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The module for FunctionalJ Core.
There is a newer version: 1.0.17
// ============================================================================
// Copyright (c) 2017-2019 Nawapunth Manusitthipol (NawaMan - http://nawaman.net).
// ----------------------------------------------------------------------------
// MIT License
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
// ============================================================================
package functionalj.functions;

import java.util.function.Function;
import java.util.function.Predicate;

import functionalj.function.Func1;
import functionalj.list.FuncList;
import functionalj.map.ImmutableMap;
import functionalj.tuple.ToMapFunc;
import functionalj.tuple.ToTuple2Func;
import functionalj.tuple.Tuple;
import lombok.val;

public class MapTo {
    
    public static  Func1 only(Predicate checker) {
        return input -> checker.test(input) ? input : null;
    }
    
    public static  Func1 forOnly(
            Predicate          checker,
            Func1 mapper) {
        return input -> checker.test(input) ? mapper.applyUnsafe(input) : input;
    }
    
    public static  Func1 when(
            Predicate             checker, 
            Function mapper, 
            Function elseMapper) {
        return input -> 
                checker.test(input)
                ? mapper.apply(input)
                : elseMapper.apply(input);
    }
    
    // FirstOf
    
    public static  Func1 firstOf(
            FuncList> mappers) {
        return input -> {
            Exception exception = null;
            boolean hasNull = false;
            for(val mapper : mappers) {
                try {
                    val res = mapper.apply(input);
                    if (res == null)
                         hasNull = true;
                    else return (T)res;
                } catch (Exception e) {
                    if (exception == null)
                        exception = e;
                }
            }
            if (hasNull)
                return (T)null;
            
            throw exception;
        };
    }
    
    @SafeVarargs
    public static  Func1 firstOf(
            Function ... mappers) {
        FuncList> mappersArray = FuncList.from(mappers);
        return firstOf(mappersArray);
    }
    
    // Tuple
    
    public static  ToTuple2Func toTuple(
            Func1 mapper1,
            Func1 mapper2) {
        return input -> {
            val v1 = mapper1.apply(input);
            val v2 = mapper2.apply(input);
            return Tuple.of(v1, v2);
        };
    }
    
    // Map
    
    public static  ToMapFunc toMap(
            K key, Func1 mapper) {
        return data -> ImmutableMap.of(key, mapper.apply(data));
    }
    
}