org.op4j.functions.Get is a special functions class which allows the retrieval of attribute values through the execution of getter methods.
Here is an example: Imagine your application has a User class which contains a getName() method, returning a String. Let's get the names of all the users in a list:
List<User> users = ...; List<String> userNames = Op.on(users).map(Get.attrOfString("name")).get();
The attrOfX(...) methods in the Get class return the following functions:
Method | Returned function type |
attrOfBigDecimal() | Function<Object,BigDecimal> |
attrOfBigInteger() | Function<Object,BigInteger> |
attrOfBoolean() | Function<Object,Boolean> |
attrOfByte() | Function<Object,Byte> |
attrOfCalendar() | Function<Object,Calendar> |
attrOfCharacter() | Function<Object,Character> |
attrOfDate() | Function<Object,Date> |
attrOfDouble() | Function<Object,Double> |
attrOfFloat() | Function<Object,Float> |
attrOfInteger() | Function<Object,Integer> |
attrOfLong() | Function<Object,Long> |
attrOfObject() | Function<Object,Object> |
attrOfShort() | Function<Object,Short> |
attrOfString() | Function<Object,String> |
attrOf(Type<T>) | Function<Object,T> |
attrOfArrayOf(Type<T>) | Function<Object,T[]> |
attrOfArrayOfString() | Function<Object,String[]> |
attrOfListOf(Type<T>) | Function<Object,List<T>> |
attrOfListOfString() | Function<Object,List<String>> |
attrOfSetOf(Type<T>) | Function<Object,Set<T>> |
attrOfSetOfString() | Function<Object,Set<String>> |
There also exist more convenient abbreviated methods, which are:
Method | Returned function type |
bigDecimal() | Function<Object,BigDecimal> |
bigInteger() | Function<Object,BigInteger> |
bool() | Function<Object,Boolean> |
calendar() | Function<Object,Calendar> |
c() | Function<Object,Character> |
date() | Function<Object,Date> |
d() | Function<Object,Double> |
f() | Function<Object,Float> |
i() | Function<Object,Integer> |
l() | Function<Object,Long> |
obj() | Function<Object,Object> |
shr() | Function<Object,Short> |
s() | Function<Object,String> |
obj(Type<T>) | Function<Object,T> |
arrayOf(Type<T>) | Function<Object,T[]> |
arrayOfString() | Function<Object,String[]> |
listOf(Type<T>) | Function<Object,List<T>> |
listOfString() | Function<Object,List<String>> |
setOf(Type<T>) | Function<Object,Set<T>> |
setOfString() | Function<Object,Set<String>> |