всем привет. подскажите по итератору пожалуйста. нужно логику из метода hasNext перенести в next. подскажите как реализовать.
| Код |
public class HashTable<E> implements Collection<E> {
private static final int DEFAULT_CAPACITY = 20;
private ArrayList<E>[] hashTable;
public HashTable() {
this(DEFAULT_CAPACITY);
}
public HashTable(int sizeOfTable) {
if (sizeOfTable <= 0) {
throw new IllegalArgumentException("Некорректный размер таблицы");
}
this.hashTable = new ArrayList[sizeOfTable];
}
public int getLength() {
return hashTable.length;
}
public int positionInMainArray(Object o) {
return Math.abs(o.hashCode()) % hashTable.length;
}
@Override
public int size() {
int numberOfElements = 0;
for (ArrayList<E> aHashTable : hashTable) {
if (aHashTable != null) {
numberOfElements += aHashTable.size();
}
}
return numberOfElements;
}
@Override
public boolean isEmpty() {
return this.size() == 0;
}
@Override
public boolean add(E element) {
if (element == null) {
throw new NullPointerException();
}
int index = positionInMainArray(element);
if (hashTable[index] == null) {
hashTable[index] = new ArrayList<>();
hashTable[index].add(element);
return true;
} else {
if (hashTable[index].contains(element)) {
return false;
} else {
hashTable[index].add(element);
return true;
}
}
}
@Override
public boolean remove(Object obj) {
if (obj == null) {
return false;
} else {
int index = positionInMainArray(obj);
return hashTable[index] != null && hashTable[index].remove(obj);
}
}
@Override
public boolean contains(Object obj) {
if (obj == null) {
throw new NullPointerException();
}
int index = positionInMainArray(obj);
return hashTable[index] != null && hashTable[index].contains(obj);
}
@Override
public void clear() {
for (ArrayList<E> aHashTable : hashTable) {
if (aHashTable != null) {
aHashTable.clear();
}
}
}
@Override
public Object[] toArray() {
List<E> newList = new ArrayList<>();
for (ArrayList<E> aHashTable : hashTable) {
if (aHashTable != null) {
newList.addAll(aHashTable);
}
}
return newList.toArray();
}
@Override
public <T> T[] toArray(T[] a) {
if (a.length < this.size()) {
return (T[]) Arrays.copyOf(this.toArray(), this.size(), a.getClass());
}
int k = 0;
for (ArrayList<E> currentBucket : hashTable) {
if (currentBucket != null) {
for (E currentElement : currentBucket) {
a[k] = (T) currentElement;
k++;
}
}
}
if (a.length > this.size()) {
a[this.size()] = null;
}
return a;
}
@Override
public boolean containsAll(Collection<?> c) {
List<E> newList = new ArrayList<>();
for (ArrayList<E> aHashTable : hashTable) {
if (aHashTable != null) {
newList.addAll(aHashTable);
}
}
return newList.containsAll(c);
}
@Override
public boolean addAll(Collection<? extends E> c) {
int count = 0;
for (E currentElement : c) {
if (this.add(currentElement)) {
count++;
}
}
return count > 0;
}
@Override
public boolean removeAll(Collection<?> c) {
int count = 0;
for (Object currentElement : c) {
if (this.remove(currentElement)) {
count++;
}
}
return count > 0;
}
@Override
public boolean retainAll(Collection<?> c) {
int count = 0;
for (Object currentElement : c) {
int index = positionInMainArray(currentElement);
if (hashTable[index].retainAll(c)) {
count++;
}
}
return count > 0;
}
@Override
public Iterator<E> iterator() {
return new MyHashTablesIterator();
}
private class MyHashTablesIterator implements Iterator<E> {
private int bucketPosition;
private Iterator<E> listIterator;
@Override
public boolean hasNext() {
boolean result = false;
if (bucketPosition >= hashTable.length) {
return false;
}
while (bucketPosition < hashTable.length) {
if (hashTable[bucketPosition] == null) {
bucketPosition++;
} else {
if (listIterator == null) {
listIterator = hashTable[bucketPosition].iterator();
}
result = listIterator.hasNext();
if (result) {
break;
} else {
listIterator = null;
bucketPosition++;
}
}
}
return result;
}
@Override
public E next() {
if (!hasNext()) {
throw new NoSuchElementException("the end");
}
return listIterator.next();
}
}
}
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