Page MenuHomec4science
Files F79349451

BasicDB.java
No OneTemporary
Actions

File Metadata

Created
Sun, Aug 25, 23:20

BasicDB.java
View Options

/**
* Copyright (c) 2010 Yahoo! Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you
* may not use this file except in compliance with the License. You
* may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License. See accompanying
* LICENSE file.
*/
package com.yahoo.ycsb;
import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.LockSupport;
/**
* Basic DB that just prints out the requested operations, instead of doing them against a database.
*/
public class BasicDB extends DB
{
public static final String VERBOSE="basicdb.verbose";
public static final String VERBOSE_DEFAULT="true";
public static final String SIMULATE_DELAY="basicdb.simulatedelay";
public static final String SIMULATE_DELAY_DEFAULT="0";
public static final String RANDOMIZE_DELAY="basicdb.randomizedelay";
public static final String RANDOMIZE_DELAY_DEFAULT="true";
boolean verbose;
boolean randomizedelay;
int todelay;
public BasicDB()
{
todelay=0;
}
void delay()
{
if (todelay>0)
{
long delayNs;
if (randomizedelay) {
delayNs = TimeUnit.MILLISECONDS.toNanos(Utils.random().nextInt(todelay));
if (delayNs == 0) {
return;
}
}
else {
delayNs = TimeUnit.MILLISECONDS.toNanos(todelay);
}
long now = System.nanoTime();
final long deadline = now + delayNs;
do {
LockSupport.parkNanos(deadline - now);
} while ((now = System.nanoTime()) < deadline && !Thread.interrupted());
}
}
/**
* Initialize any state for this DB.
* Called once per DB instance; there is one DB instance per client thread.
*/
@SuppressWarnings("unchecked")
public void init()
{
verbose=Boolean.parseBoolean(getProperties().getProperty(VERBOSE, VERBOSE_DEFAULT));
todelay=Integer.parseInt(getProperties().getProperty(SIMULATE_DELAY, SIMULATE_DELAY_DEFAULT));
randomizedelay=Boolean.parseBoolean(getProperties().getProperty(RANDOMIZE_DELAY, RANDOMIZE_DELAY_DEFAULT));
if (verbose) synchronized(System.out)
{
System.out.println("***************** properties *****************");
Properties p=getProperties();
if (p!=null)
{
for (Enumeration e=p.propertyNames(); e.hasMoreElements(); )
{
String k=(String)e.nextElement();
System.out.println("\""+k+"\"=\""+p.getProperty(k)+"\"");
}
}
System.out.println("**********************************************");
}
}
static final ThreadLocal<StringBuilder> TL_STRING_BUILDER = new ThreadLocal<StringBuilder>() {
@Override
protected StringBuilder initialValue() {
return new StringBuilder();
}
};
static StringBuilder getStringBuilder() {
StringBuilder sb = TL_STRING_BUILDER.get();
sb.setLength(0);
return sb;
}
/**
* Read a record from the database. Each field/value pair from the result will be stored in a HashMap.
*
* @param table The name of the table
* @param key The record key of the record to read.
* @param fields The list of fields to read, or null for all of them
* @param result A HashMap of field/value pairs for the result
* @return Zero on success, a non-zero error code on error
*/
public Status read(String table, String key, Set<String> fields, HashMap<String,ByteIterator> result)
{
delay();
if (verbose)
{
StringBuilder sb = getStringBuilder();
sb.append("READ ").append(table).append(" ").append(key).append(" [ ");
if (fields!=null)
{
for (String f : fields)
{
sb.append(f).append(" ");
}
}
else
{
sb.append("<all fields>");
}
sb.append("]");
System.out.println(sb);
}
return Status.OK;
}
/**
* Perform a range scan for a set of records in the database. Each field/value pair from the result will be stored in a HashMap.
*
* @param table The name of the table
* @param startkey The record key of the first record to read.
* @param recordcount The number of records to read
* @param fields The list of fields to read, or null for all of them
* @param result A Vector of HashMaps, where each HashMap is a set field/value pairs for one record
* @return Zero on success, a non-zero error code on error
*/
public Status scan(String table, String startkey, int recordcount, Set<String> fields, Vector<HashMap<String,ByteIterator>> result)
{
delay();
if (verbose)
{
StringBuilder sb = getStringBuilder();
sb.append("SCAN ").append(table).append(" ").append(startkey).append(" ").append(recordcount).append(" [ ");
if (fields!=null)
{
for (String f : fields)
{
sb.append(f).append(" ");
}
}
else
{
sb.append("<all fields>");
}
sb.append("]");
System.out.println(sb);
}
return Status.OK;
}
/**
* Update a record in the database. Any field/value pairs in the specified values HashMap will be written into the record with the specified
* record key, overwriting any existing values with the same field name.
*
* @param table The name of the table
* @param key The record key of the record to write.
* @param values A HashMap of field/value pairs to update in the record
* @return Zero on success, a non-zero error code on error
*/
public Status update(String table, String key, HashMap<String,ByteIterator> values)
{
delay();
if (verbose)
{
StringBuilder sb = getStringBuilder();
sb.append("UPDATE ").append(table).append(" ").append(key).append(" [ ");
if (values!=null)
{
for (Map.Entry<String, ByteIterator> entry : values.entrySet())
{
sb.append(entry.getKey()).append("=").append(entry.getValue()).append(" ");
}
}
sb.append("]");
System.out.println(sb);
}
return Status.OK;
}
/**
* Insert a record in the database. Any field/value pairs in the specified values HashMap will be written into the record with the specified
* record key.
*
* @param table The name of the table
* @param key The record key of the record to insert.
* @param values A HashMap of field/value pairs to insert in the record
* @return Zero on success, a non-zero error code on error
*/
public Status insert(String table, String key, HashMap<String,ByteIterator> values)
{
delay();
if (verbose)
{
StringBuilder sb = getStringBuilder();
sb.append("INSERT ").append(table).append(" ").append(key).append(" [ ");
if (values!=null)
{
for (Map.Entry<String, ByteIterator> entry : values.entrySet())
{
sb.append(entry.getKey()).append("=").append(entry.getValue()).append(" ");
}
}
sb.append("]");
System.out.println(sb);
}
return Status.OK;
}
/**
* Delete a record from the database.
*
* @param table The name of the table
* @param key The record key of the record to delete.
* @return Zero on success, a non-zero error code on error
*/
public Status delete(String table, String key)
{
delay();
if (verbose)
{
StringBuilder sb = getStringBuilder();
sb.append("DELETE ").append(table).append(" ").append(key);
System.out.println(sb);
}
return Status.OK;
}
/**
* Short test of BasicDB
*/
/*
public static void main(String[] args)
{
BasicDB bdb=new BasicDB();
Properties p=new Properties();
p.setProperty("Sky","Blue");
p.setProperty("Ocean","Wet");
bdb.setProperties(p);
bdb.init();
HashMap<String,String> fields=new HashMap<String,String>();
fields.put("A","X");
fields.put("B","Y");
bdb.read("table","key",null,null);
bdb.insert("table","key",fields);
fields=new HashMap<String,String>();
fields.put("C","Z");
bdb.update("table","key",fields);
bdb.delete("table","key");
}*/
}

Event Timeline

c4science · Help