Implementation code for a simple dynamic array

The following is my dynamic array implementation of the source code, for reference only, please correct me:

Import java.util.*;p Ublic class My_list implements collection{/**************************************************** Test module//Main method, test with public static void main (String [] args) {/*my_list ma = new my_list ();//Test Add Method Ma.add ("abc"); Ma.add ("ASDFJ"); System.out.println (Ma.size ());//Test Get Method System.out.println (Ma.get (0)); System.out.println (Ma.get (1));//test Add Method two Ma.add (1, "changed value"); System.out.println (Ma.get (1));//test AddAll method List lis = new ArrayList (); Lis.add ("1"); Lis.add ("2"); Lis.add ("3"); Ma.addall (1,lis); System.out.println ("Length after execution of AddAll" + ma.size ()); System.out.println ("The fourth element after executing addall is" + ma.get (3));//test clear function//ma.clear ();//system.out.println (" The number of elements after the clear function executes (+ ma.size ());//test contains Method System.out.println ("Does it contain 1 strings?"). "+ Ma.contains (" 1 ")); System.out.println ("Does it contain 23 strings?") "+ Ma.contains");//lis.add ("ASDDFJ");//test Containsall Method System.out.println ("Ma contains all elements of the LIS? "+ Ma.containsall (LIS));//test Equals method my_list Lis2 = new My_list (); Lis2.add (" abc "); Lis2.add (" 123 "); Lis2.add (" Me and You "); My_list Lis3 = new My_list (); Lis3.add ("abc"); Lis3.add ("123"); Lis3.add ("I He"); Boolean b3 = Lis2.equals (LIS3); SYSTEM.OUT.PRINTLN (B3);//test indexOf method//lis.add (null);//int index_firstnull = Lis.indexof (null); Lis.add (" Asdjsdfaasdaa "); Lis.add (null); System.out.println ("3 first occurrence index is" + Lis.indexof ("3"));//test Lastindexoflis.add (NULL); Lis.add ("Me and You"); Lis.add (null); Lis.add ("3");  System.out.println ("Last show me and your Place" + Lis.lastindexof ("Me and You"));//Test IsEmptySystem.out.println ("Lis.isempty? "+ lis.isempty ()); My_list lis_isempty = new My_list ();  System.out.println ("Lis_isempty.isempty? "+ lis_isempty.isempty ());//Test RemoveSystem.out.println (" The length of the LIS before remove is "+ lis.size ()); System.out.println ("Remove, the value of index = 2 is" + Lis.get (2)); System.out.println ("Remove", the value of index = 6 is "+ lis.get (6)"),//lis.remove (null),//lis.remove (1); System.out.println ("The length of the LIS after remove is" + lis.size ()); System.out.println ("Remove, the value of index = 1 is" + lis.get (1)); System.out.println ("Remove, the value of index = 4 is" + Lis.get (4)); *///removeallTest my_list lis = new My_list () Lis.add ("1"); Lis.add ("2"); Lis.add ("3"); Lis.add ("Me and You"); Lis.add (null); Lis.add ("4"); Lis.add ("5"); Lis.add ("6");/*system.out.println ("The length of the LIS before RemoveAll is" + lis.size ()); System.out.println ("Before RemoveAll, the value of index = 1 is" + lis.get (1)); List Lis_removeall = new ArrayList (), Lis_removeall.add ("Me and You"), Lis_removeall.add ("3"); Lis_removeall.add (null); Lis.removeall (Lis_removeall);//system.out.println ("Before RemoveAll, the value of index = 6 is" + lis.get (6));; System.out.println ("The length of the LIS after RemoveAll" + lis.size ()); System.out.println ("After RemoveAll, the value of index = 3 is" + Lis.get (3)); System.out.println ("RemoveAll", the value of index = 4 is "+ Lis.get (4)"), *///method Retainall Test/*list Lis_retainall = new ArrayList (); Lis_retainall.add ("1"); Lis_retainall.add ("2"); Lis_retainall.add ("Me and You"); Lis_retainall.add ("null");//lis_ Retainall.add (); SYSTEM.OUT.PRINTLN ("Size of the LIS before executing the Retainall method =" + lis.size ()); Lis.retainall (Lis_retainall); SYSTEM.OUT.PRINTLN ("Size of the LIS after executing the Retainall method =" + lis.size ()); System.out.println ("Finished Retainall method after the value of the LIS output = "); System.out.println (Lis.get (2)); *///set method Test/*lis.set (2, "Soga"); System.out.println ("Index 2 value replaced after" + Lis.get (2)); Test of//sublist method my_list ml = new my_list (); ml = lis.sublist (2,4); SYSTEM.OUT.PRINTLN ("sublist returns the object length =" + ml.size ()); System.out.println ("Where the value of index 1 is =" + ml.get (1)); *//*//test toarrayobject [] ob_test1 = new object[]{"2", "4", "Akjsdf", "Me and You", Null};object [] ob = Lis.toarray (Ob_test1); System.out.println ("ToArray length