Env (LmdbJava 0.6.1 API)

java.lang.Object
- org.lmdbjava.Env<T>

Type Parameters:

T - buffer type

All Implemented Interfaces:

java.lang.AutoCloseable
```
public final class Env<T>
extends java.lang.Object
implements java.lang.AutoCloseable
```
LMDB environment.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`Env.AlreadyClosedException` Object has already been closed and the operation is therefore prohibited.
`static class`	`Env.AlreadyOpenException` Object has already been opened and the operation is therefore prohibited.
`static class`	`Env.Builder<T>` Builder for configuring and opening Env.
`static class`	`Env.FileInvalidException` File is not a valid LMDB file.
`static class`	`Env.InvalidCopyDestination` The specified copy destination is invalid.
`static class`	`Env.MapFullException` Environment mapsize reached.
`static class`	`Env.ReadersFullException` Environment maxreaders reached.
`static class`	`Env.VersionMismatchException` Environment version mismatch.

Field Summary

Fields
Modifier and Type	Field and Description
`static java.lang.String`	`DISABLE_CHECKS_PROP` Java system property name that can be set to disable optional checks.
`static boolean`	`SHOULD_CHECK` Indicates whether optional checks should be applied in LmdbJava.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`close()` Close the handle.
`void`	`copy(java.io.File path, CopyFlags... flags)` Copies an LMDB environment to the specified destination path.
`static Env.Builder<java.nio.ByteBuffer>`	`create()` Create an `Env` using the `ByteBufferProxy.PROXY_OPTIMAL`.
`static <T> Env.Builder<T>`	`create(BufferProxy<T> proxy)` Create an `Env` using the passed `BufferProxy`.
`java.util.List<byte[]>`	`getDbiNames()` Obtain the DBI names.
`int`	`getMaxKeySize()` Get the maximum size of keys and MDB_DUPSORT data we can write.
`EnvInfo`	`info()` Return information about this environment.
`boolean`	`isClosed()` Indicates whether this environment has been closed.
`boolean`	`isReadOnly()` Indicates if this environment was opened with `EnvFlags.MDB_RDONLY_ENV`.
`static Env<java.nio.ByteBuffer>`	`open(java.io.File path, int size, EnvFlags... flags)` Opens an environment with a single default database in 0664 mode using the `ByteBufferProxy.PROXY_OPTIMAL`.
`Dbi<T>`	`openDbi(byte[] name, java.util.Comparator<T> comparator, DbiFlags... flags)` Open the `Dbi`.
`Dbi<T>`	`openDbi(byte[] name, DbiFlags... flags)` Open the `Dbi`.
`Dbi<T>`	`openDbi(java.lang.String name, java.util.Comparator<T> comparator, DbiFlags... flags)` Convenience method that opens a `Dbi` with a UTF-8 database name and custom comparator.
`Dbi<T>`	`openDbi(java.lang.String name, DbiFlags... flags)` Convenience method that opens a `Dbi` with a UTF-8 database name.
`Stat`	`stat()` Return statistics about this environment.
`void`	`sync(boolean force)` Flushes the data buffers to disk.
`Txn<T>`	`txn(Txn<T> parent, TxnFlags... flags)` Obtain a transaction with the requested parent and flags.
`Txn<T>`	`txnRead()` Obtain a read-only transaction.
`Txn<T>`	`txnWrite()` Obtain a read-write transaction.

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

- Field Detail
  - DISABLE_CHECKS_PROP
```
public static final java.lang.String DISABLE_CHECKS_PROP
```
    Java system property name that can be set to disable optional checks.
    
    See Also:
    
    Constant Field Values
  - SHOULD_CHECK
```
public static final boolean SHOULD_CHECK
```
    Indicates whether optional checks should be applied in LmdbJava. Optional checks are only disabled in critical paths (see package-level JavaDocs). Non-critical paths have optional checks performed at all times, regardless of this property.
- Method Detail
  - create
```
public static Env.Builder<java.nio.ByteBuffer> create()
```
    Create an Env using the ByteBufferProxy.PROXY_OPTIMAL.
    
    Returns:
    
    the environment (never null)
  - create
```
public static <T> Env.Builder<T> create(BufferProxy<T> proxy)
```
    Create an Env using the passed BufferProxy.
    
    Type Parameters:
    
    T - buffer type
    
    Parameters:
    
    proxy - the proxy to use (required)
    
    Returns:
    
    the environment (never null)
  - open
```
public static Env<java.nio.ByteBuffer> open(java.io.File path,
                                            int size,
                                            EnvFlags... flags)
```
    Opens an environment with a single default database in 0664 mode using the ByteBufferProxy.PROXY_OPTIMAL.
    
    Parameters:
    
    path - file system destination
    
    size - size in megabytes
    
    flags - the flags for this new environment
    
    Returns:
    
    env the environment (never null)
  - close
```
public void close()
```
    Close the handle.
    Will silently return if already closed or never opened.
    
