/*
* This file is a part of Alchemy OS project.
* Copyright (C) 2011-2013, Sergey Basalaev <sbasalaev@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package alchemy.util;
/**
* List of elements backed by array.
* <p>
* Unlike <code>Vector</code> this class is not synchronized.
*
* @author Sergey Basalaev
*/
public final class ArrayList {
private Object[] elements;
private int size;
/** Creates new empty ArrayList with default capacity. */
public ArrayList() {
this(16);
}
/** Creates new empty ArrayList with given capacity. */
public ArrayList(int capacity) {
elements = new Object[capacity];
size = 0;
}
private void growBy(int count) {
int minCapacity = elements.length + count;
int newCapacity = (elements.length * 3) / 2 + 1;
if (newCapacity < minCapacity) newCapacity = minCapacity;
Object[] data = new Object[newCapacity];
System.arraycopy(elements, 0, data, 0, size);
elements = data;
}
/** Returns number of elements in this list. */
public int size() {
return size;
}
/** Returns true if this list contains no elements. */
public boolean isEmpty() {
return size == 0;
}
/** Removes all elements from this list. */
public void clear() {
for (int i=size-1; i>=0; i--) {
elements[i] = null;
}
size = 0;
}
/** Returns element at given index. */
public Object get(int index) {
if (index < 0 || index >= size)
throw new IndexOutOfBoundsException();
return elements[index];
}
/** Returns first element of this list. */
public Object first() {
if (size == 0) throw new IndexOutOfBoundsException();
return elements[0];
}
/** Returns last element of this list. */
public Object last() {
if (size == 0) throw new IndexOutOfBoundsException();
return elements[size-1];
}
/** Sets new value to the elements of this list. */
public void set(int index, Object e) {
if (index < 0 || index >= size)
throw new IndexOutOfBoundsException();
elements[index] = e;
}
/** Inserts element in given position of the list. */
public void insert(int index, Object e) {
if (index < 0 || index > size)
throw new IndexOutOfBoundsException();
if (elements.length == size)
growBy(1);
if (index < size)
System.arraycopy(elements, index, elements, index+1, size-index);
elements[index] = e;
size++;
}
/** Inserts elements from given array. */
public void insertFrom(int index, Object array, int ofs, int len) {
if (len < 0) len = Arrays.arrayLength(array);
if (len == 0) return;
if (elements.length < size + len)
growBy(len);
if (index < size)
System.arraycopy(elements, index, elements, index+len, size-index);
Arrays.arrayCopy(array, ofs, elements, index, len);
size += len;
}
/** Adds element to the end of the list. */
public void add(Object e) {
if (elements.length == size)
growBy(1);
elements[size] = e;
size++;
}
/** Adds elements from given array. */
public void addFrom(Object array, int ofs, int len) {
if (len < 0) len = Arrays.arrayLength(array);
if (len == 0) return;
if (elements.length < size + len)
growBy(len);
Arrays.arrayCopy(array, ofs, elements, size, len);
size += len;
}
/** Removes element from given position of the list. */
public void remove(int index) {
if (index < 0) index += size;
if (index < 0 || index >= size) throw new IndexOutOfBoundsException();
size--;
if (index < size)
System.arraycopy(elements, index+1, elements, index, size-index);
elements[size] = null;
}
/** Finds and removes given element. */
public boolean remove(Object e) {
int idx = indexOf(e, 0);
if (idx >= 0) remove(idx);
return idx >= 0;
}
/** Returns sublist of this list. */
public ArrayList getRange(int from, int to) {
if (from < 0) from += size;
if (to < 0) to += size;
int len = to-from;
ArrayList list = new ArrayList(len);
list.size = len;
System.arraycopy(elements, from, list.elements, 0, len);
return list;
}
/** Tests whether list contains given element. */
public boolean contains(Object e) {
return indexOf(e, 0) >= 0;
}
/**
* Returns index of the first occurence of given object
* after given index.
* Returns -1 if the list does not contain it.
*/
public int indexOf(Object e, int from) {
for (int index = from; index < size; index++) {
if (e == null ? elements[index] == null : e.equals(elements[index])) {
return index;
}
}
return -1;
}
/**
* Returns index of the first occurence of given object.
* Returns -1 if the list does not contain it.
*/
public int indexOf(Object e) {
return indexOf(e, 0);
}
/**
* Returns index of the last occurence of given object.
* Returns -1 if the list does not contain it.
*/
public int lastIndexOf(Object e) {
for (int index = size-1; index >= 0; index--) {
if (e == null ? elements[index] == null : e.equals(elements[index])) {
return index;
}
}
return -1;
}
/**
* Copies portion of this list into given array.
*
* @param from index of the first element to copy
* @param array object or promitive array to copy into
* @param offset offset in array to place first element
* @param len number of elements to copy
*/
public void copyInto(int from, Object array, int offset, int len) {
if (len < 0) len = Arrays.arrayLength(array);
if (len == 0) return;
if (from < 0 || from >= size || len > size || offset < 0 || offset + len > Arrays.arrayLength(array))
throw new IndexOutOfBoundsException();
Arrays.arrayCopy(elements, from, array, offset, len);
}
/** Copies contents of this list into given array. */
public void copyInto(Object array) {
copyInto(0, array, 0, size);
}
void buildString(ArrayList dejaVu, StringBuffer buf) {
if (dejaVu.indexOf(this, 0) >= 0) {
buf.append("[...]");
} else {
dejaVu.add(this);
buf.append('[');
for (int i=0; i<size; i++) {
if (i != 0) buf.append(", ");
Strings.buildString(elements[i], dejaVu, buf);
}
buf.append(']');
dejaVu.remove(this);
}
}
/** Returns string representation of this list. */
public String toString() {
StringBuffer buf = new StringBuffer();
buildString(new ArrayList(), buf);
return buf.toString();
}
}
免费AI编程助手
【list】
