com.sun.grizzly.utils.LightArrayList Maven / Gradle / Ivy
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package com.sun.grizzly.utils;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
/**
* Lighter version of {@link ArrayList}, which internaly uses array offset, to
* avoid redundant array shifting when executing add, remove methods.
*
* @author Alexey Stashok
*/
public class LightArrayList implements List {
private Object[] array;
private int size;
private int offset;
public LightArrayList() {
this(16);
}
public LightArrayList(int initialCapacity) {
array = new Object[initialCapacity];
}
public LightArrayList(List parentList, int fromIndex, int toIndex) {
this(Math.max(16, toIndex - fromIndex));
size = toIndex - fromIndex;
for(int i=0; i 0) {
ensureCapacity(size + diff);
}
this.size = size;
}
public boolean isEmpty() {
return size == 0;
}
public boolean contains(Object o) {
return indexOf(o) >= 0;
}
public Object[] toArray() {
Object[] result = new Object[size];
System.arraycopy(array, offset, result, 0, size);
return result;
}
public T[] toArray(T[] a) {
if (a.length < size) {
a = (T[]) java.lang.reflect.Array.newInstance(
a.getClass().getComponentType(), size);
}
System.arraycopy(array, offset, a, 0, size);
if (a.length > size) {
a[size] = null;
}
return a;
}
public boolean add(E e) {
ensureCapacity(size + 1);
array[offset + size++] = e;
return true;
}
public void add(int index, E element) {
throw new UnsupportedOperationException("Not supported yet.");
}
public boolean addAll(Collection c) {
Object[] a = c.toArray();
int numNew = a.length;
ensureCapacity(numNew + size); // Increments modCount
System.arraycopy(a, 0, array, offset + size, numNew);
size += numNew;
return numNew != 0;
}
public boolean addAll(int index, Collection c) {
Object[] a = c.toArray();
int numNew = a.length;
ensureCapacity(numNew + size); // Increments modCount
int numMoved = size - index;
if (numMoved > 0) {
System.arraycopy(array, index + offset, array, index + offset + numNew,
numMoved);
}
System.arraycopy(a, 0, array, index + offset, numNew);
size += numNew;
return numNew != 0;
}
public E remove(int index) {
E oldValue = (E) array[offset + index];
if (index == offset) {
offset++;
size--;
return oldValue;
}
int numMoved = size - index - 1;
if (numMoved > 0) {
System.arraycopy(array, offset + index + 1, array, offset + index,
numMoved);
}
size--;
return oldValue;
}
public boolean remove(Object o) {
if (o == null) {
for (int index = 0; index < size; index++) {
if (array[index] == null) {
remove(index);
return true;
}
}
} else {
for (int index = 0; index < size; index++) {
if (o.equals(array[index])) {
remove(index);
return true;
}
}
}
return false;
}
public boolean removeAll(Collection c) {
boolean modified = false;
Iterator e = iterator();
while (e.hasNext()) {
if (c.contains(e.next())) {
e.remove();
modified = true;
}
}
return modified;
}
public boolean containsAll(Collection c) {
Iterator e = c.iterator();
while (e.hasNext()) {
if (!contains(e.next())) {
return false;
}
}
return true;
}
public boolean retainAll(Collection c) {
boolean modified = false;
Iterator e = iterator();
while (e.hasNext()) {
if (!c.contains(e.next())) {
e.remove();
modified = true;
}
}
return modified;
}
public void clear() {
offset = 0;
size = 0;
}
public E get(int index) {
return (E) array[index + offset];
}
public E set(int index, E element) {
int i = index + offset;
E oldValue = (E) array[i];
array[i] = element;
return oldValue;
}
public int indexOf(Object o) {
if (o == null) {
for (int i = 0; i < size; i++) {
if (array[i + offset] == null) {
return i;
}
}
} else {
for (int i = 0; i < size; i++) {
if (o.equals(array[i + offset])) {
return i;
}
}
}
return -1;
}
public int lastIndexOf(Object o) {
if (o == null) {
for (int i = size - 1; i >= 0; i--) {
if (array[i + offset] == null) {
return i;
}
}
} else {
for (int i = size - 1; i >= 0; i--) {
if (o.equals(array[i + offset])) {
return i;
}
}
}
return -1;
}
public Iterator iterator() {
return new Iterator() {
private int index = -1;
public boolean hasNext() {
return (index + 1) < size;
}
public E next() {
return get(++index);
}
public void remove() {
LightArrayList.this.remove(index);
}
};
}
public ListIterator listIterator() {
return listIterator(-1);
}
public ListIterator listIterator(final int i) {
return new ListIterator() {
private int index = i;
public boolean hasNext() {
return index + 1 < size;
}
public E next() {
return get(++index);
}
public boolean hasPrevious() {
return index - 1 >= 0;
}
public E previous() {
return get(--index);
}
public int nextIndex() {
return index + 1;
}
public int previousIndex() {
return index - 1;
}
public void remove() {
LightArrayList.this.remove(index);
}
public void set(E e) {
LightArrayList.this.set(index, e);
}
public void add(E e) {
throw new UnsupportedOperationException("Not supported yet.");
}
};
}
public List subList(int fromIndex, int toIndex) {
return new LightArrayList(this, fromIndex, toIndex);
}
// Comparison and hashing
/**
* Compares the specified object with this list for equality. Returns
* {@code true} if and only if the specified object is also a list, both
* lists have the same size, and all corresponding pairs of elements in
* the two lists are equal. (Two elements {@code e1} and
* {@code e2} are equal if {@code (e1==null ? e2==null :
* e1.equals(e2))}.) In other words, two lists are defined to be
* equal if they contain the same elements in the same order.
*
* This implementation first checks if the specified object is this
* list. If so, it returns {@code true}; if not, it checks if the
* specified object is a list. If not, it returns {@code false}; if so,
* it iterates over both lists, comparing corresponding pairs of elements.
* If any comparison returns {@code false}, this method returns
* {@code false}. If either iterator runs out of elements before the
* other it returns {@code false} (as the lists are of unequal length);
* otherwise it returns {@code true} when the iterations complete.
*
* @param o the object to be compared for equality with this list
* @return {@code true} if the specified object is equal to this list
*/
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
}
if (!(o instanceof List)) {
return false;
}
ListIterator e1 = listIterator();
ListIterator e2 = ((List) o).listIterator();
while (e1.hasNext() && e2.hasNext()) {
E o1 = e1.next();
Object o2 = e2.next();
if (!(o1 == null ? o2 == null : o1.equals(o2))) {
return false;
}
}
return !(e1.hasNext() || e2.hasNext());
}
/**
* Returns the hash code value for this list.
*
* This implementation uses exactly the code that is used to define the
* list hash function in the documentation for the {@link List#hashCode}
* method.
*
* @return the hash code value for this list
*/
@Override
public int hashCode() {
int hashCode = 1;
Iterator i = iterator();
while (i.hasNext()) {
E obj = i.next();
hashCode = 31 * hashCode + (obj == null ? 0 : obj.hashCode());
}
return hashCode;
}
public void ensureCapacity(int newCapacity) {
int requiredLength = offset + newCapacity;
int diff = requiredLength - array.length;
if (diff <= 0) {
return;
}
if (offset >= diff) {
for(int i = 0; i < size; i++) {
array[i] = array[i + offset];
}
offset = 0;
} else {
int newLength = Math.max(newCapacity, size * 2);
Object[] newArray = new Object[newLength];
System.arraycopy(array, 0, newArray, 0, size);
array = newArray;
}
}
}