went down by the river.  I love this part of the valley, it’s so different to the moorland on the top with the two landscapes contrasting dramatically with each other. 

I often wonder, walking down here, how much of the adult there is in the child, or conversely how much of the child remains in the adult.  I have said before but there are a few books I read as a child that I would consider formative, one being My Side of the Mountain by Jean George, a book about a boy who ran away to the Catskill Mountains, and the other being The Little Grey Men by BB.  I cannot help but think of both books as I walk here and it takes me right back to childhood.  I wonder how much our childhood influences where we live as adults.

Anyway, with Grace attached to the lunge line we left the car and headed for the gate into the woods.  I made sure that Grace didn’t put a foot forwards without being told to do so.  So far so good.  Soon after I let her ‘get on’ I dropped her on the whistle.  She dropped ok, but it wasn’t quick.  The stop was ok, but the ’settle’ down into the dropped position wasn’t quick or positive enough so we kept practising until she got it right, which she eventually did.  I then let her have a good run, still trailing the line.  She turned and recalled every time without a problem.

I then set her up on a patch of grassland, walked away and at a reasonable distance recalled her, stopping her before she got to me.  She did ok, her recall was good, she stopped ok,  but her drop was a ‘hup’ rather than a drop.  I walked towards her and put her in the right position.  We can practise this one again.  The rest of the session was spent investigating the river bank and an old quarry that has, in the past, held woodcock.  Nothing today, but the cold weather that is promised may push them a little further to the west.

Grace did fine and we had a good walk.

North Star

If we look at the stars, and then look again an hour or so later, we see that the spinning of the earth makes all the stars but the North Star seems to change positions in the sky.

The North Star does not appear to move because it lies almost directly over the North Pole, on tip of the earth’s axis, on which the earth spins.

Also called the polestar, its real name is Polaris. 

It is a possible to tell directions by the North Star.  When you point to it, you are pointing very nearly true north.

To find the North Star, first look for a group of seven bright stars that form the outline of long-handled cup.

This group is called the Big Dipper.  The two “pointer” stars in the front of the cup point to the North Star.  When you have found the North Star, look for the Little dipper.  The North Star is the last star in the Little Dipper’s handle.

Polaris will not always be the North Star.  Little by little the earth’s axis changes its direction.  After many centuries, the North Pole will be pointing to the star Vega, which will then become our North Star.

Visual source:  indepthinfo

I am beginning to suspect that Archie’s misbehaviour is inversely proportional to Grace’s, given the misbehaving that Grace got up to today and the sterling performance that Archie gave me (well, judged against my standards).  I took both dogs out separately today.  Archie up onto the heather and Grace down by the river.

I walked Archie up onto the heather face on into a stiff north wind.  Stiff really wasn’t the word as it was actually difficult to breath at times.  We went to a rather predictable area, in that the heather is good for running and the grouse are usually somewhere to be found.  I cast him off to the left and he ran flat, turned him on the brow of the ridge that ran south-north and brought him back across me.  His quartering today was excellent.  He was really on the ball with the whistle and ran very flat consistently.  This patch of moorland has the advantage of having a footpath that runs up the middle of it, meaning I can work the dog across me, without having to stride my way through heather.  It’s a bit of a luxury really.  Anyway, as Archie crossed the path he obviously caught a whiff of bird and started roading up the path.  I called him off the scent and sent him out again.  He quartered well covering good ground, nice and flat, and sure enough when he crossed the path he signalled scent again.  I sent him off to the left and he went out well, turned on the whistle and on his way back across went bang on point.  The stop was dramatic; so dramatic that he dropped flat down, nose held high into the heather.  I walked over and as I got within a few metres flushed a nice fat male red grouse from in front of him.  It flew off rapidly letting out its characteristic cackle.  Archie didn’t move.  He didn’t even stand up, he just watched it away.  I made a real fuss of him and we carried on quartering for another 15 minutes before heading home.  A good session that worked.  Thanks for the advice Des.

