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yacy_search_server/source/de/anomic/kelondro/blob/BLOBArray.java

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// kelondroBLOBArray.java
// (C) 2008 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 19.08.2008 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate: 2006-04-02 22:40:07 +0200 (So, 02 Apr 2006) $
// $LastChangedRevision: 1986 $
// $LastChangedBy: orbiter $
//
// LICENSE
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package de.anomic.kelondro.blob;
import java.io.File;
import java.io.IOException;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.TreeMap;
import java.util.concurrent.CopyOnWriteArrayList;
import de.anomic.kelondro.order.ByteOrder;
import de.anomic.kelondro.order.CloneableIterator;
import de.anomic.kelondro.order.DateFormatter;
import de.anomic.kelondro.order.NaturalOrder;
import de.anomic.kelondro.order.MergeIterator;
public class BLOBArray implements BLOB {
/*
* This class implements a BLOB using a set of kelondroBLOBHeap objects
* In addition to a kelondroBLOBHeap this BLOB can delete large amounts of data using a given time limit.
* This is realized by creating separate BLOB files. New Files are created when either
* - a given time limit is reached
* - a given space limit is reached
* To organize such an array of BLOB files, the following file name structure is used:
* <BLOB-Name>/<YYYYMMDDhhmm>.blob
* That means all BLOB files are inside a directory that has the name of the BLOBArray.
* To delete content that is out-dated, one special method is implemented that deletes content by a given
* time-out. Deletions are not made automatically, they must be triggered using this method.
*/
public static final long oneMonth = 1000L * 60L * 60L * 24L * 365L / 12L;
public static final long oneGigabyte = 1024 * 1024 * 1024;
private int keylength;
private ByteOrder ordering;
private File heapLocation;
private long fileAgeLimit;
private long fileSizeLimit;
private long repositoryAgeMax;
private long repositorySizeMax;
private List<blobItem> blobs;
private String blobSalt;
private int buffersize;
public BLOBArray(
final File heapLocation,
final String blobSalt,
final int keylength,
final ByteOrder ordering,
final int buffersize) throws IOException {
this.keylength = keylength;
this.blobSalt = blobSalt;
this.ordering = ordering;
this.buffersize = buffersize;
this.heapLocation = heapLocation;
this.fileAgeLimit = oneMonth;
this.fileSizeLimit = oneGigabyte;
this.repositoryAgeMax = Long.MAX_VALUE;
this.repositorySizeMax = Long.MAX_VALUE;
// check existence of the heap directory
if (heapLocation.exists()) {
if (!heapLocation.isDirectory()) throw new IOException("the BLOBArray directory " + heapLocation.toString() + " does not exist (is blocked by a file with same name)");
} else {
if(!heapLocation.mkdirs()) throw new IOException("the BLOBArray directory " + heapLocation.toString() + " does not exist (can not be created)");
}
// register all blob files inside this directory
String[] files = heapLocation.list();
Date d;
TreeMap<Long, blobItem> sortedItems = new TreeMap<Long, blobItem>();
BLOB oneBlob;
File f;
long time, maxtime = 0;
// first find maximum time: the file with this time will be given a write buffer
for (int i = 0; i < files.length; i++) {
if (files[i].length() >= 19 && files[i].endsWith(".blob")) {
try {
d = DateFormatter.parseShortSecond(files[i].substring(0, 14));
time = d.getTime();
if (time > maxtime) maxtime = time;
} catch (ParseException e) {continue;}
}
}
for (int i = 0; i < files.length; i++) {
if (files[i].length() >= 19 && files[i].endsWith(".blob")) {
try {
d = DateFormatter.parseShortSecond(files[i].substring(0, 14));
f = new File(heapLocation, files[i]);
time = d.getTime();
oneBlob = (time == maxtime && buffersize > 0) ? new BLOBHeap(f, keylength, ordering, buffersize) : new BLOBHeapModifier(f, keylength, ordering);
sortedItems.put(Long.valueOf(time), new blobItem(d, f, oneBlob));
} catch (ParseException e) {continue;}
}
}
// read the blob tree in a sorted way and write them into an array
blobs = new CopyOnWriteArrayList<blobItem>();
for (blobItem bi : sortedItems.values()) {
blobs.add(bi);
}
}
/**
* add a blob file to the array.
