92 * 93 * @author Josh Bloch 94 * @author Neal Gafter 95 * @see Collection 96 * @see List 97 * @see LinkedList 98 * @see Vector 99 * @since 1.2 100 */ 101 102 public class ArrayList extends AbstractList 103 implements List, RandomAccess, Cloneable, java.io.Serializable 104 { 105 private static final long serialVersionUID = 8683452581122892189L; 106 107 /** 108 * The array … 713 throw new ConcurrentModificationException(); 260 * or -1 if there is no such index. extends E> c) { 337 * allocated with the runtime type of the specified array and the size of 375 * Returns the element at the specified position in this list. 767 * Returns an iterator over the elements in this list in proper sequence. 857 public void set(E e) { 336 * specified array, it is returned therein. 133 } 784 762 public ListIterator listIterator() { 204 private void grow(int minCapacity) { 211 newCapacity = hugeCapacity(minCapacity); 946 E oldValue = ArrayList.this.elementData(offset + index); 357 public T[] toArray(T[] a) { HQ » Java Tutorial » Example Source Code » Java Array Examples » Loop through an ArrayList On this section we will be showing some java examples on how to iterate or loop through an arraylist. 10 *, 11 * This code is distributed in the hope that it will be useful, but WITHOUT We can insert a new element either at the end, or the specific position of the list: 530 Object[] a = c.toArray(); 531 int numNew = a.length; 607 /** 179 if (minCapacity > 0) 473 if (o == null) { Source code analysis of Java Collections Framework (2 – ArrayList) If you ask Java programmers what is the most commonly used data structure? 498 numMoved); GitHub Gist: instantly share code, notes, and snippets. 1027 throw new NoSuchElementException(); 966 this.modCount = parent.modCount; 48 * time cost. 782 int lastRet = -1; // index of last element returned; -1 if no such 585 modCount++; elementData = Arrays.copyOf(elementData, size, Object[].class); 1119 if (index < 0 || index > this.size) 991 public boolean addAll(int index, Collection toIndex) 732 for (int i=0; iThe returned list iterator is fail-fast. The new elements will appear 513 size = 0; 182 739 * The specified index indicates the first element that would be 183 private void ensureCapacityInternal(int minCapacity) { An ArrayList is backed by an Array. 488 129 if (initialCapacity < 0) 1062 throw new IllegalStateException(); 657 * @see Collection#contains(Object) 596 /** 665 int r = 0, w = 0; 360 return (T[]) Arrays.copyOf(elementData, size, a.getClass()); 361 System.arraycopy(elementData, 0, a, 0, size); 764 } That’s what remove method does internally in the ArrayList class in Java. 396 public E set(int index, E element) { 829 cursor = index; 568 } 841 return cursor - 1; 987 public boolean addAll(Collection= elementData.length) Inner Workings of ArrayList and LinkedList. 802 public void remove() { 936 this.parent = parent; 265 if (elementData[i]==null) 1003 925 ") > toIndex(" + toIndex + ")"); 373 816 697 * (each an Object) in the proper order. 730. 264 for (int i = 0; i < size; i++) 297 * elements themselves are not copied.) queue implementation in java using arraylist . I think there are no more than these three:ArrayList，HashMapandHashSet。 This time, we will analyze the source code of ArrayList. 948 return oldValue; 628 * @param c collection containing elements to be removed from this list 54 * Note that this implementation is not synchronized. 135 /** 670 elementData[w++] = elementData[r]; 671 } finally { 1097 throw new ConcurrentModificationException(); 808 ArrayList.this.remove(lastRet); 62 * 1000 this.size += cSize; 1001 return true; 684 size = w; 847 int i = cursor - 1; 202 * @param minCapacity the desired minimum capacity 899 * 911 * @throws IllegalArgumentException {@inheritDoc} 69 *
190 /**. This article describes how to implement a list data structure in Java. 1028 Object[] elementData = ArrayList.this.elementData; 463 * i such that ArrayList(CollectionList interface, 126 */ 142 /** 447 modCount++; 125 * is negative 113 /** 7 * published by the Free Software Foundation. 818 if (modCount != expectedModCount) 49 * 306 v.modCount = 0; 834 } Write a program to implement your own ArrayList class. Conclusion 1118 private void rangeCheckForAdd(int index) { 551 * @throws NullPointerException if the specified collection is null */ private transient E [] elementData; /** * The size of the ArrayList (the number of elements it contains). 459 /** 1086 944 rangeCheck(index); 110 */, 111 private transient Object[] elementData; If you remove any element from an array then all the subsequent elements are to be shifted to fill the gap created by the removed element. 439 * 903 * 42 * 955 } This means that ArrayList internally contains an array of values and a 524 * 495 int numMoved = size - index - 1; 968 } 758 *