I then took Grace to the river.  I let her through the gate into the woods and told her to get on.  She did, after a pheasant.  She didn’t drop to my whistle – in fact she didn’t even appear to hear me.  I ran after her, put her back on the lead and brought her home.  I am going back to basics with Grace, starting tomorrow.

Sexo: Hembra

Edad: 00/01/09

Raza: X Pointer

Salud:

Asociación a la que pertenece: La Xana (http://www.laxana.org/adopciones/visualiza/617.html)

Otra que no sirve para cazar…¡pobre! La dejaron atada a la puerta del albergue y muerta frío y de miedo. Es tan solo una cachorrona ala que le cuesta confiar, pero una vez que lo hace, es muy juguetona y alegre. Solo quiere la compañía del ser humano.

I set out late this morning with the intention of spending a few hours on the heather.  The weather has been appalling with what seems like a week of solid rain, and today was no exception.  I set off, waterproofed to the hilt, and at the edge of the moorland cast Archie off, keeping Grace on her slip lead.  Archie ran ok, but we were up against a fence on one side and as the heather was very deep  he couldn’t really get into his stride.  The second photo though shows a peculiar problem that I have just discovered and shall have to work out how to overcome.  In an effort to ensure Archie didn’t take too big a bite at the end of his beat I would recall him towards me then recast him out across me again, but this time from a much closer position.  This has worked out fine until today when I had Grace on a lead at my side.  As Archie gets close, he sees Grace standing still, and backs her.  The first time this happened I thought he had a scent so moved forwards to encourage him to flush the bird.  It was then obvious that Archie was watching Grace, not pointing a bird.

I cast Archie off again and he did, very soon, pick up scent and roaded forwards until he reached the fence.  Because there was nowhere left to go I had to whistle him back which wasn’t ideal.  I moved forwards and cast both dogs off giving them very little instruction.  Grace worked the strong wind really well, keeping her beat nice and flat.  Neither dogs found a bird, so I picked them up and moved to another section of moorland.

I cast Archie off to the right and immediately to the right of me two jack snipe lifted.  I dropped Archie who only went into the ‘hupped position’ – note to self – this needs more work.  I have never come across jack snipe until this November but now seem to have seen a few.  Archie watched them flit away before I recast him.  We practised quartering and he did ok really although I really must bring him closer to me as he crosses (the white specks in the photos with the arrows are Archie). 

The wind was very strong and occasionally he would be pulled forwards.  At one point he really seemed to signal birds, but didn’t seem confident, so I dropped him and cast Grace off to see if she would pick up a scent.  She stopped in exactly the same spot and when I tried to send her out to the right looked back at me as if to ask why I was being so stupid.  I picked her up and decided to let Archie road in and find the bird as I really wanted him to get a bird under his nose for himself.  I cast him off and he ran out, turned then on his way past me, hesitated then started to road forwards.  He went a long way forwards then ahead of him rose a load of jack snipe (probably including the two we had flushed earlier).  I counted six but there could have been more.  I cast both dogs off to work out the area on the moorland edge and Grace flushed a snipe.  I dropped both dogs. 

I then decided to walk back up the hill over the ground we had just covered and work back down the hill into the wind again but a little further along.  That was the theory anyway.  In reality I veered off to the right and put up yet another jack snipe.  Neither dog was close enough to notice at the time which was a missed opportunity.  When we had moved far enough up the hill I turned and cast Archie off again, intent on improving his beat.  He did ok, and I followed him with Grace on her lead.  One thing I did notice though was if I stopped and Grace was standing leaning forwards against the tension on her lead Archie would stop and back her.  I really must ensure he works comfortably on his own and doesn’t start to rely on Grace to find the birds.  I don’t think this will be an issue but I need to ensure I do all I can to make sure I don’t inadvertently encourage this.

To think that I once wondered how I would ever train a pointer to back.

