11章-练习30

//参考 AbstractCollection 实现类

import com.example.demo.typeinfo.pets.Pet;
import com.example.demo.typeinfo.pets.Pets;

import java.util.Collection;
import java.util.Iterator;

/**
 * 练习30:修改CollectionSequence.java,使其不要继承AbstractCollection，而实现Collection
 */
public class CollectionSequenceV2 implements Collection<Pet> {

    private Pet[] pets = Pets.createArray(10);

    @Override
    public int size() {
        return pets.length;
    }

    @Override
    public boolean isEmpty() {
        return pets == null || pets.length == 0;
    }

    @Override
    public boolean contains(Object o) {
        Iterator<Pet> it = iterator();
        if (o==null) {
            while (it.hasNext())
                if (it.next()==null)
                    return true;
        } else {
            while (it.hasNext())
                if (o.equals(it.next()))
                    return true;
        }
        return false;
    }

    @Override
    public Iterator<Pet> iterator() {
        return null;
    }

    @Override
    public Object[] toArray() {
        return new Object[0];
    }

    @Override
    public <T> T[] toArray(T[] a) {
        return null;
    }

    @Override
    public boolean add(Pet pet) {
        return false;
    }

    @Override
    public boolean remove(Object o) {
        return false;
    }

    @Override
    public boolean containsAll(Collection<?> c) {
        return false;
    }

    @Override
    public boolean addAll(Collection<? extends Pet> c) {
        return false;
    }

    @Override
    public boolean removeAll(Collection<?> c) {
        return false;
    }

    @Override
    public boolean retainAll(Collection<?> c) {
        return false;
    }

    @Override
    public void clear() {

    }
}