is" + ob.length); System.out.println ("The first value of the returned array is" + ob[0]); *///Iterative method Test/*iterator it = Lis.iterator (); while (It.hasnext ()) { System.out.println (It.next ()); It.remove ();//it.remove ();} SYSTEM.OUT.PRINTLN ("size after iteration =" + lis.size ()); *///returns the hash value method Test int has = Lis.hashcode (); SYSTEM.OUT.PRINTLN ("List hash value is" + has);} /********************************************************************///my_list code/** member Variable */object [] Object = null ;//initial array length int len = 10;//defines the length of each increment int addlen = 10;//Dynamic array current element number private int size;//construction method Public My_list () {object = new object [len];size = 0;} /** The following is the implementation of CollEction method *///add Method A public boolean Add (Object OB) {Boolean RTN = false;//determines the number of current dynamic array objects if (size = = Object.length) {// Corresponding total length growth len = len + 10;//If the current array is full, re-put it in another array//define an array to store the current array value object [] Object_before = Object;object = new Object[len ];for (int i = 0;i<size;i++) {Object[i] = object_before[i];} Perform add operation object[size] = ob;size++;} Else{object[size] = ob;size++;} RTN = True;return Rtn;} Add method Two, index out of range throws exception public void Add (int index,object ob) {if (index<0| | index>size-1) {New RuntimeException ("Indexoutofboundsexception");} Else{object[index] = OB;}} AddAll method Public boolean addall (int index,collection c) {Boolean RTN = false;if (index<0| | index>size-1) {throw new RuntimeException ("Indexoutofboundsexception");} else if (c==null) {throw new RuntimeException ("NullPointerException");} else{for (int i = 0;i<c.size (); i++) {Add (C.toarray () [i]);} RTN = true;} return RTN;} public boolean AddAll (Collection c) {Boolean RTN = False;int Size_before = size;for (int i = 0;i<c.toarray (). length;i++) { Add (C.toaRray () [i]);} if (size_before! = size) {RTN = true;} return RTN;} Remove all elements public void clear () {for (int i = 0;i<size;i++) {Object[i] = 0;} size = 0;} Determines whether to include the specified element public boolean contains (Object ob) {Boolean RTN = false;for (int i = 0;i<size;i++) {if (OB = = null) {if (object[ I] = = null) {RTN = True;break;}} Else{if (Ob.equals (Object[i])) {RTN = True;break;}}} return RTN;} Determines whether to include all elements of Collection public boolean containsall (Collection c) {for (int i = 0;i<c.size (); i++) {if (!contains ( C.toarray () [i]) {return false;}} return true;} The Equals method public boolean equals (Object ob) {Boolean RTN = true;//First determines whether the object is a list if (Ob.getclass (). GetName (). Equals ("My_ List ")) {//To determine whether the lengths are consistent if (((my_list) OB). Size () ==size) {//To determine if the corresponding position corresponds to the element is equal for (int i = 0;i<size;i++) {if (!) ( ((my_list) OB). get (i). Equals (Object[i])) {return false;}} Else{rtn = false;}} Else{rtn = false;} return RTN;} Get method, out of range throw exception public Object get (int index) {Object RTN = null;if (index<0| | index>size-1) {throw new ArrayIndexOutOfBoundsException ("Indexoutofboundsexception");} ElSe{rtn = Object[index];} return RTN;} Returns the hash code value of the table (not implemented) public int hashcode () {int RTN = 0;int Hashcode = 1;iterator i = Iterator (), while (I.hasnext ()) {Object obj = I.next (); hashcode = 31*hashcode + (obj==null? 0:obj.hashcode ());} RTN = Hashcode;return Rtn;} Returns the index of the first occurrence of the element that does not exist, returns -1public int indexOf (Object ob) {int RTN = -1;//Determines whether the element in Object and list is compatible for (int i = 0;i<size;i++) {if (Object[i] = = null) {if (OB = = null) {return i;}} Else{if (Object[i].equals (ob)) {return i;}}} return RTN;} Returns the location of the last occurrence of this element public int lastIndexOf (Object ob) {int RTN = -1;for (int i = size-1;i>=0;i--) {if (object[i] = = null) {if (ob = = null) {return i;}} Else{if (Object[i].equals (ob)) {return i;}}} return RTN;} Determines whether the list contains elements public boolean IsEmpty () {Boolean RTN = true;if (size! = 0) {Rtn = false;} return RTN;} Returns an iterator that iterates in the appropriate order public Iterator Iterator () {Iterator RTN = Null;rtn = new My_iterator (this); return RTN;} Removes an element that returns the removed element if the passed-in index value goes out of range throws an exception to public Object remove (int index) {Object RTN = null;if (index<0| | Index>=size) {throw new RuntimEexception ("Indexoutofboundsexception");} ELSE{RTN = object[index];for (int i = index;i<size-1;i++) {Object[i] = object[i+1];} size--;} return RTN;} public boolean remove (Object ob) {boolean RTN = False;int index = indexOf (OB), if (index!