/*
* Copyright 2014 The Skfiy Open Association.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.skfiy.typhon.util;
import java.util.AbstractList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
/**
*
* @author Kevin Zou <kevinz@skfiy.org>
* @param <E>
*/
public class SortedList<E> extends AbstractList<E>
implements List<E>, Cloneable, java.io.Serializable {
/**
* Default initial capacity.
*/
private static final int DEFAULT_CAPACITY = 10;
/**
* Shared empty array instance used for empty instances.
*/
private static final Object[] EMPTY_ELEMENTDATA = {};
/**
* The maximum size of array to allocate. Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in OutOfMemoryError: Requested array size
* exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* The array buffer into which the elements of the ArrayList are stored. The capacity of the
* ArrayList is the length of this array buffer. Any empty ArrayList with elementData ==
* EMPTY_ELEMENTDATA will be expanded to DEFAULT_CAPACITY when the first element is added.
*/
private transient Object[] elementData;
/**
* The size of the SortedList (the number of elements it contains).
*
* @serial
*/
private int size;
private Comparator<E> comparator;
/**
* Constructs an empty list with an initial capacity of ten.
*/
public SortedList() {
this.elementData = EMPTY_ELEMENTDATA;
}
/**
* Constructs an empty list with the specified initial capacity.
*
* @param initialCapacity the initial capacity of the list
* @throws IllegalArgumentException if the specified initial capacity is negative
*/
public SortedList(int initialCapacity) {
this(initialCapacity, null);
}
/**
*
* @param comparator
*/
public SortedList(Comparator<E> comparator) {
this.elementData = EMPTY_ELEMENTDATA;
this.comparator = comparator;
}
/**
*
* @param initialCapacity
* @param comparator
*/
public SortedList(int initialCapacity, Comparator<E> comparator) {
if (initialCapacity < 0) {
throw new IllegalArgumentException("Illegal Capacity: "
+ initialCapacity);
}
this.elementData = new Object[initialCapacity];
this.comparator = comparator;
}
/**
*
* @return
*/
public Comparator<E> getComparator() {
return comparator;
}
/**
*
* @param comparator
*/
public void setComparator(Comparator<E> comparator) {
this.comparator = comparator;
}
/**
* Trims the capacity of this <tt>ArrayList</tt> instance to be the list's current size. An
* application can use this operation to minimize the storage of an <tt>ArrayList</tt> instance.
*/
public void trimToSize() {
modCount++;
if (size < elementData.length) {
elementData = Arrays.copyOf(elementData, size);
}
}
/**
* Increases the capacity of this <tt>ArrayList</tt> instance, if necessary, to ensure that it
* can hold at least the number of elements specified by the minimum capacity argument.
*
* @param minCapacity the desired minimum capacity
*/
public void ensureCapacity(int minCapacity) {
int minExpand = (elementData != EMPTY_ELEMENTDATA)
// any size if real element table
? 0
// larger than default for empty table. It's already supposed to be
// at default size.
: DEFAULT_CAPACITY;
if (minCapacity > minExpand) {
ensureExplicitCapacity(minCapacity);
}
}
@Override
public int size() {
return size;
}
@Override
public boolean isEmpty() {
return size == 0;
}
/**
* Returns <tt>true</tt> if this list contains the specified element. More formally, returns
* <tt>true</tt> if and only if this list contains at least one element <tt>e</tt> such that
* <tt>(o==null ? e==null : o.equals(e))</tt>.
*
* @param o element whose presence in this list is to be tested
* @return <tt>true</tt> if this list contains the specified element
*/
@Override
public boolean contains(Object o) {
return indexOf(o) >= 0;
}
/**
* Returns the index of the first occurrence of the specified element in this list, or -1 if
* this list does not contain the element. More formally, returns the lowest index <tt>i</tt>
* such that
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>, or -1 if there is
* no such index.
*/
@Override
public int indexOf(Object o) {
if (o == null) {
for (int i = 0; i < size; i++) {
if (elementData[i] == null) {
return i;
}
}
} else {
for (int i = 0; i < size; i++) {
if (o.equals(elementData[i])) {
return i;
}
}
}
return -1;
}
/**
* Returns the index of the last occurrence of the specified element in this list, or -1 if this
* list does not contain the element. More formally, returns the highest index <tt>i</tt> such
* that
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>, or -1 if there is
* no such index.
