TrieReader (51Degrees.detection.core API)

java.lang.Object
- fiftyone.mobile.detection.readers.TrieReader

```
public class TrieReader
extends Object
```
Due to the size of the Trie tree structure, the data cannot fit into a single ByteBuffer. Therefore, this class is used to wrap the file channel and and become logically one channel.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

private static class TrieReader.DataType
Defines what data type is being read from a given buffer.

Nested Classes
Modifier and Type	Class and Description
`private static class`	`TrieReader.DataType` Defines what data type is being read from a given buffer.

Field Summary

Fields
Modifier and Type	Field and Description
`private int`	`_bufferIndex` The index of the buffer that _position is pointed at.
`private ArrayList<MappedByteBuffer>`	`_buffers` Buffers mapped to the files channel.
`private long`	`_globalPosition`
`private long`	`_position` Logical position of the data needed in the file.
`private long`	`_start` The start position of the tree in the trie file.
`private FileChannel`	`_triFile` The File Channel linked to the trie data.

Constructor Summary

Constructors
Constructor and Description

TrieReader(FileChannel reader)
Creates the class by creating multiple ByteBuffers that can be read from.

Constructors
Constructor and Description
`TrieReader(FileChannel reader)` Creates the class by creating multiple ByteBuffers that can be read from.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Clears the ByteBuffers and closes the File Channel.
`private byte`	`getNextByte()` Gets the MappedByteBuffer for that this class is currently positioned on, automatically incrementing position and changing buffer if required.
`long`	`getPos()` Returns the current logical position value.
`private byte[]`	`getValue(TrieReader.DataType dataType)` Reads a certain data type from the file e.g.
`byte`	`readByte()`
`byte[]`	`readBytes(int length)`
`int`	`readInt()` Read an signed integer from the file at the current location.
`long`	`readLong()` Read an signed long from the file at the current location.
`long`	`readLong(long position)` Read an signed long from the file at a specified location.
`short`	`readUByte()` Read an Unsigned byte from the file at the current location.
`short`	`readUByte(long position)` Read an Unsigned byte from the file at a specified location.
`long`	`readUInt()` Read an Unsigned integer from the file at the current location.
`int`	`readUShort()` Read an Unsigned short from the file at the current location.
`int`	`readUShort(long position)` Read an Unsigned short from the file at a specified location.
`void`	`setPos(long position)` Sets the logical position in the file.

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

- Field Detail
  - _buffers
```
private ArrayList<MappedByteBuffer> _buffers
```
    Buffers mapped to the files channel.
  - _triFile
```
private final FileChannel _triFile
```
    The File Channel linked to the trie data.
  - _start
```
private final long _start
```
    The start position of the tree in the trie file.
  - _position
```
private long _position
```
    Logical position of the data needed in the file.
  - _bufferIndex
```
private int _bufferIndex
```
    The index of the buffer that _position is pointed at.
  - _globalPosition
```
private long _globalPosition
```
- Constructor Detail
  - TrieReader
```
public TrieReader(FileChannel reader)
           throws IOException
```
    Creates the class by creating multiple ByteBuffers that can be read from.
    
    Parameters:
    
    reader - File channel to read from.
    
    Throws:
    
    IOException
- Method Detail
  - getPos
```
public long getPos()
```
    Returns the current logical position value.
    
    Returns:
    
    the current logical position in the file.
  - setPos
```
public void setPos(long position)
```
    Sets the logical position in the file.
    
    Parameters:
    
    position - position value.
  - readUByte
```
public short readUByte()
```
    Read an Unsigned byte from the file at the current location.
    
    Returns:
    
    The value read.
  - readUByte
```
public short readUByte(long position)
```
    Read an Unsigned byte from the file at a specified location.
    
    Parameters:
    
    position - Position to read from.
    
    Returns:
    
    The value read.
  - readUShort
```
public int readUShort()
```
    Read an Unsigned short from the file at the current location.
    
    Returns:
    
    The value read.
  - readUShort
```
public int readUShort(long position)
```
    Read an Unsigned short from the file at a specified location.
    
    Parameters:
    
    position - Position to read from.
    
    Returns:
    
    The value read.
  - readUInt
```
public long readUInt()
              throws IOException
```
    Read an Unsigned integer from the file at the current location.
    
    Returns:
    
    The Value read.
    
    Throws:
    
    IOException
  - readInt
```
public int readInt()
            throws IOException
```
    Read an signed integer from the file at the current location.
    
    Returns:
    
    The Value read.
    
    Throws:
    
    IOException
  - readLong
```
public long readLong()
```
    Read an signed long from the file at the current location.
    
    Returns:
    
    The Value read.
    
    Throws:
    
    IOException
  - readLong
```
public long readLong(long position)
              throws IOException
```
    Read an signed long from the file at a specified location.
    
    Parameters:
    
    position - Position to read from.
    
    Returns:
    
    The value read.
    
    Throws:
    
    IOException
  - getNextByte
```
private byte getNextByte()
```
    Gets the MappedByteBuffer for that this class is currently positioned on, automatically incrementing position and changing buffer if required.
  - readByte
```
public byte readByte()
```
  - readBytes
```
public byte[] readBytes(int length)
```
  - getValue
```
private byte[] getValue(TrieReader.DataType dataType)
```
    Reads a certain data type from the file e.g. byte, Unsigned Integer etc.
    
    Parameters:
    
    dataType - Type of data to read.
    
    Returns:
    
    byte array of data.
  - close
```
public void close()
           throws IOException
```
    Clears the ByteBuffers and closes the File Channel.
    
    Throws:
    
    IOException

Class TrieReader

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

_buffers

_triFile

_start

_position

_bufferIndex

_globalPosition

Constructor Detail

TrieReader

Method Detail

getPos

setPos

readUByte

readUByte

readUShort

readUShort

readUInt

readInt

readLong

readLong

getNextByte

readByte

readBytes

getValue

close