    Specified by:
    
    close in interface java.lang.AutoCloseable
  - copy
```
public void copy(java.io.File path,
                 CopyFlags... flags)
```
    Copies an LMDB environment to the specified destination path.
    This function may be used to make a backup of an existing environment. No lockfile is created, since it gets recreated at need.
    Note: This call can trigger significant file size growth if run in parallel with write transactions, because it employs a read-only transaction. See long-lived transactions under "Caveats" in the LMDB native documentation.
    
    Parameters:
    
    path - destination directory, which must exist, be writable and empty
    
    flags - special options for this copy
  - getDbiNames
```
public java.util.List<byte[]> getDbiNames()
```
    Obtain the DBI names.
    This method is only compatible with Envs that use named databases. If an unnamed Dbi is being used to store data, this method will attempt to return all such keys from the unnamed database.
    
    Returns:
    
    a list of DBI names (never null)
  - getMaxKeySize
```
public int getMaxKeySize()
```
    Get the maximum size of keys and MDB_DUPSORT data we can write.
    
    Returns:
    
    the maximum size of keys.
  - info
```
public EnvInfo info()
```
    Return information about this environment.
    
    Returns:
    
    an immutable information object.
  - isClosed
```
public boolean isClosed()
```
    Indicates whether this environment has been closed.
    
    Returns:
    
    true if closed
  - isReadOnly
```
public boolean isReadOnly()
```
    Indicates if this environment was opened with EnvFlags.MDB_RDONLY_ENV.
    
    Returns:
    
    true if read-only
  - openDbi
```
public Dbi<T> openDbi(java.lang.String name,
                      DbiFlags... flags)
```
    Convenience method that opens a Dbi with a UTF-8 database name.
    
    Parameters:
    
    name - name of the database (or null if no name is required)
    
    flags - to open the database with
    
    Returns:
    
    a database that is ready to use
  - openDbi
```
public Dbi<T> openDbi(java.lang.String name,
                      java.util.Comparator<T> comparator,
                      DbiFlags... flags)
```
    Convenience method that opens a Dbi with a UTF-8 database name and custom comparator.
    
    Parameters:
    
    name - name of the database (or null if no name is required)
    
    comparator - custom comparator callback (or null to use LMDB default)
    
    flags - to open the database with
    
    Returns:
    
    a database that is ready to use
  - openDbi
```
public Dbi<T> openDbi(byte[] name,
                      DbiFlags... flags)
```
    Open the Dbi.
    
    Parameters:
    
    name - name of the database (or null if no name is required)
    
    flags - to open the database with
    
    Returns:
    
    a database that is ready to use
  - openDbi
```
public Dbi<T> openDbi(byte[] name,
                      java.util.Comparator<T> comparator,
                      DbiFlags... flags)
```
    Open the Dbi.
    If a custom comparator is specified, this comparator is called from LMDB any time it needs to compare two keys. The comparator must be used any time any time this database is opened, otherwise database corruption may occur. The custom comparator will also be used whenever a CursorIterator is created from the returned Dbi. If a custom comparator is not specified, LMDB's native default lexicographical order is used. The default comparator is typically more efficient (as there is no need for the native library to call back into Java for the comparator result).
    
    Parameters:
    
    name - name of the database (or null if no name is required)
    
    comparator - custom comparator callback (or null to use LMDB default)
    
    flags - to open the database with
    
    Returns:
    
    a database that is ready to use
  - stat
```
public Stat stat()
```
    Return statistics about this environment.
    
    Returns:
    
    an immutable statistics object.
  - sync
```
public void sync(boolean force)
```
    Flushes the data buffers to disk.
    
    Parameters:
    
    force - force a synchronous flush (otherwise if the environment has the MDB_NOSYNC flag set the flushes will be omitted, and with MDB_MAPASYNC they will be asynchronous)
  - txn
```
public Txn<T> txn(Txn<T> parent,
                  TxnFlags... flags)
```
    Obtain a transaction with the requested parent and flags.
    
    Parameters:
    
    parent - parent transaction (may be null if no parent)
    
    flags - applicable flags (eg for a reusable, read-only transaction)
    
    Returns:
    
    a transaction (never null)
  - txnRead
```
public Txn<T> txnRead()
```
    Obtain a read-only transaction.
    
    Returns:
    
    a read-only transaction
  - txnWrite
```
public Txn<T> txnWrite()
```
    Obtain a read-write transaction.
    
    Returns:
    
    a read-write transaction

Class Env<T>

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DISABLE_CHECKS_PROP

SHOULD_CHECK

Method Detail

create

create

open

close

copy

getDbiNames

getMaxKeySize

info

isClosed

isReadOnly

openDbi

openDbi

openDbi

openDbi

stat

sync

txn

txnRead

txnWrite