* note that this file must be generated with a file name from newBLOB()
* @param location
* @throws IOException
*/
public void mountBLOB(File location) throws IOException {
Date d;
try {
d = DateFormatter.parseShortSecond(location.getName().substring(0, 14));
} catch (ParseException e) {
throw new IOException("date parse problem with file " + location.toString() + ": " + e.getMessage());
}
BLOB oneBlob = (buffersize > 0) ? new BLOBHeap(location, keylength, ordering, buffersize) : new BLOBHeapModifier(location, keylength, ordering);
blobs.add(new blobItem(d, location, oneBlob));
}
public void unmountBLOB(File location) {
Iterator<blobItem> i = this.blobs.iterator();
blobItem b;
while (i.hasNext()) {
b = i.next();
if (b.location.equals(location)) {
i.remove();
b.blob.close();
return;
}
}
}
public File unmountOldestBLOB() {
if (this.blobs.size() == 0) return null;
blobItem b = this.blobs.remove(0);
b.blob.close();
return b.location;
}
/**
* return the number of BLOB files in this array
* @return
*/
public int entries() {
return this.blobs.size();
}
/**
* generate a new BLOB file name with a given date.
* This method is needed to generate a file name that matches to the name structure that is needed for parts of the array
* @param creation
* @return
*/
public File newBLOB(Date creation) {
return new File(heapLocation, DateFormatter.formatShortSecond(creation) + "." + blobSalt + ".blob");
}
public String name() {
return this.heapLocation.getName();
}
public void setMaxAge(long maxAge) {
this.repositoryAgeMax = maxAge;
this.fileAgeLimit = Math.min(oneMonth, maxAge / 10);
}
public void setMaxSize(long maxSize) {
this.repositorySizeMax = maxSize;
this.fileSizeLimit = Math.min(oneGigabyte, maxSize / 10);
}
private void executeLimits() {
// check if storage limits are reached and execute consequences
if (blobs.size() == 0) return;
// age limit:
while (blobs.size() > 0 && System.currentTimeMillis() - blobs.get(0).creation.getTime() - this.fileAgeLimit > this.repositoryAgeMax) {
// too old
blobItem oldestBLOB = blobs.remove(0);
oldestBLOB.blob.close();
oldestBLOB.location.delete();
}
// size limit
while (blobs.size() > 0 && length() > this.repositorySizeMax) {
// too large
blobItem oldestBLOB = blobs.remove(0);
oldestBLOB.blob.close();
oldestBLOB.location.delete();
}
}
/*
* return the size of the repository
*/
public long length() {
long s = 0;
for (int i = 0; i < blobs.size(); i++) s += blobs.get(i).location.length();
return s;
}
public ByteOrder ordering() {
return this.ordering;
}
private class blobItem {
Date creation;
File location;
BLOB blob;
public blobItem(Date creation, File location, BLOB blob) {
this.creation = creation;
this.location = location;
this.blob = blob;
}
public blobItem(int buffer) throws IOException {
// make a new blob file and assign it in this item
this.creation = new Date();
this.location = newBLOB(this.creation);
this.blob = (buffer == 0) ? new BLOBHeapModifier(location, keylength, ordering) : new BLOBHeap(location, keylength, ordering, buffer);
}
}
/**
* ask for the length of the primary key
* @return the length of the key
*/
public int keylength() {
return this.keylength;
}
/**
* clears the content of the database
* @throws IOException
*/
public void clear() throws IOException {
for (blobItem bi: blobs) bi.blob.clear();
blobs.clear();
}
/**
* ask for the number of entries
* @return the number of entries in the table
*/
public int size() {
int s = 0;
for (blobItem bi: blobs) s += bi.blob.size();
return s;
}
/**
* iterator over all keys
* @param up
* @param rotating
* @return
* @throws IOException
*/
public CloneableIterator<byte[]> keys(boolean up, boolean rotating) throws IOException {
assert rotating = false;
final List<CloneableIterator<byte[]>> c = new ArrayList<CloneableIterator<byte[]>>(blobs.size());
final Iterator<blobItem> i = blobs.iterator();
while (i.hasNext()) {
c.add(i.next().blob.keys(up, rotating));
}
return MergeIterator.cascade(c, this.ordering, MergeIterator.simpleMerge, up);
}
/**
* iterate over all keys
* @param up
* @param firstKey
* @return
* @throws IOException
*/
public CloneableIterator<byte[]> keys(boolean up, byte[] firstKey) throws IOException {
final List<CloneableIterator<byte[]>> c = new ArrayList<CloneableIterator<byte[]>>(blobs.size());
final Iterator<blobItem> i = blobs.iterator();
while (i.hasNext()) {
c.add(i.next().blob.keys(up, firstKey));
}
return MergeIterator.cascade(c, this.ordering, MergeIterator.simpleMerge, up);
}
/**
* check if a specific key is in the database
* @param key the primary key
* @return
* @throws IOException
*/
public boolean has(byte[] key) {
for (blobItem bi: blobs) if (bi.blob.has(key)) return true;
return false;
}
/**
* retrieve the whole BLOB from the table
* @param key the primary key
* @return
* @throws IOException
*/
public byte[] get(byte[] key) throws IOException {
byte[] b;
for (blobItem bi: blobs) {
b = bi.blob.get(key);
if (b != null) return b;
}
return null;
}
/**
* get all BLOBs in the array.
