de.lmu.ifi.dbs.elki.utilities

Class ELKIBuilder<T>

java.lang.Object

de.lmu.ifi.dbs.elki.utilities.ELKIBuilder<T>

Type Parameters:

T - Class to build.

public final class ELKIBuilder<T>
extends java.lang.Object

Builder utility class. This class delegates to ListParameterization and ClassGenericsUtil, but may be easier to use in many cases. You will often need to specify the type T, because of nested generics. This is because of the way generics are implemented in Java, and we cannot easily resolve this; you have to give the type explicitly. Example: RStarTreeFactory<DoubleVector> indexfactory = new ELKIBuilder<RStarTreeFactory<DoubleVector>>(RStarTreeFactory.class) .with(AbstractPageFileFactory.Parameterizer.PAGE_SIZE_ID, 512) .with(RStarTreeFactory.Parameterizer.BULK_SPLIT_ID, SortTileRecursiveBulkSplit.class) .build(); with new ELKIBuilder<RStarTreeFactory<DoubleVector>> this code is fine, whereas new ELKIBuilder<> will cause an unchecked cast warning, because you are, in fact, casting a RStarTreeFactory (without generics) into a RStarTreeFactory<DoubleVector> here.

Since:

0.7.5

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.Class<? super T>	clazz Class to build.
private static Logging	LOG Class logger.
private ListParameterization	p Parameter list.

Constructor Summary

Constructors

Constructor and Description
ELKIBuilder(java.lang.Class<? super T> clazz) Constructor.

Method Summary

Modifier and Type	Method and Description
<C extends T> C	build() Instantiate, consuming the parameter list.
ELKIBuilder<T>	with(OptionID opt) Add a flag to the builder.
ELKIBuilder<T>	with(OptionID opt, java.lang.Object value) Add an option to the builder.
ELKIBuilder<T>	with(java.lang.String opt) Add a flag to the builder.
ELKIBuilder<T>	with(java.lang.String opt, java.lang.Object value) Add an option to the builder.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final Logging LOG

Class logger.

clazz

private java.lang.Class<? super T> clazz

Class to build.

p

private ListParameterization p

Parameter list.

Constructor Detail

ELKIBuilder

public ELKIBuilder(java.lang.Class<? super T> clazz)

Constructor. You will often need to specify the type T, because of nested generics. This is because of the way generics are implemented in Java, and we cannot easily resolve this; you have to give the type explicitly. Example: RStarTreeFactory<DoubleVector> indexfactory = new ELKIBuilder<RStarTreeFactory<DoubleVector>>(RStarTreeFactory.class) .with(AbstractPageFileFactory.Parameterizer.PAGE_SIZE_ID, 512) .with(RStarTreeFactory.Parameterizer.BULK_SPLIT_ID, SortTileRecursiveBulkSplit.class) .build(); with new ELKIBuilder<RStarTreeFactory<DoubleVector>> this code is fine, whereas new ELKIBuilder<> will cause an unchecked cast warning, because you are, in fact, casting a RStarTreeFactory (without generics) into a RStarTreeFactory<DoubleVector> here.

Parameters:

clazz - Class

Method Detail

with

public ELKIBuilder<T> with(OptionID opt,
                           java.lang.Object value)

Add an option to the builder.

Parameters:

opt - Option ID (usually found in the Parameterizer class)

value - Value

Returns:

The same builder

with

public ELKIBuilder<T> with(OptionID opt)

Add a flag to the builder.

Parameters:

opt - Option ID (usually found in the Parameterizer class)

Returns:

The same builder

with

public ELKIBuilder<T> with(java.lang.String opt,
                           java.lang.Object value)

Add an option to the builder.

Parameters:

opt - Option ID (usually found in the Parameterizer class)

value - Value

Returns:

The same builder

with

public ELKIBuilder<T> with(java.lang.String opt)

Add a flag to the builder.

Parameters:

opt - Option ID (usually found in the Parameterizer class)

Returns:

The same builder

build

public <C extends T> C build()

Instantiate, consuming the parameter list. This will throw an AbortException if the parameters are incomplete, or build() is called twice. We lose some type safety here, for convenience. The type <C> is meant to be <T> with generics added only, which is necessary because generics are implemented by erasure in Java.

Type Parameters:

C - Output type

Returns:

Instance