com.graphhopper.storage

Interface DataAccess

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

AbstractDataAccess, MMapDataAccess, RAMDataAccess

public interface DataAccess
extends Closeable

Life cycle: (1) object creation, (2) configuration (e.g. segment size), (3) create or loadExisting, (4) usage and calling ensureCapacity if necessary, (5) close

Author:

Peter Karich

Method Summary

Modifier and Type	Method and Description
void	close() This method makes sure that the underlying used resources are released.
DataAccess	create(long bytes) The first time you use a DataAccess object after configuring it you need to call this method.
boolean	ensureCapacity(long bytes) Ensures that the capacity of this object is at least the specified bytes.
void	flush() This method makes sure that the underlying data is written to the storage.
byte	getByte(long currentPointer)
void	getBytes(long bytePos, byte[] values, int length) Get bytes from position 'index'
long	getCapacity()
int	getHeader(int bytePos) Get 4 bytes from the header at 'index'
int	getInt(long bytePos) Get 4 bytes from position 'bytePos'
String	getName() The logical identification of this object.
int	getSegments()
int	getSegmentSize()
short	getShort(long bytePos) Get 2 bytes from position 'index'
DAType	getType()
boolean	isClosed()
boolean	loadExisting()
void	setByte(long currentPointer, byte value)
void	setBytes(long bytePos, byte[] values, int length) Set bytes from position 'index' to the specified values
void	setHeader(int bytePos, int value) Set 4 bytes at the header space index to the specified value
void	setInt(long bytePos, int value) Set 4 bytes at position 'bytePos' to the specified value
void	setShort(long bytePos, short value) Set 2 bytes at position 'index' to the specified value

Method Detail

getName

String getName()

The logical identification of this object.

setInt

void setInt(long bytePos,
            int value)

Set 4 bytes at position 'bytePos' to the specified value

getInt

int getInt(long bytePos)

Get 4 bytes from position 'bytePos'

setShort

void setShort(long bytePos,
              short value)

Set 2 bytes at position 'index' to the specified value

getShort

short getShort(long bytePos)

Get 2 bytes from position 'index'

setBytes

void setBytes(long bytePos,
              byte[] values,
              int length)

Set bytes from position 'index' to the specified values

getBytes

void getBytes(long bytePos,
              byte[] values,
              int length)

Get bytes from position 'index'

Parameters:

values - acts as output

setByte

void setByte(long currentPointer,
             byte value)

getByte

byte getByte(long currentPointer)

setHeader

void setHeader(int bytePos,
               int value)

Set 4 bytes at the header space index to the specified value

getHeader

int getHeader(int bytePos)

Get 4 bytes from the header at 'index'

create

DataAccess create(long bytes)

The first time you use a DataAccess object after configuring it you need to call this method. After that first call you have to use ensureCapacity to ensure that enough space is reserved.

flush

void flush()

This method makes sure that the underlying data is written to the storage. Keep in mind that a disc normally has an IO cache so that flush() is (less) probably not save against power loses.

close

void close()

This method makes sure that the underlying used resources are released. WARNING: it does NOT flush on close!

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

isClosed

boolean isClosed()

loadExisting

boolean loadExisting()

Returns:

true if successfully loaded from persistent storage.

getCapacity

long getCapacity()

Returns:

the allocated storage size in bytes

ensureCapacity

boolean ensureCapacity(long bytes)

Ensures that the capacity of this object is at least the specified bytes. The first time you have to call 'create' instead.

Returns:

true if size was increased

See Also:

create(long)

getSegmentSize

int getSegmentSize()

Returns:

the size of one segment in bytes

getSegments

int getSegments()

Returns:

the number of segments.

getType

DAType getType()

Returns:

the data access type of this object.