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T.containsKey(key) true if the key is present in the tableHJ(J(^ .Accessing Table ContentsT.elements(), T.keys() return an Enumeration of the elements or keys stored in the table hasMoreElements() nextElement() Enumeration e = T.elements(); while ( e.hasMoreElements() ) elt = (myClass) e.nextElement();VY <!Y <!tY + /   ` ^WN̙f` ^WNff3` 999MMM` ^WNf` ff33` ff33` ^WN̙f>?" dd@(?zdd@ y x@" `  n?" dd@   @@``@n?" dd@  @@``PR   @ ` ` p>> ^V(    C XA@C:\WINDOWS\DESKTOP\JavaBack.jpg  s *v 0` v T Click to edit Master title style! !   c $v @ v RClick to edit Master text styles Second level Third level Fourth level Fifth level!     S  s *tv Tt v E* 2  s *v Tt  v G*(2  s *4v T@t v J11-*(2Z  B޽h))? ? ^WNff3 Javaxx.potd    ( &`    C XA@C:\WINDOWS\DESKTOP\JavaBack.jpg  s *$ @@  T Click to edit Master title style! !  c $ @   W#Click to edit Master subtitle style$ $  s *D T  E* 2^WN  s * T   G*(2^WN  s * T@  G*(2^WNZ  B޽h))? ? ^WNff3 0 @.(    0v P    Y*   0v     [* d  c $ ?    0Tv  @  RClick to edit Master text styles Second level Third level Fourth level Fifth level!     S  6v `P  v Y*   6v `   [* H  0޽h ? ̙33 04(      0v P    =*   0tv     ?*   6v `P   =*   64v `   ?* H  0޽h ? ̙33 x( K l  C Ľ PP   r  S $ ` p    00 pj VDr. Tim Margush Department of Mathematics and Computer Science The University of AkronW(2WH  0޽h ? ^WNff3   ( pj  l   C 0`   l   C D@  H   0޽h ? ^WNff3  ((  (l ( C 0`   l ( C d@  H ( 0޽h ? ^WNff3  0(  0l 0 C $0`   l 0 C @  H 0 0޽h ? ^WNff3L  4(  4l 4 C 0`   l 4 C D   l 4 C 8 @  H 4 0޽h ? ^WNff3  @( h @l @ C 0`   l @ C d@  H @ 0޽h ? ^WNff3L  `H(  Hl H C D0`   l H C    l H C 8 @  H H 0޽h ? ^WNff3   P( h Pl P C Tv0`   l P C v@  H P 0޽h ? ^WNff3 0 x( X R  3    ~  C  @    H  0޽h ? ̙33x 0 80$(  $R $ 3    6 $ C 了 @   NA hashtable is a storage structure for any type of object. A key is used to store and access objects. The (Key,Object) pairs are actually stored in the table in such a way so that they can be quickly retrieved based upon a key value. The hashtable uses the key s hashCode value to approximately locate the object. The equals method is used to determine an exact match. The objects used as keys must implement the hashCode and equals methods. The hashCode method must depend only on the key and return the same number for two keys that are equal. l     [H $ 0޽h ? ̙33 0 |t, ( Op ozhPz ,R , 3    z , C D @   Hashtables have a maximum capacity, but only use all of it if the load factor is 1. A load factor of .6 indicates the table is limited to 60% of its capacity. Smaller load factors mean greater speed, but require more memory. Load factors near 1 may cause very slow performance. When the number of items stored causes the table to exceed the stated load factor, the hashtable is automatically rehashed to a larger storage facility. The new capacity is twice the old (plus 1).$ b dH , 0޽h ? ̙33 0 ^V08(  8R 8 3    \ 8 C d @   (key, object) pairs are inserted into a hashtable via the put method. If another object was previously stored with the same key, the new object replaces the old. A reference to the old object is returned by put. The value null is returned if the key is new. The key s equals() method is used to determine if two keys are the same. The get method takes a key and locates the object stored in the hashtable with that key. If found, the object reference is returned (the object remains in the table). The return type for both methods is Object; you usually need to cast this to the appropriate class type.,( Y H 8 0޽h ? ̙33 0 xp <(  <R < 3    v < C  @   PA hashcode is an int that somehow represents an object. Different objects may have the same hashcode, but the best hashcode scheme will minimize this coincidence. If two objects are equal, they must (should( have the same hashcode. Strings have a hashcode method that satisfies this requirement. Objects are  equal when they have the same addresses (unless the equals method is overridden). The default Object hashCode value depends on an object s address. In general, two objects should be considered equal when their data memebrs are the same, not when they have the same address. Thus it is usually necessary to override the hashCode and equals methods for classes you create. G b  i` +H < 0޽h ? ̙33 0 x@D(  DR D 3    ~ D C ļ @    H D 0޽h ? ̙33 0 e]pL( @w LR L 3    vc L C d @  v These member functions provide information about the hashtable and its contents. The contains method is not very fast. It must sequentially search the table for a value that equals (using the equals method of the value class) the value specified. Hash tables are designed to access values quickly only when given a key. The containsKey method is fast. The String representation of a hashtable might be interesting to look at.>5  / !H L 0޽h ? ̙33 0 PTa(  TR T 3     T C $ @   oEnumerations provide a very general way to sequence through a collection of objects. Classes that implement the Enumeration interface provide two methods, hasMoreElements() and nextElement(). These are sufficient to write a loop that allows each object in a collection to be processed.6  bH T 0޽h ? ̙33r``*0|%4 E7RGb9MB;"=Q?@ABCDEFGHIJKLMNOPQRSTVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~Root EntrydO)Picturesg?Current UserSummaryInformation(URPowerPoint Document( iDocumentSummaryInformation8Root EntrydO)Уs ~Picturesg?Current UserMSummaryInformation(UR'_hUniversity UserUniversity User