27 import java.util.*;
28
29 /**
30 * <b>WARNING:</b> This class is an implementation detail and is only
31 * public so that it can be used by two packages. You should NOT consider
32 * this public API.
33 * <p>
34 * <b>WARNING 2:</b> This is not a general purpose List implementation! It
35 * has a specific use and will not work correctly if you use it outside of
36 * its use.
37 * <p>
38 * A specialized ArrayList that caches its hashCode as well as overriding
39 * equals to avoid creating an Iterator. This class is useful in scenarios
40 * where the list won't change and you want to avoid the overhead of hashCode
41 * iterating through the elements invoking hashCode. This also assumes you'll
42 * only ever compare a BakedArrayList to another BakedArrayList.
43 *
44 * @author Scott Violet
45 */
46 @SuppressWarnings("serial") // JDK-implementation class
47 public class BakedArrayList extends ArrayList<Object> {
48 /**
49 * The cached hashCode.
50 */
51 private int _hashCode;
52
53 public BakedArrayList(int size) {
54 super(size);
55 }
56
57 public BakedArrayList(java.util.List<?> data) {
58 this(data.size());
59 for (int counter = 0, max = data.size(); counter < max; counter++){
60 add(data.get(counter));
61 }
62 cacheHashCode();
63 }
64
65 /**
66 * Caches the hash code. It is assumed you won't modify the list, or that
67 * if you do you'll call cacheHashCode again.
68 */
69 public void cacheHashCode() {
70 _hashCode = 1;
71 for (int counter = size() - 1; counter >= 0; counter--) {
72 _hashCode = 31 * _hashCode + get(counter).hashCode();
73 }
74 }
75
76 public int hashCode() {
77 return _hashCode;
78 }
79
80 public boolean equals(Object o) {
81 BakedArrayList list = (BakedArrayList)o;
82 int size = size();
83
84 if (list.size() != size) {
85 return false;
86 }
87 while (size-- > 0) {
88 if (!get(size).equals(list.get(size))) {
89 return false;
90 }
91 }
92 return true;
93 }
94 }
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27 import java.util.*;
28
29 /**
30 * <b>WARNING:</b> This class is an implementation detail and is only
31 * public so that it can be used by two packages. You should NOT consider
32 * this public API.
33 * <p>
34 * <b>WARNING 2:</b> This is not a general purpose List implementation! It
35 * has a specific use and will not work correctly if you use it outside of
36 * its use.
37 * <p>
38 * A specialized ArrayList that caches its hashCode as well as overriding
39 * equals to avoid creating an Iterator. This class is useful in scenarios
40 * where the list won't change and you want to avoid the overhead of hashCode
41 * iterating through the elements invoking hashCode. This also assumes you'll
42 * only ever compare a BakedArrayList to another BakedArrayList.
43 *
44 * @author Scott Violet
45 */
46 @SuppressWarnings("serial") // JDK-implementation class
47 public class BakedArrayList<E> extends ArrayList<E> {
48 /**
49 * The cached hashCode.
50 */
51 private int _hashCode;
52
53 public BakedArrayList(int size) {
54 super(size);
55 }
56
57 public BakedArrayList(java.util.List<? extends E> data) {
58 this(data.size());
59 for (int counter = 0, max = data.size(); counter < max; counter++){
60 add(data.get(counter));
61 }
62 cacheHashCode();
63 }
64
65 /**
66 * Caches the hash code. It is assumed you won't modify the list, or that
67 * if you do you'll call cacheHashCode again.
68 */
69 public void cacheHashCode() {
70 _hashCode = 1;
71 for (int counter = size() - 1; counter >= 0; counter--) {
72 _hashCode = 31 * _hashCode + get(counter).hashCode();
73 }
74 }
75
76 public int hashCode() {
77 return _hashCode;
78 }
79
80 public boolean equals(Object o) {
81 @SuppressWarnings("unchecked")
82 BakedArrayList<E> list = (BakedArrayList)o;
83 int size = size();
84
85 if (list.size() != size) {
86 return false;
87 }
88 while (size-- > 0) {
89 if (!get(size).equals(list.get(size))) {
90 return false;
91 }
92 }
93 return true;
94 }
95 }
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