Package com.tangosol.util

Class Extractors

java.lang.Object

com.tangosol.util.Extractors

public class Extractors
extends Object

Simple Extractor DSL.

The methods in this class are for the most part simple factory methods for various ValueExtractor classes, but in some cases provide additional type safety. They also tend to make the code more readable, especially if imported statically, so their use is strongly encouraged in lieu of direct construction of Extractor classes.

Author:

lh, hr, as, mf 2018.06.14

Constructor Summary

Constructors

Constructor	Description
Extractors()

Method Summary

Modifier and Type	Method	Description
static <T,R> ValueExtractor<T,R>	chained(ValueExtractor<?,?>... extractors)	Returns an extractor that extracts the specified fields where extraction occurs in a chain where the result of each field extraction is the input to the next extractor.
static <T,R> ValueExtractor<T,R>	chained(String... fields)	Returns an extractor that extracts the specified fields where extraction occurs in a chain where the result of each field extraction is the input to the next extractor.
static <T,E> ValueExtractor<T,E>	extract(String from)	Returns an extractor that extracts the value of the specified field.
static <T,E> ValueExtractor<T,E>	extract(String from, Object... aoParam)	Returns an extractor that extracts the value of the specified field.
static <T> ValueExtractor<T,Fragment<T>>	fragment(ValueExtractor<? super T,?>... aExtractors)	Return a ValueExtractor that extracts a Fragment from a target object.
static <T,E> ValueExtractor<T,Fragment<E>>	fragment(ValueExtractor<? super T,E> from, ValueExtractor<? super E,?>... aExtractors)	Return a ValueExtractor that extracts a nested Fragment from a property of the target object.
static <T> ValueExtractor<T,?>	fromPof(int... indexes)	Returns an extractor that extracts the value of the specified index(es) from a POF encoded binary value.
static <T,E> ValueExtractor<T,E>	fromPof(Class<E> cls, int... indexes)	Returns an extractor that extracts the value of the specified index(es) from a POF encoded binary value.
static <T,E> ValueExtractor<T,E>	fromPof(Class<E> cls, PofNavigator navigator)	Returns an extractor that extracts the value of the specified index(es) from a POF encoded binary value.
static <T,E> ValueExtractor<T,E>	fromPof(Class<E> cls, String sPath)	Returns an extractor that extracts the value of the specified index(es) from a POF encoded @PortableType.
static <T> ValueExtractor<T,T>	identity()	Returns an extractor that always returns its input argument.
static <T,E> ValueExtractor<T,E>	identityCast()	Returns an extractor that casts its input argument.
static <T> ValueExtractor<T,List<?>>	multi(ValueExtractor<T,?>... extractors)	Returns an extractor that extracts values using the specified ValueExtractors and returns the extracted values in a List.
static <T> ValueExtractor<T,List<?>>	multi(String... fields)	Returns an extractor that extracts the specified fields and returns the extracted values in a List.
static <T,E> ValueExtractor<T,E>	script(String sLanguage, String sScriptPath, Object... aoArgs)	Instantiate a ValueExtractor that is implemented using the specified language.

Methods inherited from class java.lang.Object

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

Constructor Detail

Extractors

public Extractors()

Method Detail

identity

public static <T> ValueExtractor<T,T> identity()

Returns an extractor that always returns its input argument.

Type Parameters:

T - the type of the input and output objects to the function

Returns:

an extractor that always returns its input argument

extract

public static <T,E> ValueExtractor<T,E> extract(String from)

Returns an extractor that extracts the value of the specified field.

Type Parameters:

T - the type of the object to extract from

E - the type of the extracted value

Parameters:

from - the name of the field or method to extract the value from

Returns:

an extractor that extracts the value of the specified field

See Also:

UniversalExtractor

extract

public static <T,E> ValueExtractor<T,E> extract(String from,
                                                            Object... aoParam)

Returns an extractor that extracts the value of the specified field.

Type Parameters:

T - the type of the object to extract from

E - the type of the extracted value

Parameters:

from - the name of the method to extract the value from (which must be the full method name)

aoParam - the parameters to pass to the method

Returns:

an extractor that extracts the value of the specified field

See Also:

UniversalExtractor

multi

public static <T> ValueExtractor<T,List<?>> multi(String... fields)

Returns an extractor that extracts the specified fields and returns the extracted values in a List.

Type Parameters:

T - the type of the object to extract from

Parameters:

fields - the field names to extract

Returns:

an extractor that extracts the value(s) of the specified field(s)

Throws:

IllegalArgumentException - if the fields parameter is null or an empty array

See Also:

UniversalExtractor

multi

public static <T> ValueExtractor<T,List<?>> multi(ValueExtractor<T,?>... extractors)

Returns an extractor that extracts values using the specified ValueExtractors and returns the extracted values in a List.

