Package it.unimi.dsi.sux4j.mph

Class GOVMinimalPerfectHashFunction.Builder<T>

java.lang.Object

it.unimi.dsi.sux4j.mph.GOVMinimalPerfectHashFunction.Builder<T>

Enclosing class:

GOVMinimalPerfectHashFunction<T>

public static class GOVMinimalPerfectHashFunction.Builder<T>
extends Object

A builder class for GOVMinimalPerfectHashFunction.

Field Summary

Fields

Modifier and Type	Field	Description
protected BucketedHashStore<T>	bucketedHashStore
protected boolean	built	Whether build() has already been called.
protected Iterable<? extends T>	keys
protected int	signatureWidth
protected File	tempDir
protected TransformationStrategy<? super T>	transform

Constructor Summary

Constructors

Constructor	Description
Builder()

Method Summary

Modifier and Type	Method	Description
GOVMinimalPerfectHashFunction<T>	build()	Builds a minimal perfect hash function.
GOVMinimalPerfectHashFunction.Builder<T>	keys(Iterable<? extends T> keys)	Specifies the keys to hash; if you have specified a BucketedHashStore, it can be null.
GOVMinimalPerfectHashFunction.Builder<T>	signed(int signatureWidth)	Specifies that the resulting GOVMinimalPerfectHashFunction should be signed using a given number of bits per key.
GOVMinimalPerfectHashFunction.Builder<T>	store(BucketedHashStore<T> bucketedHashStore)	Specifies a bucketed hash store containing the keys.
GOVMinimalPerfectHashFunction.Builder<T>	tempDir(File tempDir)	Specifies a temporary directory for the BucketedHashStore.
GOVMinimalPerfectHashFunction.Builder<T>	transform(TransformationStrategy<? super T> transform)	Specifies the transformation strategy for the keys to hash.

Methods inherited from class java.lang.Object

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

Field Details

keys

protected Iterable<? extends T> keys

transform

protected TransformationStrategy<? super T> transform

signatureWidth

protected int signatureWidth

tempDir

protected File tempDir

bucketedHashStore

protected BucketedHashStore<T> bucketedHashStore

built

protected boolean built

Whether build() has already been called.

Constructor Details

Builder

public Builder()

Method Details

keys

public GOVMinimalPerfectHashFunction.Builder<T> keys(Iterable<? extends T> keys)

Specifies the keys to hash; if you have specified a BucketedHashStore, it can be null.

Parameters:

keys - the keys to hash.

Returns:

this builder.

transform

public GOVMinimalPerfectHashFunction.Builder<T> transform(TransformationStrategy<? super T> transform)

Specifies the transformation strategy for the keys to hash.

Parameters:

transform - a transformation strategy for the keys to hash.

Returns:

this builder.

signed

public GOVMinimalPerfectHashFunction.Builder<T> signed(int signatureWidth)

Specifies that the resulting GOVMinimalPerfectHashFunction should be signed using a given number of bits per key.

Parameters:

signatureWidth - a signature width, or 0 for no signature.

Returns:

this builder.

tempDir

public GOVMinimalPerfectHashFunction.Builder<T> tempDir(File tempDir)

Specifies a temporary directory for the BucketedHashStore.

Parameters:

tempDir - a temporary directory for the BucketedHashStore files, or null for the standard temporary directory.

Returns:

this builder.

store

public GOVMinimalPerfectHashFunction.Builder<T> store(BucketedHashStore<T> bucketedHashStore)

Specifies a bucketed hash store containing the keys.

Parameters:

bucketedHashStore - a bucketed hash store containing the keys, or null; the store can be unchecked, but in this case you must specify keys and a transform (otherwise, in case of a hash collision in the store an IllegalStateException will be thrown).

Returns:

this builder.

build

public GOVMinimalPerfectHashFunction<T> build()
                                       throws IOException

Builds a minimal perfect hash function.

Returns:

a GOVMinimalPerfectHashFunction instance with the specified parameters.

Throws:

IllegalStateException - if called more than once.

IOException