Taking an element out of an array
I'm trying to take an animal element of an array for filtering but I'm having some problems. I need to take the element i need out of the array. Then I need to find out whether the animal is the type I need. Finally I need to add the animal object to the array. I have to seperate arrays of displayed animals and all the animals but I'm just having trouble figuring out how to do the above. Any advice is greatly appreciated. Here's what I have so far:
Code :
public void filterDogs()
{
Iterator i = animals.iterator();
while(i.hasNext())
{
Animal a = (Animal)i.next();
if(a instanceof Dog)
Dog += displayedAnimals.add(a);
}
}
And the entire code:
Code :
import javax.swing.*;
import java.util.ArrayList;
import java.util.*;
import java.util.Collections;
import javax.swing.Timer;
public class AnimalListDisplay extends JList
{
ArrayList<Animal> animals;
ArrayList<Animal> displayedAnimals;
boolean specialNeedsOnly = false;
boolean birdsOn = false;
boolean dogsOn = false;
boolean catsOn = false;
public AnimalListDisplay(ArrayList<Animal> allAnimals)
{
animals = allAnimals;
displayedAnimals = animals;
}
public void addAnimal(Animal animal)
{
animals.add(animal);
setListData(animals.toArray());
}
public void sortAge()
{
AgeCompare a1 = new AgeCompare();
Collections.sort(displayedAnimals, a1);
setListData(displayedAnimals.toArray());
}
public void sortSize()
{
Collections.sort(displayedAnimals);
setListData(displayedAnimals.toArray());
}
public void filterSpecialNeeds()
{
if(specialNeedsOnly == false)
{
displayedAnimals = new ArrayList<Animal>();
Iterator i = animals.iterator();
while(i.hasNext())
{
Animal a = (Animal)i.next();
if(a.getNeeds())
displayedAnimals.add(a);
}
setListData(displayedAnimals.toArray());
specialNeedsOnly = true;
}
else if(specialNeedsOnly == true)
{
setListData(animals.toArray());
specialNeedsOnly = false;
}
}
// public void addAnimal(Animal pet){
// displayedAnimals.add(pet);
// animals.add(pet);
public void filterDogs()
{
Iterator i = animals.iterator();
while(i.hasNext())
{
Animal a = (Animal)i.next();
if(a instanceof Dog)
displayedAnimals.add(a);
}
}
public void filterCats()
{
if(catsOn == false)
{
displayedAnimals = new ArrayList<Animal>();
Iterator i = animals.iterator();
while(i.hasNext())
{
Animal a = (Animal)i.next();
if(a.getNeeds())
displayedAnimals.add(a);
}
setListData(displayedAnimals.toArray());
catsOn = true;
}
else if(catsOn == true)
{
setListData(animals.toArray());
catsOn = false;
}
}
public void filterBirds()
{
if(birdsOn == false)
{
displayedAnimals = new ArrayList<Animal>();
Iterator i = animals.iterator();
while(i.hasNext())
{
Animal a = (Animal)i.next();
if(a.getNeeds())
displayedAnimals.add(a);
}
setListData(displayedAnimals.toArray());
birdsOn = true;
}
else if(birdsOn == true)
{
setListData(animals.toArray());
birdsOn = false;
}
}
}
Re: Taking an element out of an array
Your thinking way to difficult dude.
Code :
public abstract class Animals
{
public static final Integer CATS = 0;
public static final Integer DOGS = 1;
public static final Integer BIRDS = 2;
protected Hashtable<Animal> animals = new Hashtable<Animal>(); //protected!!!
public abstract Hashtable<Animal> collect(int specieType);
public abstract void add(Animal a);
public abstract Animal get(int id);
public abstract void edit(Animal a);
public abstract boolean remove(Animal a);
}
public class AnimalCollection extends Animals
{
private Hashtable<Animal> collection = new Hashtable<Animal>();
public Hashtable<Animal> collect(int specieType)
{
String specie;
switch(specieType)
{
case 0:
specie = "Cat";
break;
case 1:
specie = "Dog";
break;
case 2:
specie = "Bird";
break;
default:
throw new Exception("Unknown type.");
}
Hashtable<Animal> col = new hashtable<Animal>();
for(Animal a : super.animals)
{
if(a instanceof specie)
{
col.put(a.hashCode(), a);
}
}
this.collection = col; //if you want to have the same collection some time later, you load this and dont call the method again(performance)
return col;
}
@override
public void add(Animal a) {}
@override
public Animal get(int id) {}
@override
public void edit(Animal a) {}
@override
public boolean remove(Animal a) {}
}
Call:
AnimalCollection aC = new AnimalCollection();
Hashtable dogsCollection = aC.collect(Animals.DOGS);
I made this with notepad++ so there may be some syntax errors.
