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 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(Collection 40 * run in linear time (roughly speaking). 138 public ArrayList() { 201 * 664 final Object[] elementData = this.elementData; If not, throws an appropriate 879 throw new ConcurrentModificationException(); 399 E oldValue = elementData(index); This is typically accomplished by, 61 * synchronizing on some object that naturally encapsulates the list. More formally, removes the element with the lowest index 359 // Make a new array of a's runtime type, but my contents: 406 * 881 } 880 }. 199 * Increases the capacity to ensure that it can hold at least the If you see the ArrayList internal implementation in Java, everytime add() method is called it is ensured that ArrayList has required capacity. 478 } 700 throws java.io.IOException{. 200 * number of elements specified by the minimum capacity argument. 490 * Private remove method that skips bounds checking and does not, 491 * return the value removed. 169 } 876 lastRet = -1; 237 */ Arraylist is a class in Java that implements the List interface. 18 * 2 along with this work; if not, write to the Free Software Foundation, 858 if (lastRet < 0) 598 * runtime exception. 300 */. In addition to implementing the List 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: 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 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