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.DatabaseFailure;
37 import mir.storage.DatabaseExc;
38 import mir.util.RewindableIterator;
39 import multex.Failure;
41 public class EntityBrowser implements RewindableIterator {
43 private Database database;
44 private String mainTablePrefix;
45 private List extraTables;
46 private String whereClause;
47 private String orderByClause;
48 private int batchSize;
49 private EntityList currentBatch;
54 private int batchPosition;
55 private int positionInBatch;
57 public EntityBrowser(Database aDatabase, String aMainTablePrefix, List someExtraTables,
58 String aWhereClause, String anOrderByClause,
59 int aBatchSize, int aLimit, int aSkip) throws DatabaseFailure {
62 mainTablePrefix=aMainTablePrefix;
63 extraTables=someExtraTables;
64 whereClause=aWhereClause;
65 orderByClause=anOrderByClause;
73 public EntityBrowser(Database aDatabase, String aWhereClause, String anOrderByClause,
74 int aBatchSize, int aLimit, int aSkip) throws DatabaseFailure {
75 this(aDatabase, "", null, aWhereClause, anOrderByClause, aBatchSize, aLimit, aSkip);
78 public EntityBrowser(Database aDatabase,
79 String aWhereClause, String anOrderByClause,
80 int aBatchSize) throws DatabaseFailure {
81 this(aDatabase, aWhereClause, anOrderByClause, aBatchSize, -1, 0);
84 public void readCurrentBatch(int aSkip) throws DatabaseExc, DatabaseFailure {
85 currentBatch = database.selectByWhereClause(mainTablePrefix, extraTables,
86 whereClause, orderByClause, aSkip, batchSize);
87 batchPosition = aSkip;
91 public void rewind() {
93 readCurrentBatch(skip);
96 throw new Failure("Error while rewinging", t);
100 public boolean hasNext() {
102 if (limit>-1 && batchPosition+positionInBatch>=skip+limit)
105 if (positionInBatch>=currentBatch.size() && currentBatch.hasNextBatch()) {
106 readCurrentBatch(batchPosition+positionInBatch);
109 return (positionInBatch<currentBatch.size());
111 catch (Throwable t) {
112 throw new RuntimeException(t.getMessage());
116 public Object next() {
119 Entity result = currentBatch.elementAt(positionInBatch);
120 positionInBatch=positionInBatch+1;
126 catch (Throwable t) {
127 throw new RuntimeException(t.getMessage());
131 public void remove() {
132 throw new UnsupportedOperationException();