Archie really needs some birds of his own under his nose.  His backing is second to none but I can’t help but think he would benefit from some more finds of his own.  We went out this afternoon into the forest and Grace and Archie pointed very quickly, within seconds of getting out of the land rover.  Archie immediately backed Grace but it was obvious that both dogs had scent, with Archie ‘champing’ the air and following the scent in the air as it came to him, rather than just focussing on Grace on point.  As Grace roaded forwards, so Archie followed suit, keeping the same distance from Grace.  The scent obviously became very strong as Archie ‘champed’ the air more and more dramatically with every step.  He also sunk lower to the ground as he pulled forwards until he was actually on his belly.  I moved forward and four cock pheasants lifted from the conifers to the right from about 40 yards away.  The wind was very strong and the scent must have hit them both flat on.  I blasted the whistle and Archie maintained his belly down position, Grace ran a few yards before sitting (which isn’t really acceptable I know).

To break up the journey to Essex on Saturday we stopped off in Hampshire for the weekend at my brother’s.  He, as you may have read, has a lab – Charlie, and whilst Charlie has loads of energy, exercising him with two pointers does not help him learn to stay close.  With this in mind we exercised the dogs in two sessions each day.  We took Archie and Grace to a large public open space on the outskirts of Basingstoke and let them have a blast.  Now this is a very large open space, frequented by dog walkers and joggers so I knew that the distractions would be great.  Both dogs had a sprint about and whenever Archie looked to be heading towards another dog or jogger I dropped him on the whistle before recalling him.  He dropped every time and came back with a great eagerness.  I am really pleased with this.  At one point I just told them both to get on and Archie ran down hill to the boundary of the park.  My guess is that this was at least 500 yards away (the photo only shows him half way out).  I pipped the whistle when he got to the boundary and he turned and came charging back straight away.

‘Pointer running off’ is a common search term that people look for before finding this website and it did prompt a conversation with my brother at the time.  Archie returned to the whistle instantly, despite being so far away that I could barely see him.  If I didn’t have the confidence that he would have returned, effectively he would have ‘run off’.  Because I was confident that he would return to the whistle, and actively encourage him to cover this sort of ground, he was doing what I wanted him to do, and indeed what his genes determine that he will do.  The importance of a solid recall is therefore paramount.  Not only for the sake of safety, but also to allow the dog to do what it is programmed to do in a safe manner.  The difference between a pointer doing what it should and “running off” therefore seems to be determined by a combination of handler confidence and obedience to the whistle, not as it might appear the actual “running off” which to me is quite natural and to an extent completely predictable.  If I had a dog that didn’t “run off” I would be very disappointed, likewise I would feel very disappointed with myself if he didn’t immediately turn to the whistle.

Já ouvi pessoas reclamando pelo fato de que o java não possui ponteiro. Vejo nessa reclamação dois problemas:

1. Java possui sim ponteiro, dado que os objetos são passados por referência. O que o java não tem é aritmética de ponteiros e ponteiros para funções;
2. Será que realmente é bom utilizar ponteiro? Me parece que o caso em que realmente é justificável a utilização de ponteiros é na manipulação de grandes volumes de dados em memória, por questões de performance. Fora isso, nos 99% dos casos restantes a utilização de ponteiros normalmente indica uma deficiência de modelagem e é um fator de grande risco, caso o programador não tome os cuidados necessários.

