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annotate src/org/dancres/blitz/entry/TupleLocator.java @ 35:6f68e94c1fb8 default tip

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Add CondensedStats monitoring utility, equivalent to vmstat
author Dominic Cleal <dominic-cleal@cdo2.com>
date Thu, 05 Aug 2010 11:07:25 +0100
parents 3dc0c5604566
children
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3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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1 package org.dancres.blitz.entry;
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2
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3 import java.io.IOException;
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4
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Dan Creswell <dan.creswell@gmail.com>
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5 import org.dancres.blitz.oid.OID;
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6
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7 /**
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8 All searches, whether they are performed in-memory or on-disk, result
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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9 in TupleLocators which are then used to iterate over the results.
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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10 Returned results are always UIDImpls which are then used to load
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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11 an appropriate EntrySleeve via SleeveCache (this ensures correct state is
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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12 maintained as the request to load a sleeve will make it's way into
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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13 an ArcCache then the WriteBuffer and then disk storage).
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14 */
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15 public interface TupleLocator {
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16 /**
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17 Invoke this to load the next matching Tuple.
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18
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19 @return <code>true</code> if there was a tuple, <code>false</code>
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20 otherwise
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21 */
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22 boolean fetchNext() throws IOException;
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23
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24 /**
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25 @return the OID of the tuple just fetched with
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26 <code>fetchNext</code>
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27 */
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28 OID getOID();
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29
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30 /**
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31 When you've finished with the TupleLocator instance, call release.
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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32 */
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33 void release() throws IOException;
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34 }