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annotate src/org/dancres/blitz/config/ReadAhead.java @ 0:3dc0c5604566

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Initial checkin of blitz 2.0 fcs - no installer yet.
author Dan Creswell <dan.creswell@gmail.com>
date Sat, 21 Mar 2009 11:00:06 +0000
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3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff changeset
1 package org.dancres.blitz.config;
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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2
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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3 /**
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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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:
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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:
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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:
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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:
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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:
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9 *
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
diff changeset
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:
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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:
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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:
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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 changeset
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 changeset
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:
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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:
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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>
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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:
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22
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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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:
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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:
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25 }
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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26
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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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:
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29 }
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
parents:
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30 }