jetbrains.exodus.io

Class DataReaderWriterProvider

java.lang.Object

jetbrains.exodus.io.DataReaderWriterProvider

public abstract class DataReaderWriterProvider
extends java.lang.Object

Service provider interface for creation instances of DataReader and DataWriter. DataReader and DataWriter are used by Log implementation to perform basic operations with blocks (.xd files) and basic read/write/delete operations. Service provider interface is identified by a fully-qualified name of its implementation. When opening an Environment, DEFAULT_READER_WRITER_PROVIDER is used as default provide name. To use a custom I/O provider, specify its fully-qualified name as a parameter of EnvironmentConfig.setLogDataReaderWriterProvider(java.lang.String). On Environment creation new instance of DataReaderWriterProvider is created.

Since:

1.3.0

See Also:

Block, DataReader, DataWriter, EnvironmentConfig.getLogDataReaderWriterProvider(), EnvironmentConfig.setLogDataReaderWriterProvider(java.lang.String)

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	DEFAULT_READER_WRITER_PROVIDER Fully-qualified name of default DataReaderWriteProvider}.

Constructor Summary

Constructors

Constructor and Description
DataReaderWriterProvider()

Method Summary

Modifier and Type	Method and Description
static @Nullable DataReaderWriterProvider	getProvider(@NotNull java.lang.String providerName) Gets a DataReaderWriterProvider implementation by specified provider name.
boolean	isInMemory() Returns true if the DataReaderWriterProvider creates in-memory DataReader and DataWriter.
boolean	isReadonly() Returns true if the DataReaderWriterProvider creates read-only DataWriter.
abstract jetbrains.exodus.core.dataStructures.Pair<DataReader,DataWriter>	newReaderWriter(@NotNull java.lang.String location) Creates pair of new instances of DataReader and DataWriter by specified location.
void	onEnvironmentCreated(@NotNull Environment environment) Callback method which is called when an environment is been opened/created.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_READER_WRITER_PROVIDER

public static final java.lang.String DEFAULT_READER_WRITER_PROVIDER

Fully-qualified name of default DataReaderWriteProvider}.

See Also:

Constant Field Values

Constructor Detail

DataReaderWriterProvider

public DataReaderWriterProvider()

Method Detail

newReaderWriter

public abstract jetbrains.exodus.core.dataStructures.Pair<DataReader,DataWriter> newReaderWriter(@NotNull
                                                                                                 @NotNull java.lang.String location)

Creates pair of new instances of DataReader and DataWriter by specified location. What is location depends on the implementation of DataReaderWriterProvider, e.g. for FileDataReaderWriterProvider location is a full path on local file system where the database is located.

Parameters:

location - identifies the database in this DataReaderWriterProvider

Returns:

pair of new instances of DataReader and DataWriter

isInMemory

public boolean isInMemory()

Returns true if the DataReaderWriterProvider creates in-memory DataReader and DataWriter.

Returns:

true if the DataReaderWriterProvider creates in-memory DataReader and DataWriter

isReadonly

public boolean isReadonly()

Returns true if the DataReaderWriterProvider creates read-only DataWriter.

Returns:

true if the DataReaderWriterProvider creates read-only DataWriter

onEnvironmentCreated

public void onEnvironmentCreated(@NotNull
                                 @NotNull Environment environment)

Callback method which is called when an environment is been opened/created. Can be used in implementation of the DataReaderWriterProvider to access directly an Environment instance, its config, etc. Creation of environment is not completed when the method is called.

Parameters:

environment - Environment instance which is been opened/created using this DataReaderWriterProvider

getProvider

@Nullable
public static @Nullable DataReaderWriterProvider getProvider(@NotNull
                                                                        @NotNull java.lang.String providerName)

Gets a DataReaderWriterProvider implementation by specified provider name.

Parameters:

providerName - fully-qualified name of DataReaderWriterProvider implementation

Returns:

DataReaderWriterProvider implementation or null if the service could not be loaded