* this is useful when it is not clear if an entry is unique in all BLOBs in this array.
* @param key
* @return
* @throws IOException
*/
public List<byte[]> getAll(byte[] key) throws IOException {
byte[] b;
ArrayList<byte[]> l = new ArrayList<byte[]>(blobs.size());
for (blobItem bi: blobs) {
b = bi.blob.get(key);
if (b != null) l.add(b);
}
return l;
}
/**
* retrieve the size of the BLOB
* @param key
* @return the size of the BLOB or -1 if the BLOB does not exist
* @throws IOException
*/
public long length(byte[] key) throws IOException {
long l;
for (blobItem bi: blobs) {
l = bi.blob.length(key);
if (l >= 0) return l;
}
return -1;
}
/**
* write a whole byte array as BLOB to the table
* @param key the primary key
* @param b
* @throws IOException
*/
public void put(byte[] key, byte[] b) throws IOException {
blobItem bi = (blobs.size() == 0) ? null : blobs.get(blobs.size() - 1);
if (bi == null)
System.out.println("bi == null");
else if (System.currentTimeMillis() - bi.creation.getTime() > this.fileAgeLimit)
System.out.println("System.currentTimeMillis() - bi.creation.getTime() > this.maxage");
else if (bi.location.length() > this.fileSizeLimit)
System.out.println("bi.location.length() > this.maxsize");
if ((bi == null) || (System.currentTimeMillis() - bi.creation.getTime() > this.fileAgeLimit) || (bi.location.length() > this.fileSizeLimit)) {
// add a new blob to the array
bi = new blobItem(buffersize);
blobs.add(bi);
}
assert bi.blob instanceof BLOBHeap;
bi.blob.put(key, b);
executeLimits();
}
/**
* replace a BLOB entry with another which must be smaller or same size
* @param key the primary key
* @throws IOException
*/
public int replace(byte[] key, Rewriter rewriter) throws IOException {
int d = 0;
for (blobItem bi: blobs) {
d += bi.blob.replace(key, rewriter);
}
return d;
}
/**
* remove a BLOB
* @param key the primary key
* @throws IOException
*/
public void remove(byte[] key) throws IOException {
for (blobItem bi: blobs) bi.blob.remove(key);
}
/**
* close the BLOB
*/
public void close() {
for (blobItem bi: blobs) bi.blob.close();
blobs.clear();
blobs = null;
}
public static void main(final String[] args) {
final File f = new File("/Users/admin/blobarraytest");
try {
//f.delete();
final BLOBArray heap = new BLOBArray(f, "test", 12, NaturalOrder.naturalOrder, 512 * 1024);
heap.put("aaaaaaaaaaaa".getBytes(), "eins zwei drei".getBytes());
heap.put("aaaaaaaaaaab".getBytes(), "vier fuenf sechs".getBytes());
heap.put("aaaaaaaaaaac".getBytes(), "sieben acht neun".getBytes());
heap.put("aaaaaaaaaaad".getBytes(), "zehn elf zwoelf".getBytes());
// iterate over keys
Iterator<byte[]> i = heap.keys(true, false);
while (i.hasNext()) {
System.out.println("key_b: " + new String(i.next()));
}
heap.remove("aaaaaaaaaaab".getBytes());
heap.remove("aaaaaaaaaaac".getBytes());
heap.put("aaaaaaaaaaaX".getBytes(), "WXYZ".getBytes());
heap.close();
} catch (final IOException e) {
e.printStackTrace();
}
}
}