*/
@Override
public int lastIndexOf(Object o) {
if (o == null) {
for (int i = size - 1; i >= 0; i--) {
if (elementData[i] == null) {
return i;
}
}
} else {
for (int i = size - 1; i >= 0; i--) {
if (o.equals(elementData[i])) {
return i;
}
}
}
return -1;
}
/**
* Returns an array containing all of the elements in this list in proper sequence (from first
* to last element); the runtime type of the returned array is that of the specified array. If
* the list fits in the specified array, it is returned therein. Otherwise, a new array is
* allocated with the runtime type of the specified array and the size of this list.
*
* <p>
* If the list fits in the specified array with room to spare (i.e., the array has more elements
* than the list), the element in the array immediately following the end of the collection is
* set to
* <tt>null</tt>. (This is useful in determining the length of the list <i>only</i> if the
* caller knows that the list does not contain any null elements.)
*
* @param a the array into which the elements of the list are to be stored, if it is big enough;
* otherwise, a new array of the same runtime type is allocated for this purpose.
* @return an array containing the elements of the list
* @throws ArrayStoreException if the runtime type of the specified array is not a supertype of
* the runtime type of every element in this list
* @throws NullPointerException if the specified array is null
*/
@Override
public <T> T[] toArray(T[] a) {
if (a.length < size) // Make a new array of a's runtime type, but my contents:
{
return (T[]) Arrays.copyOf(elementData, size, a.getClass());
}
System.arraycopy(elementData, 0, a, 0, size);
if (a.length > size) {
a[size] = null;
}
return a;
}
// Positional Access Operations
E elementData(int index) {
return (E) elementData[index];
}
/**
* Returns the element at the specified position in this list.
*
* @param index index of the element to return
* @return the element at the specified position in this list
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
@Override
public E get(int index) {
rangeCheck(index);
return elementData(index);
}
/**
* Appends the specified element to the end of this list.
*
* @param e element to be appended to this list
* @return <tt>true</tt> (as specified by {@link Collection#add})
*/
@Override
public boolean add(E e) {
ensureCapacityInternal(size + 1); // Increments modCount!!
int cmp;
// split comparator and comparable paths
Comparator<? super E> cpr = comparator;
if (cpr != null) {
for (int i = 0; i < size; i++) {
E v = elementData(i);
cmp = cpr.compare(e, v);
if (cmp < 0) {
System.arraycopy(elementData, i, elementData, i + 1, (size - i));
elementData[i] = e;
size++;
return true;
}
}
} else {
Comparable<? super E> v = (Comparable<? super E>) e;
for (int i = 0; i < size; i++) {
E ev = elementData(i);
cmp = v.compareTo(ev);
if (cmp < 0) {
System.arraycopy(elementData, i, elementData, i + 1, (size - i));
elementData[i] = e;
size++;
return true;
}
}
}
elementData[size++] = e;
return true;
}
/**
* Removes the element at the specified position in this list. Shifts any subsequent elements to
* the left (subtracts one from their indices).
*
* @param index the index of the element to be removed
* @return the element that was removed from the list
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
@Override
public E remove(int index) {
rangeCheck(index);
modCount++;
E oldValue = elementData(index);
int numMoved = size - index - 1;
if (numMoved > 0) {
System.arraycopy(elementData, index + 1, elementData, index, numMoved);
}
elementData[--size] = null; // clear to let GC do its work
return oldValue;
}
/**
* Removes the first occurrence of the specified element from this list, if it is present. If
* the list does not contain the element, it is unchanged. More formally, removes the element
* with the lowest index
* <tt>i</tt> such that
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>
* (if such an element exists). Returns <tt>true</tt> if this list contained the specified
* element (or equivalently, if this list changed as a result of the call).
*
* @param o element to be removed from this list, if present
* @return <tt>true</tt> if this list contained the specified element
*/
@Override
public boolean remove(Object o) {
if (o == null) {
for (int index = 0; index < size; index++) {
if (elementData[index] == null) {
fastRemove(index);
return true;
}
}
} else {
for (int index = 0; index < size; index++) {
if (o.equals(elementData[index])) {
fastRemove(index);
return true;
}
}
}
return false;
}
/*
* Private remove method that skips bounds checking and does not
* return the value removed.
*/
private void fastRemove(int index) {
modCount++;
int numMoved = size - index - 1;
if (numMoved > 0) {
System.arraycopy(elementData, index + 1, elementData, index, numMoved);
}
elementData[--size] = null; // clear to let GC do its work
}
/**
* Removes all of the elements from this list. The list will be empty after this call returns.
*/
@Override
public void clear() {
modCount++;
// clear to let GC do its work
for (int i = 0; i < size; i++) {
elementData[i] = null;
}
size = 0;
}
/**
* Appends all of the elements in the specified collection to the end of this list, in the order
* that they are returned by the specified collection's Iterator. The behavior of this operation
* is undefined if the specified collection is modified while the operation is in progress.
