2 * Copyright (C) 2001, 2002 The Mir-coders group
4 * This file is part of Mir.
6 * Mir is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * Mir is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with Mir; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 * In addition, as a special exception, The Mir-coders gives permission to link
21 * the code of this program with the com.oreilly.servlet library, any library
22 * licensed under the Apache Software License, The Sun (tm) Java Advanced
23 * Imaging library (JAI), The Sun JIMI library (or with modified versions of
24 * the above that use the same license as the above), and distribute linked
25 * combinations including the two. You must obey the GNU General Public
26 * License in all respects for all of the code used other than the above
27 * mentioned libraries. If you modify this file, you may extend this exception
28 * to your version of the file, but you are not obligated to do so. If you do
29 * not wish to do so, delete this exception statement from your version.
34 import mir.storage.StorageObject;
35 import mir.storage.StorageObjectFailure;
36 import mir.util.RewindableIterator;
38 public class EntityBrowser implements RewindableIterator {
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40 private StorageObject storage;
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41 private String whereClause;
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42 private String orderByClause;
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43 private int batchSize;
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44 private int toFetch;
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45 private EntityList currentBatch;
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50 private int batchPosition;
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51 private int positionInBatch;
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53 public EntityBrowser(StorageObject aStorage, String aWhereClause, String anOrderByClause,
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54 int aBatchSize, int aLimit, int aSkip) throws StorageObjectFailure {
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57 whereClause=aWhereClause;
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58 orderByClause=anOrderByClause;
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59 batchSize=aBatchSize;
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66 public EntityBrowser(StorageObject aStorage,
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67 String aWhereClause, String anOrderByClause,
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68 int aBatchSize) throws StorageObjectFailure {
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69 this(aStorage, aWhereClause, anOrderByClause, aBatchSize, -1, 0);
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72 public void readCurrentBatch(int aSkip) throws StorageObjectFailure {
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73 currentBatch = storage.selectByWhereClause(whereClause, orderByClause, aSkip, batchSize);
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74 batchPosition = aSkip;
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75 positionInBatch = 0;
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78 public void rewind() {
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80 readCurrentBatch(skip);
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82 catch (Throwable t) {
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83 throw new RuntimeException(t.getMessage());
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87 public boolean hasNext() {
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89 if (limit>-1 && batchPosition+positionInBatch>=skip+limit)
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92 if (positionInBatch>=currentBatch.size() && currentBatch.hasNextBatch()) {
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93 readCurrentBatch(batchPosition+positionInBatch);
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96 return (positionInBatch<currentBatch.size());
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98 catch (Throwable t) {
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99 throw new RuntimeException(t.getMessage());
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103 public Object next() {
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106 Entity result = currentBatch.elementAt(positionInBatch);
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107 positionInBatch=positionInBatch+1;
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115 catch (Throwable t) {
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116 throw new RuntimeException(t.getMessage());
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120 public void remove() {
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121 throw new UnsupportedOperationException();
\r