Java DB类代码示例

import com.yahoo.ycsb.DB; //导入依赖的package包/类
public void doTransactionRead(DB db)
{
	//choose a random key
	int keynum = nextKeynum();
	
	String keyname = buildKeyName(keynum);
	
	HashSet<String> fields=null;

	if (!readallfields)
	{
		//read a random field  
		String fieldname="field"+fieldchooser.nextString();

		fields=new HashSet<String>();
		fields.add(fieldname);
	}

	db.read(table,keyname,fields,new HashMap<String,ByteIterator>());
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
public void doTransactionScan(DB db)
{
	//choose a random key
	int keynum = nextKeynum();

	String startkeyname = buildKeyName(keynum);
	
	//choose a random scan length
	int len=scanlength.nextInt();

	HashSet<String> fields=null;

	if (!readallfields)
	{
		//read a random field  
		String fieldname="field"+fieldchooser.nextString();

		fields=new HashSet<String>();
		fields.add(fieldname);
	}

	db.scan(table,startkeyname,len,fields,new Vector<HashMap<String,ByteIterator>>());
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
public void doTransactionUpdate(DB db)
{
	//choose a random key
	int keynum = nextKeynum();

	String keyname=buildKeyName(keynum);

	HashMap<String,ByteIterator> values;

	if (writeallfields)
	{
	   //new data for all the fields
	   values = buildValues();
	}
	else
	{
	   //update a random field
	   values = buildUpdate();
	}

	db.update(table,keyname,values);
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
@Override
/**
 * 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. See this class's description for a discussion of error codes.
 */
public int delete(String table, String key) {
    com.mongodb.DB db=null;
    try {
        db = mongo.getDB(database);
        db.requestStart();
        DBCollection collection = db.getCollection(table);
        DBObject q = new BasicDBObject().append("_id", key);
        WriteResult res = collection.remove(q, writeConcern);
        return res.getN() == 1 ? 0 : 1;
    } catch (Exception e) {
        System.err.println(e.toString());
        return 1;
    }
    finally
    {
        if (db!=null)
        {
            db.requestDone();
        }
    }
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
@Override
  /**
   * 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. See this class's description for a discussion of error codes.
   */
  public int insert(String table, String key, HashMap<String, ByteIterator> values) {
      com.mongodb.DB db = null;
      try {
          db = mongo.getDB(database);

          db.requestStart();

          DBCollection collection = db.getCollection(table);
          DBObject r = new BasicDBObject().append("_id", key);
   for(String k: values.keySet()) {
r.put(k, values.get(k).toArray());
   }
          WriteResult res = collection.insert(r,writeConcern);
          return res.getError() == null ? 0 : 1;
      } catch (Exception e) {
          System.err.println(e.toString());
          return 1;
      } finally {
          if (db!=null)
          {
              db.requestDone();
          }
      }
  }
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
/**
 * Do one insert operation. Because it will be called concurrently from multiple client threads, this 
 * function must be thread safe. However, avoid synchronized, or the threads will block waiting for each 
 * other, and it will be difficult to reach the target throughput. Ideally, this function would have no side
 * effects other than DB operations.
 */
public boolean doInsert(DB db, Object threadstate)
{
	int keynum=keysequence.nextInt();
	String dbkey = buildKeyName(keynum);
	HashMap<String, ByteIterator> values = buildValues();
	if (db.insert(table,dbkey,values) == 0)
		return true;
	else
		return false;
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
/**
 * Do one transaction operation. Because it will be called concurrently from multiple client threads, this 
 * function must be thread safe. However, avoid synchronized, or the threads will block waiting for each 
 * other, and it will be difficult to reach the target throughput. Ideally, this function would have no side
 * effects other than DB operations.
 */
public boolean doTransaction(DB db, Object threadstate)
{
	String op=operationchooser.nextString();

	if (op.compareTo("READ")==0)
	{
		doTransactionRead(db);
	}
	else if (op.compareTo("UPDATE")==0)
	{
		doTransactionUpdate(db);
	}
	else if (op.compareTo("INSERT")==0)
	{
		doTransactionInsert(db);
	}
	else if (op.compareTo("SCAN")==0)
	{
		doTransactionScan(db);
	}
	else
	{
		doTransactionReadModifyWrite(db);
	}
	
	return true;
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
public void doTransactionInsert(DB db)
{
	//choose the next key
	int keynum=transactioninsertkeysequence.nextInt();

	String dbkey = buildKeyName(keynum);

	HashMap<String, ByteIterator> values = buildValues();
	db.insert(table,dbkey,values);
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
@Override
  /**
   * 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. See this class's description for a discussion of error codes.
   */
  public int insert(String table, String key, HashMap<String, ByteIterator> values) {
      com.mongodb.DB db = null;
      try {
          db = mongo.getDB(database);

          db.requestStart();