* (This implies that the behavior of this call is undefined if the specified collection is this
* list, and this list is nonempty.)
*
* @param c collection containing elements to be added to this list
* @return <tt>true</tt> if this list changed as a result of the call
* @throws NullPointerException if the specified collection is null
*/
@Override
public boolean addAll(Collection<? extends E> c) {
for (Iterator<? extends E> it = c.iterator(); it.hasNext();) {
add(it.next());
}
return true;
}
/**
* Removes from this list all of the elements whose index is between {@code fromIndex},
* inclusive, and {@code toIndex}, exclusive. Shifts any succeeding elements to the left
* (reduces their index). This call shortens the list by {@code (toIndex - fromIndex)} elements.
* (If {@code toIndex==fromIndex}, this operation has no effect.)
*
* @throws IndexOutOfBoundsException if {@code fromIndex} or {@code toIndex} is out of range ({@code fromIndex < 0 ||
* fromIndex >= size() ||
* toIndex > size() ||
* toIndex < fromIndex})
*/
@Override
protected void removeRange(int fromIndex, int toIndex) {
modCount++;
int numMoved = size - toIndex;
System.arraycopy(elementData, toIndex, elementData, fromIndex,
numMoved);
// clear to let GC do its work
int newSize = size - (toIndex - fromIndex);
for (int i = newSize; i < size; i++) {
elementData[i] = null;
}
size = newSize;
}
/**
* Checks if the given index is in range. If not, throws an appropriate runtime exception. This
* method does *not* check if the index is negative: It is always used immediately prior to an
* array access, which throws an ArrayIndexOutOfBoundsException if index is negative.
*/
private void rangeCheck(int index) {
if (index >= size) {
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
}
/**
* A version of rangeCheck used by add and addAll.
*/
private void rangeCheckForAdd(int index) {
if (index > size || index < 0) {
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
}
/**
* Constructs an IndexOutOfBoundsException detail message. Of the many possible refactorings of
* the error handling code, this "outlining" performs best with both server and client VMs.
*/
private String outOfBoundsMsg(int index) {
return "Index: " + index + ", Size: " + size;
}
/**
* Returns an array containing all of the elements in this list in proper sequence (from first
* to last element).
*
* <p>
* The returned array will be "safe" in that no references to it are maintained by this list.
* (In other words, this method must allocate a new array). The caller is thus free to modify
* the returned array.
*
* <p>
* This method acts as bridge between array-based and collection-based APIs.
*
* @return an array containing all of the elements in this list in proper sequence
*/
@Override
public Object[] toArray() {
return Arrays.copyOf(elementData, size);
}
/**
* Returns a shallow copy of this <tt>ArrayList</tt> instance. (The elements themselves are not
* copied.)
*
* @return a clone of this <tt>ArrayList</tt> instance
*/
@Override
public Object clone() {
try {
SortedList<E> v = (SortedList<E>) super.clone();
v.elementData = Arrays.copyOf(elementData, size);
v.modCount = 0;
return v;
} catch (CloneNotSupportedException e) {
// this shouldn't happen, since we are Cloneable
throw new InternalError();
}
}
private void ensureCapacityInternal(int minCapacity) {
if (elementData == EMPTY_ELEMENTDATA) {
minCapacity = Math.max(DEFAULT_CAPACITY, minCapacity);
}
ensureExplicitCapacity(minCapacity);
}
private void ensureExplicitCapacity(int minCapacity) {
modCount++;
// overflow-conscious code
if (minCapacity - elementData.length > 0) {
grow(minCapacity);
}
}
/**
* Increases the capacity to ensure that it can hold at least the number of elements specified
* by the minimum capacity argument.
*
* @param minCapacity the desired minimum capacity
*/
private void grow(int minCapacity) {
// overflow-conscious code
int oldCapacity = elementData.length;
int newCapacity = oldCapacity + (oldCapacity >> 1);
if (newCapacity - minCapacity < 0) {
newCapacity = minCapacity;
}
if (newCapacity - MAX_ARRAY_SIZE > 0) {
newCapacity = hugeCapacity(minCapacity);
}
// minCapacity is usually close to size, so this is a win:
elementData = Arrays.copyOf(elementData, newCapacity);
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
{
throw new OutOfMemoryError();
}
return (minCapacity > MAX_ARRAY_SIZE)
? Integer.MAX_VALUE
: MAX_ARRAY_SIZE;
}
}