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- /*
- Copyright (c) 2008 Health Market Science, Inc.
-
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- This library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with this library; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
- USA
-
- You can contact Health Market Science at info@healthmarketscience.com
- or at the following address:
-
- Health Market Science
- 2700 Horizon Drive
- Suite 200
- King of Prussia, PA 19406
- */
-
- package com.healthmarketscience.jackcess;
-
- import java.io.IOException;
- import java.util.Collections;
- import java.util.List;
-
-
- /**
- * Simple implementation of an Access table index
- * @author Tim McCune
- */
- public class SimpleIndexData extends IndexData
- {
-
- static final DataPage NEW_ROOT_DATA_PAGE =
- new SimpleDataPage(0, true, Collections.<Entry>emptyList());
-
-
- /** data for the single index page. if this data came from multiple pages,
- the index is read-only. */
- private SimpleDataPage _dataPage;
-
- public SimpleIndexData(Table table, int number, int uniqueEntryCount,
- int uniqueEntryCountOffset)
- {
- super(table, number, uniqueEntryCount, uniqueEntryCountOffset);
- }
-
- @Override
- protected void updateImpl() throws IOException {
- writeDataPage(_dataPage);
- }
-
- @Override
- protected void readIndexEntries()
- throws IOException
- {
- // find first leaf page
- int nextPageNumber = getRootPageNumber();
- SimpleDataPage indexPage = null;
- while(true) {
- indexPage = new SimpleDataPage(nextPageNumber);
- readDataPage(indexPage);
-
- if(!indexPage.isLeaf()) {
- // FIXME we can't modify this index at this point in time
- setReadOnly();
-
- // found another node page
- if(!indexPage.getEntries().isEmpty()) {
- nextPageNumber = indexPage.getEntries().get(0).getSubPageNumber();
- } else {
- // try tail page
- nextPageNumber = indexPage.getChildTailPageNumber();
- }
- indexPage = null;
- } else {
- // found first leaf
- break;
- }
- }
-
- // save the first leaf page
- _dataPage = indexPage;
- nextPageNumber = indexPage.getNextPageNumber();
- _dataPage.setNextPageNumber(INVALID_INDEX_PAGE_NUMBER);
- indexPage = null;
-
- // read all leaf pages.
- while(nextPageNumber != INVALID_INDEX_PAGE_NUMBER) {
-
- // FIXME we can't modify this index at this point in time
- setReadOnly();
-
- // found another one
- indexPage = new SimpleDataPage(nextPageNumber);
- readDataPage(indexPage);
-
- // since we read all the entries in sort order, we can insert them
- // directly into the entries list
- _dataPage.getEntries().addAll(indexPage.getEntries());
- int totalSize = (_dataPage.getTotalEntrySize() +
- indexPage.getTotalEntrySize());
- _dataPage.setTotalEntrySize(totalSize);
- nextPageNumber = indexPage.getNextPageNumber();
- }
-
- // check the entry order, just to be safe
- List<Entry> entries = _dataPage.getEntries();
- for(int i = 0; i < (entries.size() - 1); ++i) {
- Entry e1 = entries.get(i);
- Entry e2 = entries.get(i + 1);
- if(e1.compareTo(e2) > 0) {
- throw new IOException("Unexpected order in index entries, " +
- e1 + " is greater than " + e2);
- }
- }
- }
-
- @Override
- protected DataPage findDataPage(Entry entry)
- throws IOException
- {
- return _dataPage;
- }
-
- @Override
- protected DataPage getDataPage(int pageNumber)
- throws IOException
- {
- throw new UnsupportedOperationException();
- }
-
- /**
- * Simple implementation of a DataPage
- */
- private static final class SimpleDataPage extends DataPage {
- private final int _pageNumber;
- private boolean _leaf;
- private int _nextPageNumber;
- private int _totalEntrySize;
- private int _childTailPageNumber;
- private List<Entry> _entries;
-
- private SimpleDataPage(int pageNumber) {
- this(pageNumber, false, null);
- }
-
- private SimpleDataPage(int pageNumber, boolean leaf, List<Entry> entries)
- {
- _pageNumber = pageNumber;
- _leaf = leaf;
- _entries = entries;
- }
-
- @Override
- public int getPageNumber() {
- return _pageNumber;
- }
-
- @Override
- public boolean isLeaf() {
- return _leaf;
- }
- @Override
- public void setLeaf(boolean isLeaf) {
- _leaf = isLeaf;
- }
-
- @Override
- public int getPrevPageNumber() { return 0; }
- @Override
- public void setPrevPageNumber(int pageNumber) {
- // ignored
- }
- @Override
- public int getNextPageNumber() {
- return _nextPageNumber;
- }
- @Override
- public void setNextPageNumber(int pageNumber) {
- _nextPageNumber = pageNumber;
- }
- @Override
- public int getChildTailPageNumber() {
- return _childTailPageNumber;
- }
- @Override
- public void setChildTailPageNumber(int pageNumber) {
- _childTailPageNumber = pageNumber;
- }
-
- @Override
- public int getTotalEntrySize() {
- return _totalEntrySize;
- }
- @Override
- public void setTotalEntrySize(int totalSize) {
- _totalEntrySize = totalSize;
- }
- @Override
- public byte[] getEntryPrefix() {
- return EMPTY_PREFIX;
- }
- @Override
- public void setEntryPrefix(byte[] entryPrefix) {
- // ignored
- }
-
- @Override
- public List<Entry> getEntries() {
- return _entries;
- }
-
- @Override
- public void setEntries(List<Entry> entries) {
- _entries = entries;
- }
-
- @Override
- public void addEntry(int idx, Entry entry) {
- _entries.add(idx, entry);
- _totalEntrySize += entry.size();
- }
-
- @Override
- public void removeEntry(int idx) {
- Entry oldEntry = _entries.remove(idx);
- _totalEntrySize -= oldEntry.size();
- }
-
- }
-
- }
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