mirror of
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dc0c06e43d
redesign for better IO performance enhanced database seek-time by avoiding write operations at distant positions of a database file. until now, a USEDC counter was written at the head-section of a kelondroRecords database file (which is the basic data structure of all kelondro database files) to store the actual number of records that are contained in the database. Now, this value is computed from the database file size. This is either done only once at start-time, or continuously when run in asserts enabled. The counter is then updated only in RAM, and written at close of the file. If the close fails, the correct number can be computed from the file size, and if this is not equal to the stored number it is a strong evidence that YaCY was not shut down properly. To preserve consistency, the complete storage-routine had to be re-written. Another change enhances read of nodes in some cases, where the data-tail can be read together with the data-head. This saves another IO lookup during each DB node fetch. Includes also many small bugfixes. IF ANYTHING GOES WRONG, ALL YOUR DATA IS LOST: PLEASE MAKE A BACK-UP git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@3375 6c8d7289-2bf4-0310-a012-ef5d649a1542
216 lines
8.8 KiB
Java
216 lines
8.8 KiB
Java
// kelondroArray.java
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// ------------------
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// part of the Kelondro Database
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// (C) by Michael Peter Christen; mc@anomic.de
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// first published on http://www.anomic.de
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// Frankfurt, Germany, 2005
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// last major change: 20.06.2005
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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//
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// Using this software in any meaning (reading, learning, copying, compiling,
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// running) means that you agree that the Author(s) is (are) not responsible
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// for cost, loss of data or any harm that may be caused directly or indirectly
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// by usage of this softare or this documentation. The usage of this software
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// is on your own risk. The installation and usage (starting/running) of this
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// software may allow other people or application to access your computer and
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// any attached devices and is highly dependent on the configuration of the
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// software which must be done by the user of the software; the author(s) is
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// (are) also not responsible for proper configuration and usage of the
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// software, even if provoked by documentation provided together with
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// the software.
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//
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// Any changes to this file according to the GPL as documented in the file
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// gpl.txt aside this file in the shipment you received can be done to the
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// lines that follows this copyright notice here, but changes must not be
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// done inside the copyright notive above. A re-distribution must contain
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// the intact and unchanged copyright notice.
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// Contributions and changes to the program code must be marked as such.
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/*
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This class extends the kelondroRecords and adds a array structure
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*/
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package de.anomic.kelondro;
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import java.io.File;
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import java.io.IOException;
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public class kelondroFixedWidthArray extends kelondroRecords implements kelondroArray {
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// define the Over-Head-Array
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private static short thisOHBytes = 0; // our record definition does not need extra bytes
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private static short thisOHHandles = 0; // and no handles
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public kelondroFixedWidthArray(File file, kelondroRow rowdef, int intprops) throws IOException {
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// this creates a new array
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super(file, 0, 0, thisOHBytes, thisOHHandles, rowdef, intprops, rowdef.columns() /* txtProps */, 80 /* txtPropWidth */);
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if (!(super.fileExisted)) {
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for (int i = 0; i < intprops; i++) {
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setHandle(i, new Handle(NUL));
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}
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// store column description
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for (int i = 0; i < rowdef.columns(); i++) {
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try {super.setText(i, rowdef.column(i).toString().getBytes());} catch (IOException e) {}
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}
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}
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}
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public kelondroFixedWidthArray(kelondroRA ra, kelondroRow rowdef, int intprops) throws IOException {
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// this creates a new array
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super(ra, 0, 0, thisOHBytes, thisOHHandles, rowdef, intprops, rowdef.columns() /* txtProps */, 80 /* txtPropWidth */, false);
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for (int i = 0; i < intprops; i++) {
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setHandle(i, new Handle(0));
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}
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// store column description
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for (int i = 0; i < rowdef.columns(); i++) {
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try {super.setText(i, rowdef.column(i).toString().getBytes());} catch (IOException e) {}
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}
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}
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public static kelondroFixedWidthArray open(File file, kelondroRow rowdef, int intprops) {
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try {
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return new kelondroFixedWidthArray(file, rowdef, intprops);
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} catch (IOException e) {
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file.delete();
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try {
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return new kelondroFixedWidthArray(file, rowdef, intprops);
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} catch (IOException ee) {
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e.printStackTrace();
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ee.printStackTrace();
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System.exit(-1);
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return null;
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}
