Mercurial > hg > blitz_condensed
annotate src/org/dancres/blitz/config/ReadAhead.java @ 0:3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
author | Dan Creswell <dan.creswell@gmail.com> |
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date | Sat, 21 Mar 2009 11:00:06 +0000 |
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0
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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changeset
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1 package org.dancres.blitz.config; |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
2 |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
3 /** |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
4 * <p>When Blitz encounters a template Entry created via snapshot() it will |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
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5 * attempt a readahead from disk when there are no matches obtained from the |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
6 * cache. One can specify a global default readahead for all types using <code> |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
7 * entryReposReadahead</code> which can be overidden with individual |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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8 * <code>ReadAhead</code> <code>EntryConstraint</code>s.</p> |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
9 * |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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|
10 * <p>Specifying a readahead size of 0 disables readahead and is an enforced |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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|
11 * default for those Entry types tagged for FIFO operation. Specifying any |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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|
12 * other positive value causes Blitz to fault in up to <code>readahead</code> |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
13 * Entry's from disk which are likely to match the <code>snapshot</code>'d |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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14 * template.</p> |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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15 * |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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|
16 * <p>Readahead is useful in cold start situations where the cache will be |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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|
17 * empty and also in cases where swapping occurs but Entry's are accessed in |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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|
18 * groups via a snapshot template.</p> |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
19 */ |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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20 public class ReadAhead implements EntryConstraint { |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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21 private int theSize; |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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|
22 |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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23 public ReadAhead(int aSize) { |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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24 theSize = aSize; |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
25 } |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
26 |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
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27 public int getSize() { |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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28 return theSize; |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
29 } |
3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff
changeset
|
30 } |