Porém, como mesmo assim alguns não ficam satisfeitos com estas duas afirmações, escrevi este post. Nós já utilizamos ponteiros em java naturalmente, dado que a passagem de parâmetros é por referência. Para ter a funcionalidade de um ponteiro em java (sem aritmética), basta termos uma classe como essa:

package ponteiro;

public class PonteiroSimples<T> {

	T obj;

	public PonteiroSimples(T obj) {
		super();
		this.obj = obj;
	}

	public T getObj() {
		return obj;
	}

	public void setObj(T obj) {
		this.obj = obj;
	}

}

Um trecho de código em C/C++ que ficaria assim:

Teste *p = &a;
Teste b = *p;

ficaria:

Ponteiro<Teste> p = new Ponteiro(a);
Teste b = p.getObj;

Porém, com o PonteiroSimples não é possível utilizar aritmética de ponteiros. Para utilizar aritmética, implementei duas abordagens.
A primeira simula aritmética de ponteiros utilizando um Map para mapear endereços fictícios de memória. A segunda mostra que é possível utilizar ponteiros e aritmética de ponteiros na VM da Sun, através do sun.misc.Unsafe que utilizei no post “Hackeando o java”. Nas duas abordagens não me preocupei com ponteiros para função e alocação de memória, embora acredite que também seja possível implementar.

Antes de apresentá-las, gostaria de reforçar que estas abordagens são somente provas de conceito! Não utilizem elas!

As duas abordagens possuem duas classes e uma interface em comum:

1. PonteiroTest

package ponteiro;

import static org.junit.Assert.*;
import static ponteiro.Ponteiro.*;

import org.junit.*;

public class PonteiroTest {

	public static class Teste {
		String string;

		public Teste(String string) {
			super();
			this.string = string;
		}
	}

	@Test
	public void testPonteiroNormal() throws Exception {
		Teste teste = new Teste("1");

		// Teste *ponteiro = &teste;
		Ponteiro<Teste> ponteiro = getPonteiro(teste);

		// Teste objeto = *ponteiro;
		Teste objeto = ponteiro.getObjeto();
		assertEquals(teste, objeto);
	}

	@Test
	public void testPonteiroDePonteiro() throws Exception {
		Teste teste = new Teste("2");

		// Teste *aux = &teste;
		// Teste **ponteiro = &aux;
		Ponteiro<Ponteiro<Teste>> ponteiro = getPonteiro(getPonteiro(teste));

		// Teste objeto = **ponteiro;
		Teste objeto = ponteiro.getObjeto().getObjeto();
		assertEquals(teste, objeto);
	}

	@Test
	public void testPonteiroAritmetica() throws Exception {
		Teste[] testeArray = new Teste[3];
		testeArray[0] = new Teste("0");
		testeArray[1] = new Teste("1");
		testeArray[2] = new Teste("2");
		Teste[] testeArray2 = new Teste[3];

		// Teste *ponteiro = testeArray;
		Ponteiro<Teste> ponteiro = getPonteiro(testeArray);
		// testeArray2[0] = *ponteiro;
		testeArray2[0] = ponteiro.getObjeto();

		// ponteiro++;
		ponteiro.adiciona(1);
		// testeArray2[1] = *ponteiro;
		testeArray2[1] = ponteiro.getObjeto();

		// ponteiro++;
		ponteiro.adiciona(1);
		// testeArray2[2] = *ponteiro;
		testeArray2[2] = ponteiro.getObjeto();

		assertArrayEquals(testeArray, testeArray2);
	}

}

2. Ponteiro

package ponteiro;

public class Ponteiro<T> {

	static {
		String tipo = System.getProperty("tipoMemoria", "fake");
		if(MemoriaReal.TIPO.equalsIgnoreCase(tipo)){
			memoria = new MemoriaReal();
		}
		else if(MemoriaFake.TIPO.equalsIgnoreCase(tipo)) {
			memoria = new MemoriaFake();
		}
		else {
			throw new IllegalStateException("Parametro tipoMemoria inválido!");
		}
	}

	private static Memoria memoria;

	private long endereco;

	public static <T> Ponteiro<T> getPonteiro(T obj) {
		return new Ponteiro<T>(memoria.getEndereco(obj));
	}

	public static <T> Ponteiro<T> getPonteiro(T[] obj) {
		return new Ponteiro<T>(memoria.getEndereco(obj));
	}

	public static <T> long getEndereco(T obj) {
		return memoria.getEndereco(obj);
	}

	public static <T> T getObjeto(long endereco) {
		return new Ponteiro<T>(endereco).getObjeto();
	}

	private Ponteiro(long endereco) {
		super();
		this.endereco = endereco;
	}

	@SuppressWarnings("unchecked")
	public T getObjeto() {
		return (T) memoria.getObject(endereco);
	}

	public long adiciona(long posicoes) {
		return endereco = memoria.adiciona(endereco, posicoes);
	}
}

