Java/DataStructures/DynamicArray/DynamicArray.java at master · leewalter/Java · GitHub

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package DataStructures.DynamicArray;

import java.util.Arrays;

import java.util.ConcurrentModificationException;

import java.util.Iterator;

import java.util.NoSuchElementException;

import java.util.Objects;

import java.util.function.Consumer;

import java.util.stream.Stream;

import java.util.stream.StreamSupport;

public class DynamicArray<E> implements Iterable<E> {

private int capacity = 10;

private int size = 0;

private Object[] elements;

public DynamicArray(final int capacity) {

this.capacity = capacity;

this.elements = new Object[this.capacity];

}

public DynamicArray() {

this.elements = new Object[this.capacity];

}

public int newCapacity() {

this.capacity <<= 1;

return this.capacity;

}

public void add(final E element) {

if (this.size == this.elements.length)

this.elements = Arrays.copyOf(this.elements, newCapacity());

this.elements[this.size] = element;

size++;

}

public void put(final int index, E element) {

Objects.checkIndex(index, this.size);

this.elements[index] = element;

}

public E get(final int index) {

return getElement(index);

}

public E remove(final int index) {

final E oldElement = getElement(index);

fastRemove(this.elements, index);

return oldElement;

}

public int size() {

return this.size;

}

public boolean isEmpty() {

return this.size == 0;

}

public Stream<E> stream() {

return StreamSupport.stream(spliterator(), false);

}

private void fastRemove(final Object[] elements, final int index) {

final int newSize = this.size - 1;

if (newSize > index)

System.arraycopy(elements, index + 1, elements, index, newSize - index);

elements[this.size = newSize] = null;

}

private E getElement(final int index) {

Objects.checkIndex(index, this.size);

return (E) this.elements[index];

}

@Override

public String toString() {

return Arrays.toString(Arrays.stream(this.elements).filter(Objects::nonNull).toArray());

}

@Override

public Iterator iterator() {

return new DynamicArrayIterator();

}

private class DynamicArrayIterator implements Iterator<E> {

private int cursor;

@Override

public boolean hasNext() {

return this.cursor != size;

}

@Override

public E next() {

if (this.cursor > DynamicArray.this.size) throw new NoSuchElementException();

if (this.cursor > DynamicArray.this.elements.length) throw new ConcurrentModificationException();

final E element = DynamicArray.this.getElement(this.cursor);

this.cursor++;

return element;

}

@Override

public void remove() {

if (this.cursor < 0) throw new IllegalStateException();

DynamicArray.this.remove(this.cursor);

this.cursor--;

}

@Override

public void forEachRemaining(Consumer<? super E> action) {

Objects.requireNonNull(action);

for (int i = 0; i < DynamicArray.this.size; i++) {

action.accept(DynamicArray.this.getElement(i));

}

public static void main(String[] args) {

DynamicArray<String> names = new DynamicArray<>();

names.add("Peubes");

names.add("Marley");

for (String name : names) {

System.out.println(name);

}

names.stream().forEach(System.out::println);

System.out.println(names);

System.out.println(names.size());

names.remove(0);

for (String name : names) {

System.out.println(name);

}

Java/DataStructures/DynamicArray/DynamicArray.java at master · leewalter/Java · GitHub

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