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}
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}
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public synchronized void set(int index, kelondroRow.Entry rowentry) throws IOException {
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// this writes a row without reading the row from the file system first
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// create a node at position index with rowentry
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Handle h = new Handle(index);
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newNode(h, (rowentry == null) ? null : rowentry.bytes(), 0, true).commit(CP_NONE);
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}
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public synchronized kelondroRow.Entry get(int index) throws IOException {
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return row().newEntry(getNode(new Handle(index), true).getValueRow());
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}
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protected synchronized int seti(int index, int value) throws IOException {
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int before = getHandle(index).hashCode();
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setHandle(index, new Handle(value));
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return before;
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}
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protected synchronized int geti(int index) {
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return getHandle(index).hashCode();
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}
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public synchronized int add(kelondroRow.Entry rowentry) throws IOException {
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Node n = newNode(rowentry.bytes());
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n.commit(CP_NONE);
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return n.handle().hashCode();
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}
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public synchronized void remove(int index) throws IOException {
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if (index >= (super.free() + super.size())) throw new IOException("remove: index " + index + " out of bounds " + (super.free() + super.size()));
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// get the node at position index
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Handle h = new Handle(index);
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Node n = getNode(h, false);
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// erase the row
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n.setValueRow(null);
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n.commit(CP_NONE);
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// mark row as deleted so it can be re-used
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deleteNode(h);
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}
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public void print() throws IOException {
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System.out.println("PRINTOUT of table, length=" + size());
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kelondroRow.Entry row;
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for (int i = 0; i < (super.free() + super.size()); i++) {
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System.out.print("row " + i + ": ");
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row = get(i);
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for (int j = 0; j < row.columns(); j++) System.out.print(((row.empty(j)) ? "NULL" : row.getColString(j, "UTF-8")) + ", ");
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System.out.println();
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}
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System.out.println("EndOfTable");
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}
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public static void main(String[] args) {
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//File f = new File("d:\\\\mc\\privat\\fixtest.db");
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File f = new File("/Users/admin/fixtest.db");
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kelondroRow rowdef = new kelondroRow("byte[] a-12, byte[] b-4", kelondroNaturalOrder.naturalOrder, 0);
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try {
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System.out.println("erster Test");
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f.delete();
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kelondroFixedWidthArray k = new kelondroFixedWidthArray(f, rowdef, 6);
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k.set(3, k.row().newEntry(new byte[][]{
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"test123".getBytes(), "abcd".getBytes()}));
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k.add(k.row().newEntry(new byte[][]{
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"test456".getBytes(), "efgh".getBytes()}));
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k.close();
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k = new kelondroFixedWidthArray(f, rowdef, 6);
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System.out.println(k.get(2).toString());
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System.out.println(k.get(3).toString());
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k.close();
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System.out.println("zweiter Test");
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f.delete();
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k = new kelondroFixedWidthArray(f, rowdef, 6);
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k.add(k.row().newEntry(new byte[][]{"a".getBytes(), "xxxx".getBytes()}));
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k.add(k.row().newEntry(new byte[][]{"b".getBytes(), "xxxx".getBytes()}));
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k.remove(0);
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k.add(k.row().newEntry(new byte[][]{"c".getBytes(), "xxxx".getBytes()}));
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k.add(k.row().newEntry(new byte[][]{"d".getBytes(), "xxxx".getBytes()}));
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k.add(k.row().newEntry(new byte[][]{"e".getBytes(), "xxxx".getBytes()}));
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k.add(k.row().newEntry(new byte[][]{"f".getBytes(), "xxxx".getBytes()}));
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k.remove(0);
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k.remove(1);
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k.print();
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k.print(true);
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k.close();
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System.out.println("dritter Test");
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f.delete();
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k = new kelondroFixedWidthArray(f, rowdef, 6);
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for (int i = 1; i <= 200; i = i * 2) {
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for (int j = 0; j < i*2; j++) {
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k.add(k.row().newEntry(new byte[][]{(Integer.toString(i) + "-" + Integer.toString(j)).getBytes(), "xxxx".getBytes()}));
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}
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for (int j = 0; j < i; j++) {
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k.remove(j);
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}
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}
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k.print();
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k.print(true);
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k.close();
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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}
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