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1 /*
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2 File: HashParams.d
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3
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4 Originally written by Doug Lea and released into the public domain.
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5 Thanks for the assistance and support of Sun Microsystems Labs, Agorics
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6 Inc, Loral, and everyone contributing, testing, and using this code.
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7
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8 History:
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9 Date Who What
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10 24Sep95 dl@cs.oswego.edu Create from collections.d working file
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11
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12 */
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13
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14
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15 module tango.util.collection.model.HashParams;
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16
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17
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18 /**
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19 *
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20 * Base interface for hash table based collections.
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21 * Provides common ways of dealing with buckets and threshholds.
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22 * (It would be nice to share some of the code too, but this
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23 * would require multiple inheritance here.)
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24 *
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25 author: Doug Lea
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26 * @version 0.93
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27 *
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28 * <P> For an introduction to this package see <A HREF="index.html"> Overview </A>.
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29 *
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30 **/
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31
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32
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33 public interface HashParams
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34 {
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35
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36 /**
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37 * The default initial number of buckets of a non-empty HT
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38 **/
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39
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40 public static int defaultInitialBuckets = 31;
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41
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42 /**
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43 * The default load factor for a non-empty HT. When the proportion
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44 * of elements per buckets exceeds this, the table is resized.
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45 **/
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46
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47 public static float defaultLoadFactor = 0.75f;
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48
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49 /**
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50 * return the current number of hash table buckets
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51 **/
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52
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53 public int buckets();
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54
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55 /**
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56 * Set the desired number of buckets in the hash table.
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57 * Any value greater than or equal to one is OK.
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58 * if different than current buckets, causes a version change
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59 * Throws: IllegalArgumentException if newCap less than 1
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60 **/
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61
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62 public void buckets(int newCap);
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63
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64
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65 /**
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66 * Return the current load factor threshold
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67 * The Hash table occasionally checka against the load factor
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68 * resizes itself if it has gone past it.
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69 **/
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70
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71 public float thresholdLoadFactor();
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72
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73 /**
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74 * Set the current desired load factor. Any value greater than 0 is OK.
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75 * The current load is checked against it, possibly causing resize.
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76 * Throws: IllegalArgumentException if desired is 0 or less
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77 **/
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78
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79 public void thresholdLoadFactor(float desired);
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80 }
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