The returned list iterator is fail-fast. 329 return Arrays.copyOf(elementData, size); This point is already covered in the section how add and remove methods work in ArrayList. 315 * Returns an array containing all of the elements in this list 910 * @throws IndexOutOfBoundsException {@inheritDoc}. 820 }, 821 } To add an edge to the adjacency list we have the following code : So that’s how internally ArrayList keeps on growing dynamically. 648 * @param c collection containing elements to be retained in this list Internally ArrayList in Java uses array to store its element. 174 * specified by the minimum capacity argument. 892 *
This method eliminates the need for explicit range operations (of 147 * @param c the collection whose elements are to be placed into this list 165 int oldCapacity = elementData.length; 105 private static final long serialVersionUID = 8683452581122892189L; You can however create an Object[] whose elements are Strings, and you can see from the successful cast and use of a specific String method that their runtime type is String. 1060 public void remove() {, 1061 if (lastRet < 0) 25 715 386 435 /** If the size of the current elements (including the new element to be added to the ArrayList) is greater than the maximum size of the array then increase the size of array. 185 // overflow-conscious code 908 * a fashion that iterations in progress may yield incorrect results.) 277 * in this list, or -1 if this list does not contain the element. This can be found in the weiss\util folder. 380 */, 381 public E get(int index) { 940 this.modCount = ArrayList.this.modCount; 941 } 444 public E remove(int index) { 403 Shifts the element currently at that position (if any) and 13 * FITNESS FOR A PARTICULAR PURPOSE. 1073 } 366 Java example source code file: Graph.java (arraylist, edge, graph, illegalargumentexception, list, ... this graph implementation may or may not allow * multiple edges between any two adjacent nodes. There is an implementation of a large subset of java.util in package weiss.util. 750 throw new IndexOutOfBoundsException("Index: "+index); 751 return new ListItr(index); 436 * Removes the element at the specified position in this list. 242 /** 645 * specified collection. This application has a provision to insert, modify, delete, and display patient records such as name, age, sex, address, illness, hospital charges. * The capacity of the ArrayList is the length of this array buffer. 66 * unsynchronized access to the list:
916 } * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. 583 */ 740 * returned by an initial call to {@link ListIterator#next next}. The caller is thus free to modify the returned array. 590 // Let gc do its work. 942 The scrollable items are collected at a List (ArrayList… 914 subListRangeCheck(fromIndex, toIndex, size); 177 */ 1115 throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); 1 /* Also the elementData array is changed to have the new capacity, elements from the old array are also copied to the new array. 489 /* 324 * 219 return (minCapacity > MAX_ARRAY_SIZE) ? 208 if (newCapacity - minCapacity < 0) 724 // Read in size, and any hidden stuff 631 * is incompatible with the specified collection 655 * (optional), extends E> c) { 1083 throw new ConcurrentModificationException(); 512 445 rangeCheck(index); Previous Post: Export Maven Project as jar file including all dependencies. 290 return i; 291 } 687 } 952 rangeCheck(index); extends E> c) { 900 * Similar idioms may be constructed for {@link #indexOf(Object)} and, 901 * {@link #lastIndexOf(Object)}, and all of the algorithms in the 723 throws java.io.IOException, ClassNotFoundException { 726 33 * used internally to store the list. 757 * 716 } 584 protected void removeRange(int fromIndex, int toIndex) { 1088 checkForComodification(); 59 * resizes the backing array; merely setting the value of an element is not extends E> c) {, 151 elementData = c.toArray(); 14 * version 2 for more details (a copy is included in the LICENSE file that 130 throw new IllegalArgumentException("Illegal Capacity: "+, 131 initialCapacity); 870 checkForComodification(); 871 319 * maintained by this list. 1104 } 508 543 * in the list in the order that they are returned by the 67 * List list = Collections.synchronizedList(new ArrayList(...)); 1029 if (offset + i >= elementData.length) (In other words, this method must allocate 1047 throw new ConcurrentModificationException(); 253 } 893 * the sort that commonly exist for arrays). 801 4. 