          DBCollection collection = db.getCollection(table);
          DBObject r = new BasicDBObject().append("_id", key);
   for(String k: values.keySet()) {
r.put(k, values.get(k).toArray());
   }
          WriteResult res = collection.insert(r,writeConcern);
          return res.getError() == null ? 0 : 1;
      } catch (Exception e) {
          e.printStackTrace();
          return 1;
      } finally {
          if (db!=null)
          {
              db.requestDone();
          }
      }
  }
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
@Override
@SuppressWarnings("unchecked")
/**
 * 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 or "not found".
 */
public int read(String table, String key, Set<String> fields,
        HashMap<String, ByteIterator> result) {
    com.mongodb.DB db = null;
    try {
        db = mongo.getDB(database);

        db.requestStart();

        DBCollection collection = db.getCollection(table);
        DBObject q = new BasicDBObject().append("_id", key);
        DBObject fieldsToReturn = new BasicDBObject();
        boolean returnAllFields = fields == null;

        DBObject queryResult = null;
        if (!returnAllFields) {
            Iterator<String> iter = fields.iterator();
            while (iter.hasNext()) {
                fieldsToReturn.put(iter.next(), 1);
            }
            queryResult = collection.findOne(q, fieldsToReturn);
        } else {
            queryResult = collection.findOne(q);
        }

        if (queryResult != null) {
            result.putAll(queryResult.toMap());
        }
        return queryResult != null ? 0 : 1;
    } catch (Exception e) {
        System.err.println(e.toString());
        return 1;
    } finally {
        if (db!=null)
        {
            db.requestDone();
        }
    }
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
@Override
/**
 * 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. See this class's description for a discussion of error codes.
 */
public int update(String table, String key, HashMap<String, ByteIterator> values) {
    com.mongodb.DB db = null;
    try {
        db = mongo.getDB(database);

        db.requestStart();

        DBCollection collection = db.getCollection(table);
        DBObject q = new BasicDBObject().append("_id", key);
        DBObject u = new BasicDBObject();
        DBObject fieldsToSet = new BasicDBObject();
        Iterator<String> keys = values.keySet().iterator();
        while (keys.hasNext()) {
            String tmpKey = keys.next();
            fieldsToSet.put(tmpKey, values.get(tmpKey).toArray());

        }
        u.put("$set", fieldsToSet);
        WriteResult res = collection.update(q, u, false, false,
                writeConcern);
        return res.getN() == 1 ? 0 : 1;
    } catch (Exception e) {
        System.err.println(e.toString());
        return 1;
    } finally {
        if (db!=null)
        {
            db.requestDone();
        }
    }
}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
@Override
@SuppressWarnings("unchecked")
/**
 * 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. See this class's description for a discussion of error codes.
 */
public int scan(String table, String startkey, int recordcount,
        Set<String> fields, Vector<HashMap<String, ByteIterator>> result) {
    com.mongodb.DB db=null;
    try {
        db = mongo.getDB(database);
        db.requestStart();
        DBCollection collection = db.getCollection(table);
        // { "_id":{"$gte":startKey, "$lte":{"appId":key+"\uFFFF"}} }
        DBObject scanRange = new BasicDBObject().append("$gte", startkey);
        DBObject q = new BasicDBObject().append("_id", scanRange);
        DBCursor cursor = collection.find(q).limit(recordcount);
        while (cursor.hasNext()) {
            //toMap() returns a Map, but result.add() expects a Map<String,String>. Hence, the suppress warnings.
            result.add(StringByteIterator.getByteIteratorMap((Map<String,String>)cursor.next().toMap()));
        }

        return 0;
    } catch (Exception e) {
        System.err.println(e.toString());
        return 1;
    }
    finally
    {
        if (db!=null)
        {
            db.requestDone();
        }
    }

}
 

import com.yahoo.ycsb.DB; //导入依赖的package包/类
public void doTransactionReadModifyWrite(DB db)
{
	//choose a random key
	int keynum = nextKeynum();

	String keyname = buildKeyName(keynum);

	HashSet<String> fields=null;

	if (!readallfields)
	{
		//read a random field  
		String fieldname="field"+fieldchooser.nextString();

		fields=new HashSet<String>();
		fields.add(fieldname);
	}
	
	HashMap<String,ByteIterator> values;

	if (writeallfields)
	{
	   //new data for all the fields
	   values = buildValues();
	}
	else
	{
	   //update a random field
	   values = buildUpdate();
	}

	//do the transaction
	
	long st=System.currentTimeMillis();

	db.read(table,keyname,fields,new HashMap<String,ByteIterator>());
	
	db.update(table,keyname,values);

	long en=System.currentTimeMillis();
	
	Measurements.getMeasurements().measure("READ-MODIFY-WRITE", (int)(en-st));
}