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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