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 any library licensed under the Apache Software License,
22 * The Sun (tm) Java Advanced Imaging library (JAI), The Sun JIMI library
23 * (or with modified versions of the above that use the same license as the above),
24 * and distribute linked combinations including the two. You must obey the
25 * GNU General Public License in all respects for all of the code used other than
26 * the above mentioned libraries. If you modify this file, you may extend this
27 * exception to your version of the file, but you are not obligated to do so.
28 * If you do not wish to do so, delete this exception statement from your version.
33 import java.util.List;
35 import mir.storage.Database;
36 import mir.storage.StorageObjectFailure;
37 import mir.util.RewindableIterator;
38 import multex.Failure;
40 public class EntityBrowser implements RewindableIterator {
42 private Database database;
43 private String mainTablePrefix;
44 private List extraTables;
45 private String whereClause;
46 private String orderByClause;
47 private int batchSize;
48 private EntityList currentBatch;
53 private int batchPosition;
54 private int positionInBatch;
56 public EntityBrowser(Database aDatabase, String aMainTablePrefix, List someExtraTables,
57 String aWhereClause, String anOrderByClause,
58 int aBatchSize, int aLimit, int aSkip) throws StorageObjectFailure {
61 mainTablePrefix=aMainTablePrefix;
62 extraTables=someExtraTables;
63 whereClause=aWhereClause;
64 orderByClause=anOrderByClause;
72 public EntityBrowser(Database aDatabase, String aWhereClause, String anOrderByClause,
73 int aBatchSize, int aLimit, int aSkip) throws StorageObjectFailure {
74 this(aDatabase, "", null, aWhereClause, anOrderByClause, aBatchSize, aLimit, aSkip);
77 public EntityBrowser(Database aDatabase,
78 String aWhereClause, String anOrderByClause,
79 int aBatchSize) throws StorageObjectFailure {
80 this(aDatabase, aWhereClause, anOrderByClause, aBatchSize, -1, 0);
83 public void readCurrentBatch(int aSkip) throws StorageObjectFailure {
84 currentBatch = database.selectByWhereClause(mainTablePrefix, extraTables,
85 whereClause, orderByClause, aSkip, batchSize);
86 batchPosition = aSkip;
90 public void rewind() {
92 readCurrentBatch(skip);
95 throw new Failure("Error while rewinging", t);
99 public boolean hasNext() {
101 if (limit>-1 && batchPosition+positionInBatch>=skip+limit)
104 if (positionInBatch>=currentBatch.size() && currentBatch.hasNextBatch()) {
105 readCurrentBatch(batchPosition+positionInBatch);
108 return (positionInBatch<currentBatch.size());
110 catch (Throwable t) {
111 throw new RuntimeException(t.getMessage());
115 public Object next() {
118 Entity result = currentBatch.elementAt(positionInBatch);
119 positionInBatch=positionInBatch+1;
125 catch (Throwable t) {
126 throw new RuntimeException(t.getMessage());
130 public void remove() {
131 throw new UnsupportedOperationException();