=-1) {Remove (index), Rtn = true;} return RTN;} Remove all elements (problem start) public boolean removeall (Collection c) {Boolean RTN = false;//stores the current size value, which is used to determine if the list has elements that have changed int size_ before = Size;object [] Ob_toarray = C.toarray (); for (int i = 0;i<c.size (); i++) {remove (Ob_toarray[i]);} Because when C is the object itself, it is in the process of being changed, so if (this = = null && c = = NULL) is processed separately | | This.equals (c)) {clear ();} Determine if the elements in the table have changed if (Size_before = = size) {RTN = true;} return RTN;} Keep elements in list (code quality issues) (question) public boolean retainall (Collection c) {Boolean RTN = false;// Defines an reshape variable that stores the current Siez so that it can be used to determine whether the value of the list has changed int size_before = Size;object [] Ob_toarray = C.toarray (); for (int i = 0;i<size;i++) {f or (int j = 0;j<ob_toarray.length;j++) {if (object[i]==null) {if (ob_toarray[j]==null) {break;}} Else{if (Object[i].equals (Ob_toarray[j])) {break;}} if (j==ob_toarray.length-1) {//does not find the corresponding element after traversal, executes removeremove (i);//Because the distribution of elements in the original dynamic array occurs before the remove, so i--i--;}}} if (size_before!=size) {RTN = true;} return RTN;} Replace element, return previous element public Object set (int index,object ob) {Object RTN = Null;rtn = Object[index];object[index] = Ob;return RTN;} Size () returns the number of elements in the list public int size () {return size;} Returns elements from FromIndex to Toindex, before including the public my_list sublist (int fromindex,int toindex) {my_list RTN = null;if ((fromIndex >toindex) | | (fromindex<0) | | (toindex>size-1)) {throw new RuntimeException ("Indexoutofboundsexception");} Else{rtn = new My_list (); for (int i = fromindex;i<toindex;i++) {Rtn.add (Get (i));}} return RTN;} Returns all elements public object[] ToArray () {Object [] Rtn = NULL;RTN = Object;return Rtn;} Returns the element in the list public object[] ToArray (object [] ob) {Object [] Rtn = null; My_list ml = new My_list (), for (int i = 0;i<ob.length;i++) {if (contains (Ob[i])) {Ml.add (ob[i]);}} RTN = Ml.toarray (); return RTN;}} /*************************************************************************///iteratorsImplementation class My_iterator implements Iterator{my_list ml = null;object [] Object = null;//Define Constructor public my_iterator (My_list ml) {this.ml = Ml;object = Ml.toarray ();} /** The following is a method for implementing the Iterator Interface */public Boolean Hasnext () {Boolean RTN = True;if (point> (Ml.size ()-1)) {RTN = false;} return RTN;} Defines a pointer variable that is used to store the current cursor at next when private int point = 0;public object Next () {//each time the next method is called, the pointer variable is pointed to the initial position Object RTN = null;if ( Point> (Ml.size ()-1)) {throw new RuntimeException ("Nosuchelementexception");} Else{rtn = Object[point];p oint++;remove_canused = true;} return RTN;} Defines a Boolean variable to mark if remove has been invoked, and the variable is initialized to True after the next method call and is initialized to falsprivate Boolean remove_canused = False after remove is called; public void Remove () {///determines if the current point is consistent with if (remove_canused) {ml.remove (point-1);//Minus one here because the pointer variable has been increased since the next operation above/ Because the order of the list corresponding to the action after remove has also changed, the pointer correspondingly follows the 1point--;} Else{throw new RuntimeException ("IllegalStateException");} remove_canused = false;}}

Code is a bit long, you need to refer to the shortcomings of the point please correct!

Implementation code for a simple dynamic array