org.neo4j.index.internal.gbptree

Interface Writer<KEY,VALUE>

Type Parameters:

KEY - type of keys

VALUE - type of values

All Superinterfaces:

AutoCloseable, Closeable

public interface Writer<KEY,VALUE>
extends Closeable

Able to merge(Object, Object, ValueMerger) and remove(Object) key/value pairs into a GBPTree. After all modifications have taken place the writer must be closed, typically using try-with-resource clause.

Method Summary

Modifier and Type	Method and Description
void	merge(KEY key, VALUE value, ValueMerger<VALUE> valueMerger) If the key doesn't already exist in the index the key will be added and the value associated with it.
void	put(KEY key, VALUE value) Associate given key with given value.
VALUE	remove(KEY key) Removes a key, returning it's associated value, if found.

Methods inherited from interface java.io.Closeable

close

Method Detail

put

void put(KEY key,
         VALUE value)
  throws IOException

Associate given key with given value. Any existing value associated with key will be overwritten.

Parameters:

key - key to associate with value

value - value to associate with key

Throws:

IOException - on index access error.

merge

void merge(KEY key,
           VALUE value,
           ValueMerger<VALUE> valueMerger)
    throws IOException

If the key doesn't already exist in the index the key will be added and the value associated with it. If the key already exists then its existing value will be merged with the given value, using the ValueMerger. If the ValueMerger returns a non-null value that value will be associated with the key, otherwise (if it returns null) nothing will be written.

Parameters:

key - key for which to merge values.

value - value to merge with currently associated value for the key.

valueMerger - ValueMerger to consult if key already exists.

Throws:

IOException - on index access error.

remove

VALUE remove(KEY key)
      throws IOException

Removes a key, returning it's associated value, if found.

Parameters:

key - key to remove.

Returns:

value which was associated with the remove key, if found, otherwise null.

Throws:

IOException - on index access error.