DBFileWriter (NanoDB SQL Relational Database 0.1-SNAPSHOT API)

java.lang.Object
- edu.caltech.nanodb.storage.DBFileReader
- - edu.caltech.nanodb.storage.DBFileWriter

All Implemented Interfaces:

java.lang.AutoCloseable
```
public class DBFileWriter
extends DBFileReader
```
A subclass of DBFileReader, this class provides the basic ability to read and write a DBFile as a single sequential file, obscuring the fact that it is actually broken into pages. As the file-pointer moves through the file, the Storage Manager is used to load individual pages into the buffer manager.

It is certainly possible that a value being read or written might span two adjacent data pages. In these cases, the access will be a little slower, as the operation must access partial data from the first page, and then access the remainder of the data from the next page.

Design Note:

This class always has the current DBPage pinned, and it will unpin the current page when it moves into the next page. This means that when the writer is closed, it may still have a page that is pinned. Therefore, the class implements AutoCloseable so that users can call DBFileReader.close() on a writer to unpin the last page, or they can use this type with the "try-with-resources" Java syntax.

Field Summary

Fields
Modifier and Type Field Description

private static org.apache.logging.log4j.Logger logger
A logging object for reporting anything interesting that happens.
- Fields inherited from class edu.caltech.nanodb.storage.DBFileReader
  dbFile, dbPage, extendFile, pageSize, position, storageManager, tmpBuf

Constructor Summary

Constructors
Constructor Description

DBFileWriter(DBFile dbFile, StorageManager storageManager)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`write(byte[] b)`
`void`	`write(byte[] b, int off, int len)`
`void`	`writeBoolean(boolean v)`
`void`	`writeByte(int v)`
`void`	`writeChar(int v)`
`void`	`writeDouble(double v)`
`void`	`writeFloat(float v)`
`void`	`writeInt(int v)`
`void`	`writeLong(long v)`
`void`	`writeShort(int v)`
`void`	`writeVarString255(java.lang.String value)`
`void`	`writeVarString65535(java.lang.String value)`

Methods inherited from class edu.caltech.nanodb.storage.DBFileReader
checkDBPage, close, getDBFile, getPosition, getPositionPageNo, getPositionPageOffset, movePosition, read, read, readBoolean, readByte, readChar, readDouble, readFloat, readInt, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readVarString255, readVarString65535, setPosition

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail
- logger
```
private static org.apache.logging.log4j.Logger logger
```
  A logging object for reporting anything interesting that happens.

Constructor Detail

DBFileWriter

public DBFileWriter(DBFile dbFile,
                    StorageManager storageManager)

Method Detail

write

public void write(byte[] b,
                  int off,
                  int len)

write
```
public void write(byte[] b)
```

writeBoolean

public void writeBoolean(boolean v)

writeByte
```
public void writeByte(int v)
```

writeShort
```
public void writeShort(int v)
```

writeChar
```
public void writeChar(int v)
```

writeInt
```
public void writeInt(int v)
```

writeLong
```
public void writeLong(long v)
```

writeFloat
```
public void writeFloat(float v)
```

writeDouble
```
public void writeDouble(double v)
```

writeVarString255

public void writeVarString255(java.lang.String value)

writeVarString65535

public void writeVarString65535(java.lang.String value)