3. Memoria

package ponteiro;

public interface Memoria {

	public long getEndereco(Object obj);
	public Object getObject(long endereco);
	public long adiciona(long endereco, long posicoes);

}

O que varia é a escolha de implementação de Memoria, dependendo da abordagem.

• Ponteiros em java “puro”

package ponteiro;

import java.util.*;

public class MemoriaFake implements Memoria {

	public static final String TIPO = "fake";
	static Map<Long, Object> map = new WeakHashMap<Long, Object>();
	private static long livre = 0;

	@Override
	public long getEndereco(Object obj) {
		long retorno = 0;
		if (obj != null) {
			// O Java não tem map birecional!?
			Set<Long> keySet = map.keySet();
			for (Long endereco : keySet) {
				if (obj.equals(map.get(endereco))) {
					retorno = endereco;
				}
			}
			if (retorno == 0) {
				if (obj.getClass().isArray()) {
					Object[] array = (Object[]) obj;
					long inicio = livre;
					for (Object object : array) {
						map.put(livre++, object);
					}
					retorno = inicio;
				} else {
					map.put(livre, obj);
					retorno = livre++;
				}
			}
		}
		return retorno;
	}

	@Override
	public Object getObject(long endereco) {
		return map.get(endereco);
	}

	@Override
	public long adiciona(long endereco, long posicoes) {
		return endereco + posicoes;
	}

}

• Ponteiros “verdadeiros” na VM da Sun

package ponteiro;

import java.lang.reflect.*;

import net.sourceforge.sizeof.*;
import sun.misc.*;

public class MemoriaReal implements Memoria {

	public static final String TIPO = "real";
	private static Unsafe unsafe = getUnsafe();

	private static Unsafe getUnsafe() {
		Unsafe unsafe = null;
		try {
			Field field = Unsafe.class.getDeclaredField("theUnsafe");
			field.setAccessible(true);
			unsafe = (Unsafe) field.get(Unsafe.class);
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
		return unsafe;
	}

	private static class Auxiliar {
		Object obj;
	}

	@SuppressWarnings("deprecation")
	@Override
	public long getEndereco(Object obj) {
		Auxiliar aux = getAux(obj);
		long fieldOffset = getFieldOffset(aux, "obj");
		long endereco = unsafe.getLong(aux, fieldOffset);
		if (obj.getClass().isArray()) {
			int arrayBaseOffset = unsafe.arrayBaseOffset(obj.getClass());
			endereco = unsafe.getInt(obj, arrayBaseOffset);
		}
		return endereco;
	}

	private Auxiliar getAux(Object obj) {
		Auxiliar aux = new Auxiliar();
		aux.obj = obj;
		return aux;
	}

	@Override
	public Object getObject(long endereco) {
		Auxiliar aux = getAux(null);
		long fieldOffset = getFieldOffset(aux, "obj");
		unsafe.putLong(aux, fieldOffset, endereco);
		return aux.obj;
	}

	@SuppressWarnings("deprecation")
	private static long getFieldOffset(Object obj, String field) {
		try {
			return unsafe.fieldOffset(obj.getClass().getDeclaredField(field));
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	@Override
	public long adiciona(long endereco, long posicoes) {
		Object obj = getObject(endereco);
		long size = SizeOf.sizeOf(obj);
		return endereco + size;
	}

}

Para facilitar, disponibilizei o projeto do eclipse no google code:

svn checkout http://ponteiros.googlecode.com/svn/trunk/ ponteiros-read-only

Rode o teste jUnit adicionando os parâmetros de VM:

-javaagent:lib\SizeOf.jar -DtipoMemoria=fake

Ou

-javaagent:lib\SizeOf.jar -DtipoMemoria=real

Conclusão

Em 99% dos casos, é uma falácia dizer que é uma deficiência o java não possuir ponteiros. É possível ter as principais funcionalidades de ponteiros no java através de uma classe como o PonteiroSimples, porém creio que utilizar uma abordagem como essa na maioria dos casos indica uma má modelagem do sistema e devemos tomar cuidado para utilizá-la.

Após, demonstrei que é possível utilizar aritmética de ponteiros no java simulando a memória com um Map. É uma implementação bem simples que possui uma série de deficiências, porém prova que é possível ter a funcionalidade de aritmética de ponteiros utilizando código java “puro”.

Para finalizar, fiz uma “viagem” com o sun.misc.Unsafe que nos dá acesso direto à memória para poder realizar aritmética de ponteiros. Também vejo algumas deficiências nesta abordagem e novamente ressalto que ela foi colocada aqui apenas como prova de conceito. Jamais utilize ela em uma aplicação!

Sexo: Macho

Edad: 00/02/08

Raza: X Pointer

Salud:

Asociación a la que pertenece: La Xana (http://www.laxana.org/adopciones/visualiza/428.html)

Como todos los perros de caza y sus cruces, este es un animal ideal para familias con niños, pues son pacientes y tremendamente cariñosos, obediente y noble.

Sexo: Macho

Edad: 25/09/09

Raza: X Pointer

Salud:

Asociación a la que pertenece: La Xana (http://www.laxana.org/adopciones/visualiza/603.html)

Más pequeño que su hermana Vilma. Será un animal activo cuando sea mayor. Los de su raza son especialemnte cariñosos con niños. Ideal para una familia.

Sexo: Hembra

Edad: 25/09/09

Raza: X Pointer

Salud:

Asociación a la que pertenece: La Xana (http://www.laxana.org/adopciones/visualiza/604.html)

Cariñosa y espabilada. Cuando sea mayor será una perra activa y sociable.

Sexo: Macho

Edad: 2005

Raza: Pointer

Salud:

Asociación a la que pertenece: Amigos del perro

Se lleva bien con las personas, machos y hembras. Es activo.

Sexo: Hembra

Edad: 2003-2004

Raza: Pointer

Salud:

Asociación a la que pertenece: Amigos del perro (http://www.amigosdelperro.org/galeria/details.php?image_id=4766&mode=search)

Se lleva bien con machos y hembras, con humanos es un poco desconfiada al principio.

Sexo:  Hembra

Edad: 2004

Raza: X Pointer

Salud:

Asociación donde se encuentra:  Amigos del perro (http://www.amigosdelperro.org/galeria/details.php?image_id=4711&mode=search)

Es muy tímida con las personas que no conoce. Se lleva bien con machos y hembras, cuando ya coge confianza es muy muy cariñosa.

Zipper is a little bit of a mystery, which makes him all the more unique! He appears to be of the scruffy persuasion, and our best guess is crossed with pointer, possibly a German Wirehaired in dress whites…?  He’s overall white with a sprinkling of liver spots, a wiry rather than soft coat.  He is of medium size, apx 50 lbs, thin build and a year old, well mannered and leash trained.   Vol says he is very, very friendly and outgoing, a true ‘love bug’, who takes treats ever so politely. He’s got an almost regal, lofty air to him…a real head turner

Zipper’s neuter and rabies shot will be sponsored …so he will be good to go. Before that can happen, he needs somewhere to go!

He is in run 91, ID# 3355

http://www.petfinder.com/petnote/displaypet.cgi?petid=14973520

If you are able to help – please contact:

Cobb County Animal Control
MARIETTA, GA

Cindy Ganues
Phone: 770-590-5621
Fax: 770-590-5620
Cynthia.Ganues@cobbcounty.org
She will return your call \ email even if she in not working that day.