58 * any operation that adds or deletes one or more elements, or explicitly 233 /** 123 * @param initialCapacity the initial capacity of the list 960 }, 961 959 return this.size; 1059 Any operation that expects ArrayList Implementation In Java - Java Code Korner ArrayList Implementation In Java Array List is a class present in java.util package and is a part of Java Collecation Framework. 579 * ({@code fromIndex < 0 || 434 If something is missing or you have something to share about the topic please write a comment. ... if you say "How do you implement a calculator in Java" that means "How do you write a calculator program in Java?" 216 private static int hugeCapacity(int minCapacity) { 120 /**, 121 * Constructs an empty list with the specified initial capacity. 261 */ 155 elementData = Arrays.copyOf(elementData, size, Object[].class); 573 * Shifts any succeeding elements to the left (reduces their index). 303 @SuppressWarnings("unchecked") 659 public boolean retainAll(Collection c) { 1117 If the capacity is exhausted a new array is created with 50% more capacity than the previous one. Oracle designates this 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 1070 } catch (IndexOutOfBoundsException ex) {, 1071 throw new ConcurrentModificationException(); 866 } 313 407 * @param e element to be appended to this list 263 if (o == null) { ArrayList is initialized by the size. 394 * @throws IndexOutOfBoundsException {@inheritDoc} 898 * list.subList(from, to).clear(); Implementation of an Adjacency List. 549 * @return true if this list changed as a result of the call 591 int newSize = size - (toIndex-fromIndex); 46 * its capacity grows automatically. 163 public void trimToSize() { 370 E elementData(int index) {, 371 return (E) elementData[index]; 521 * is in progress. 363 a[size] = null; 677 size - r); 817 final void checkForComodification() { 1106 } extends E> c) { 980 checkForComodification(); 981 parent.removeRange(parentOffset + fromIndex, 815 } 780 private class Itr implements Iterator {, 781 int cursor; // index of next element to return 835 194 * OutOfMemoryError: Requested array size exceeds VM limit 566 size += numNew; 1096 } catch (IndexOutOfBoundsException ex) { If you see the ArrayList internal implementation in Java, everytime add () method is called it is ensured that ArrayList has required capacity. 397 rangeCheck(index); 509 // Let gc do its work 288 for (int i = size-1; i >= 0; i--) 633 * @throws NullPointerException if this list contains a null element and the 539 * Inserts all of the elements in the specified collection into this 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. 145 * iterator. 497 System.arraycopy(elementData, index+1, elementData, index, 1005 return listIterator(); 339 * 777 /** 332 /** 788 971 rangeCheck(index); 298 * 26, 31 * null. 301 public Object clone() { 1112 675 System.arraycopy(elementData, r, 976 return result; 143 * Constructs a list containing the elements of the specified 335 * array is that of the specified array. 564 List interface ArrayListIt is mainly realizedListInterface and inherits theAbstractListAbstract class, let’s take … 979 protected void removeRange(int fromIndex, int toIndex) { eval(ez_write_tag([[250,250],'knpcode_com-leader-2','ezslot_8',143,'0','0']));When add() method is called initially there is a check to ensure the capacity. ArrayList is implemented using a dynamic array data structure to store objects, hence it can grow or shrink whenever you add or remove elements from it. 322 * This method acts as bridge between array-based and collection-based 853 cursor = i; This is one of the most important knowledge in dealing with list and arrays on how to loop for each elements. 997 checkForComodification(); 433 } 753 354 * @throws NullPointerException if the specified array is null 316 * in proper sequence (from first to last element). 1004 public Iterator iterator() { 475 if (elementData[index] == null) { 558 ensureCapacityInternal(size + numNew); // Increments modCount 737 * Returns a list iterator over the elements in this list (in proper 136 * Constructs an empty list with an initial capacity of ten. 166 if (size < oldCapacity) { 347 * @param a the array into which the elements of the list are to Learn how your comment data is processed. 922 throw new IndexOutOfBoundsException("toIndex = " + toIndex); 830 }, 831 245 * at least one element e such that 998 parent.addAll(parentOffset + index, c); (This implies that the behavior of this call is 523 * list is nonempty.) 575 * (If {@code toIndex==fromIndex}, this operation has no effect.) 252 return indexOf(o) >= 0; 1098 } 863 ArrayList.this.set(lastRet, e); The add operation runs in amortized constant time,
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