Re: Taking an element out of an array
Re: Taking an element out of an array
Quote:
Originally Posted by
Bryan
Code :
public abstract class Animals
{
public static final Integer CATS = 0;
public static final Integer DOGS = 1;
public static final Integer BIRDS = 2;
protected Hashtable<Animal> animals = new Hashtable<Animal>(); //protected!!!
public abstract Hashtable<Animal> collect(int specieType);
public abstract void add(Animal a);
public abstract Animal get(int id);
public abstract void edit(Animal a);
public abstract boolean remove(Animal a);
}
public class AnimalCollection extends Animals
{
private Hashtable<Animal> collection = new Hashtable<Animal>();
public Hashtable<Animal> collect(int specieType)
{
String specie;
switch(specieType)
{
case 0:
specie = "Cat";
break;
case 1:
specie = "Dog";
break;
case 2:
specie = "Bird";
break;
default:
throw new Exception("Unknown type.");
}
Hashtable<Animal> col = new hashtable<Animal>();
for(Animal a : super.animals)
{
if(a instanceof specie)
{
col.put(a.hashCode(), a);
}
}
this.collection = col; //if you want to have the same collection some time later, you load this and dont call the method again(performance)
return col;
}
@override
public void add(Animal a) {}
@override
public Animal get(int id) {}
@override
public void edit(Animal a) {}
@override
public boolean remove(Animal a) {}
}
Call:
AnimalCollection aC = new AnimalCollection();
Hashtable dogsCollection = aC.collect(Animals.DOGS);
I made this with notepad++ so there may be some syntax errors.
Hmm, that needs a bit more work...
Don't forget that a Hashtable is a keyed collection, so should be declared with two generic type arguments - but a Hashtable won't work here if you want more than one instance of each species in the collection - Hashtable keys are unique.
You could profitably replace the Integer 'specieType' with an enum.
It would simplify things if an Animal knew its specieType - which it should.
Should AnimalCollection really extend Animals, or does this complicate things?
There seems little point in having a Hashtable of a single animal species, ArrayList would be more appropriate (especially if an Animal knows its Species)?
If all that's needed is to extract a particular species from a mixed collection, wouldn't something like this be simpler:
Code :
import java.util.ArrayList;
import java.util.List;
class AnimalFilter
{
public static void main(String[] args) {
List<Animal> animals = new ArrayList<Animal>();
animals.add(new Dog(..));
animals.add(new Cat(..));
animals.add(new Bird(..));
animals.add(new Dog(..));
animals.add(new Bird(..));
AnimalFilter filter = new AnimalFilter();
List<Animal> dogsCollection = filter.collect(animals, Animal.Species.DOGS);
... // do something with Dogs
}
public List<Animal> collect(List<Animal> animals, Animal.Species species)
{
List<Animal> selectedAnimals = new ArrayList<Animal>();
for(Animal animal : animals)
{
if(animal.isSpecies(species)) {
selectedAnimals.add(animal);
}
}
return selectedAnimals;
}
}
abstract class Animal {
public enum Species { CATS, DOGS, BIRDS }
protected Species species;
public Species getSpecies() {
return species;
}
public boolean isSpecies(Species s) {
return species == s;
}
}
class Dog extends Animal { ... }
class Cat extends Animal { ... }
class Bird extends Animal { ... }
If an explicit Species type id isn't needed, you could even get rid of the Species enum and just use the Animal class type:
Code :
class AnimalFilter
{
public static void main(String[] args) {
List<Animal> animals = new ArrayList<Animal>();
animals.add(new Dog(..));
animals.add(new Cat(..));
animals.add(new Bird(..));
animals.add(new Dog(..));
animals.add(new Bird(..));
AnimalFilter filter = new AnimalFilter();
List<Animal> dogsCollection = filter.collect(animals, Dog.class);
... // do something with Dogs
}
public List<Animal> collect(List<Animal> animals, Class speciesClass)
{
List<Animal> selectedAnimals = new ArrayList<Animal>();
for(Animal animal : animals)
{
if(animal.getClass().equals(speciesClass)) {
selectedAnimals.add(animal);
}
}
return selectedAnimals;
}
}
abstract class Animal { ... }
class Dog extends Animal { ... }
class Cat extends Animal { ... }
class Bird extends Animal { ... }
YMMV.
