org.komamitsu.wormhole4j

Class Wormhole<T>

java.lang.Object

org.komamitsu.wormhole4j.Wormhole<T>

Type Parameters:

T - the type of values stored in this index

public class Wormhole<T>
extends java.lang.Object

Wormhole is an in-memory ordered index for key-value pairs.

This implementation supports fast lookups, inserts, deletes, and range scans. Keys are String only.

Field Summary

Fields

Modifier and Type	Field and Description
static char	BITMAP_ID_OF_SMALLEST_TOKEN
static java.lang.String	SMALLEST_TOKEN

Constructor Summary

Constructors

Constructor and Description
Wormhole() Creates a Wormhole with the default leaf node size.
Wormhole(int leafNodeSize) Creates a Wormhole with the specified leaf node size.
Wormhole(int leafNodeSize, boolean debugMode) Creates a Wormhole with the specified leaf node size and optional debug mode.

Method Summary

Modifier and Type	Method and Description
boolean	delete(java.lang.String key) Deletes a key-value pair if present.
T	get(java.lang.String key) Retrieves the value associated with the specified key.
void	put(java.lang.String key, T value) Inserts or updates a key-value pair.
void	scan(java.lang.String startKey, java.lang.String endKey, boolean isEndKeyExclusive, java.util.function.Function<KeyValue<T>,java.lang.Boolean> function) Scans a range of keys and applies a function to each result.
java.util.List<KeyValue<T>>	scanWithCount(java.lang.String startKey, int count) Scans the index starting from a key and collects up to count pairs.
void	scanWithExclusiveEndKey(java.lang.String startKey, java.lang.String endKey, java.util.function.Function<KeyValue<T>,java.lang.Boolean> function) Scans a range of keys where the end key is exclusive.
void	scanWithInclusiveEndKey(java.lang.String startKey, java.lang.String endKey, java.util.function.Function<KeyValue<T>,java.lang.Boolean> function) Scans a range of keys where the end key is inclusive.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

SMALLEST_TOKEN

public static final java.lang.String SMALLEST_TOKEN

See Also:

Constant Field Values

BITMAP_ID_OF_SMALLEST_TOKEN

public static final char BITMAP_ID_OF_SMALLEST_TOKEN

See Also:

Constant Field Values

Constructor Detail

Wormhole

public Wormhole()

Creates a Wormhole with the default leaf node size.

Wormhole

public Wormhole(int leafNodeSize)

Creates a Wormhole with the specified leaf node size.

Parameters:

leafNodeSize - maximum number of entries in a leaf node

Wormhole

public Wormhole(int leafNodeSize,
                boolean debugMode)

Creates a Wormhole with the specified leaf node size and optional debug mode.

Parameters:

leafNodeSize - maximum number of entries in a leaf node

debugMode - enables internal consistency checks if true

Method Detail

put

public void put(java.lang.String key,
                T value)

Inserts or updates a key-value pair.

Parameters:

key - the key (must not be null)

value - the value to associate with the key

delete

public boolean delete(java.lang.String key)

Deletes a key-value pair if present.

Parameters:

key - the key to remove

Returns:

true if the key was removed, false otherwise

get

@Nullable
public T get(java.lang.String key)

Retrieves the value associated with the specified key.

Parameters:

key - the key to search for

Returns:

the value, or null if not found

scanWithCount

public java.util.List<KeyValue<T>> scanWithCount(java.lang.String startKey,
                                                 int count)

Scans the index starting from a key and collects up to count pairs.

Parameters:

startKey - the starting key (inclusive)

count - maximum number of results to return

Returns:

a list of key-value pairs

scan

public void scan(@Nullable
                 java.lang.String startKey,
                 @Nullable
                 java.lang.String endKey,
                 boolean isEndKeyExclusive,
                 java.util.function.Function<KeyValue<T>,java.lang.Boolean> function)

Scans a range of keys and applies a function to each result.

Parameters:

startKey - the start key (inclusive) or null for the first key

endKey - the end key (exclusive or inclusive based on isEndKeyExclusive)

isEndKeyExclusive - whether endKey is exclusive

function - a function applied to each key-value pair; return false to stop scanning

scanWithExclusiveEndKey

public void scanWithExclusiveEndKey(@Nullable
                                    java.lang.String startKey,
                                    @Nullable
                                    java.lang.String endKey,
                                    java.util.function.Function<KeyValue<T>,java.lang.Boolean> function)

Scans a range of keys where the end key is exclusive.

Parameters:

startKey - the start key (inclusive) or null for the first key

endKey - the end key (exclusive)

function - a function applied to each key-value pair; return false to stop scanning

scanWithInclusiveEndKey

public void scanWithInclusiveEndKey(@Nullable
                                    java.lang.String startKey,
                                    @Nullable
                                    java.lang.String endKey,
                                    java.util.function.Function<KeyValue<T>,java.lang.Boolean> function)

Scans a range of keys where the end key is inclusive.

Parameters:

startKey - the start key (inclusive) or null for the first key

endKey - the end key (inclusive)

function - a function applied to each key-value pair; return false to stop scanning

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object