OR

Shannon Witt
Phone: 770-590-5624
Fax: 770-590-5620
Shannon.Witt@cobbcounty.org

If you could look into the future and know what your next training session would throw at you it may seem less risky to change plans and opt for a walk in the nearest park.  Today was one of those days.

I took both dogs into the forest this afternoon and started off in a relaxed mood, having decided to let the dogs have a good run without my boring voice interjecting.  I let them out of the back of the car without leads and told them just to get on.  Grace ran a few yards before stopping to sniff about and Archie ran ahead for about 50 yards before acknowledging something and drawing forwards in a semi-crouched, half stalk, type of way.  He then stalked his way up the path for a little way before I thought that he was just having me on.  Grace was strolling along beside him and nothing seemed to be coming to anything.  In an effort to break him out of this non productive stalk I dropped him using the whistle.  He dropped straight away but Grace just sat in the hupped position rather than dropping.  In an effort to drop her I ran at her waving my hat, but instead of this having the desired effect I flushed a snipe to the side of the path – the snipe that Archie must have got scent of earlier.  Both dogs watched the bird away as you can see from the photo and I let them get on, realising that I know nothing and I should trust Archie a little more.  I then practised the ‘get on’ and the recall with no problems.

I then decided to head onto the heather for half an hour,  I set both dogs up then told them to get on, not really worrying where they went.  Both dogs had a blast and agreed on the wind direction which was good to see.  I let them get a good way out before practising the drop to the whistle, which Archie did well and Grace nearly got right – she would hup, then move towards me when I walked away.  I ended up having to walk a long way out to her to put her back in position.  Whilst I was doing this Archie just stayed put in the heather.  I then cast both dogs off again and within seconds Archie signalled a bird.  He roaded in for a long while before reaching the moorland edge and the forest fence, at which point I called him back and recast him.  Grace continued to hunt behind me, not once even showing the slightest inclination to back.

I then cast Archie off and the 7th and 8th photos show what happened.  I let him get out as far as he wanted, he then turned and ran forwards taking a bigger bite than I would have liked.  I decided to photograph this for the record before turning him (I had my whistle in my mouth).  As he pulled forwards he flushed a pheasant (I don’t think he pointed at all but it was too far away to tell with any certainty).  As I saw the bird lift I blasted on my whistle and he dropped to the ground.  The 8th photo is a zoomed in version of the 7th and you can see Archie dropped and the pheasant heading off.  His drop was superb, but he should have pointed rather than bumped the bird.  He needs more exposure to game really.  I was pleased though.  The command to drop was given over a very long distance and he stopped and dropped instantly.

I cast both dogs off again and within minutes Grace was on point and Archie was backing.  I moved in and encouraged Grace forwards, which she did, to put up a hen pheasant.  I blew the whistle and Archie dropped instantly, whilst Grace ran into the trees after the bird.  Within seconds she had appeared and sat, waiting – just far enough away to avoid any reminders of my displeasure at her chase.

An odd session that was a bit of a curate’s egg.

Sexo: Hembra

Edad: Abril del 2007

Raza: Pointer

Salud:

Asociación a la que pertenece: Amigos del perro (http://www.amigosdelperro.org/galeria/details.php?image_id=5031&mode=search)

No caza. Muy activa, sociable y cariñosa. Le encanta ir de paseo pero aún tira de la correa. Le encantan los mimos!

Sexo: Hembra

Edad: 2002

Raza: X Caza

Salud:

Asociación a la que pertenece: Amigos del perro (http://www.amigosdelperro.org/galeria/details.php?image_id=2917&mode=search)

Probablemente cruce de setter. De lo más cariñosa y sociable. Es más grande que un perro de caza y bastante gordita, pues le gusta comer. Duerme la siesta. Estuvo un año abandonada en el monte.