Type Parameters:

T - the type of the object to extract from

Parameters:

extractors - the ValueExtractors to use to extract the list of values

Returns:

an extractor that extracts the value(s) of the specified field(s)

Throws:

IllegalArgumentException - if the fields parameter is null or an empty array

See Also:

UniversalExtractor

chained

public static <T,R> ValueExtractor<T,R> chained(String... fields)

Returns an extractor that extracts the specified fields where extraction occurs in a chain where the result of each field extraction is the input to the next extractor. The result returned is the result of the final extractor in the chain.

Type Parameters:

T - the type of the object to extract from

Parameters:

fields - the field names to extract (if any field name contains a dot '.' that field name is split into multiple field names delimiting on the dots.

Returns:

an extractor that extracts the value(s) of the specified field(s)

Throws:

IllegalArgumentException - if the fields parameter is null or an empty array

See Also:

UniversalExtractor

chained

public static <T,R> ValueExtractor<T,R> chained(ValueExtractor<?,?>... extractors)

Returns an extractor that extracts the specified fields where extraction occurs in a chain where the result of each field extraction is the input to the next extractor. The result returned is the result of the final extractor in the chain.

Type Parameters:

T - the type of the object to extract from

Parameters:

extractors - the ValueExtractors to use to extract the list of values

Returns:

an extractor that extracts the value(s) of the specified field(s)

Throws:

IllegalArgumentException - if the extractors parameter is null or an empty array

See Also:

UniversalExtractor

identityCast

public static <T,E> ValueExtractor<T,E> identityCast()

Returns an extractor that casts its input argument.

Type Parameters:

T - the type of the input objects to the function

E - the type of the output objects to the function

Returns:

an extractor that always returns its input argument

fromPof

public static <T> ValueExtractor<T,?> fromPof(int... indexes)

Returns an extractor that extracts the value of the specified index(es) from a POF encoded binary value.

Type Parameters:

T - the type of the object to extract from

Parameters:

indexes - the POF index(es) to extract

Returns:

an extractor that extracts the value of the specified field

fromPof

public static <T,E> ValueExtractor<T,E> fromPof(Class<E> cls,
                                                            int... indexes)

Returns an extractor that extracts the value of the specified index(es) from a POF encoded binary value.

Type Parameters:

T - the type of the POF serialized object to extract from

E - the type of the extracted value

Parameters:

indexes - the POF index(es) to extract

Returns:

an extractor that extracts the value of the specified field

Throws:

NullPointerException - if the indexes parameter is null

fromPof

public static <T,E> ValueExtractor<T,E> fromPof(Class<E> cls,
                                                            String sPath)

Returns an extractor that extracts the value of the specified index(es) from a POF encoded @PortableType.

The specified class *must* be marked with @PortableType annotation and instrumented using PortableTypeGenerator in order for this method to work. Otherwise, an IllegalArgumentException will be thrown.

Type Parameters:

T - the type of the POF serialized object to extract from

E - the type of the extracted value

Parameters:

sPath - the path of the property to extract

Returns:

an extractor that extracts the value of the specified field

Throws:

NullPointerException - if the indexes parameter is null

IllegalArgumentException - if the specified class isn't a portable type, or the specified property path doesn't exist

fromPof

public static <T,E> ValueExtractor<T,E> fromPof(Class<E> cls,
                                                            PofNavigator navigator)

Returns an extractor that extracts the value of the specified index(es) from a POF encoded binary value.

Type Parameters:

T - the type of the POF serialized object to extract from

E - the type of the extracted value

Parameters:

navigator - the PofNavigator to use to determine the POF path to extract

Returns:

an extractor that extracts the value of the specified field

Throws:

NullPointerException - if the indexes parameter is null

script

public static <T,E> ValueExtractor<T,E> script(String sLanguage,
                                                           String sScriptPath,
                                                           Object... aoArgs)

Instantiate a ValueExtractor that is implemented using the specified language.

Type Parameters:

T - the type of object to extract from

E - the type of the extracted value

Parameters:

sLanguage - the string specifying one of the supported languages

sScriptPath - the path where the script reside, relative to root

aoArgs - the arguments to be passed to the script

Returns:

An instance of ValueExtractor

Throws:

ScriptException - if the script cannot be loaded or any errors occur during its execution

IllegalArgumentException - if the specified language is not supported

Since:

14.1.1.0

fragment

@SafeVarargs
public static <T> ValueExtractor<T,Fragment<T>> fragment(ValueExtractor<? super T,?>... aExtractors)

Return a ValueExtractor that extracts a Fragment from a target object.

Type Parameters:

T - the type of object to extract from

Parameters:

aExtractors - an array of extractors to pass to FragmentExtractor

Returns:

a ValueExtractor that extracts a Fragment from a target object

fragment

@SafeVarargs
public static <T,E> ValueExtractor<T,Fragment<E>> fragment(ValueExtractor<? super T,E> from,
                                                                       ValueExtractor<? super E,?>... aExtractors)

Return a ValueExtractor that extracts a nested Fragment from a property of the target object.

Type Parameters:

T - the type of the root object to extract from

Parameters:

from - an extractor for the nested property to extract the fragment from

aExtractors - an array of extractors to pass to FragmentExtractor

Returns:

a ValueExtractor that extracts a Fragment from a target object's property