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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.lens.lenses;

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.function.BiPredicate;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Predicate;

import functionalj.function.Func;
import functionalj.lens.core.AccessParameterized2;
import functionalj.lens.core.LensSpec;
import functionalj.lens.core.LensSpecParameterized2;
import functionalj.lens.core.LensUtils;
import functionalj.lens.core.WriteLens;
import functionalj.tuple.ImmutableTuple2;
import lombok.val;

@SuppressWarnings("javadoc")
public interface MapLens, 
                            VALUELENS extends AnyLens>
                    extends
                        ObjectLens>,
                        MapAccess {
    
    public static , VALUELENS extends AnyLens>
            MapLens of(
                    Function>           read,
                    WriteLens>           write,
                    Function,   KEYLENS>   keyLensCreator,
                    Function, VALUELENS> valueLensCreator) {
        val spec = LensUtils.createMapLensSpec(read, write, keyLensCreator, valueLensCreator);    
        return ()->spec;
    }
    
    public LensSpecParameterized2, KEY, VALUE, KEYLENS, VALUELENS> lensSpecParameterized2();
    
    @Override
    public default AccessParameterized2, KEY, VALUE, KEYLENS, VALUELENS> accessParameterized2() {
        return lensSpecParameterized2();
    }
    
    @Override
    public default LensSpec> lensSpec() {
        return lensSpecParameterized2().getSpec();
    }
    
    @Override
    public default Map applyUnsafe(HOST host) throws Exception {
        return ObjectLens.super.applyUnsafe(host);
    }
    
    public default VALUELENS get(KEY key) {
        WriteLens, VALUE> write = (map, value) -> {
            val newMap = new LinkedHashMap();
            newMap.putAll(map);
            newMap.put(key, value);
            return newMap;
        };
        Function, VALUE> read = map -> {
            return map.get(key);
        };
        return LensUtils.createSubLens(this, read, write, lensSpecParameterized2()::createSubLens2);
    }
    
    public default Function changeTo(Predicate checker, Function mapper) {
        val mapEntry = Func.from((Map.Entry each) ->{
            val key   = each.getKey();
            val value = each.getValue();
            if (!checker.test(key)) 
                return each;
            
            val newValue = mapper.apply(value);
            return (Map.Entry)new ImmutableTuple2(key, newValue);
        });
        
        val newMap = new LinkedHashMap();
        Consumer> transformEntry = entry -> {
            val key   = entry.getKey();
            val value = entry.getValue();
            if (!checker.test(key)) 
                newMap.put(key, value);
            else {
                val newValue = mapper.apply(value);
                newMap.put(key, newValue);
            }
        };
        return host -> {
            apply(host).entrySet().stream()
                    .map    (mapEntry)
                    .forEach(transformEntry);
            val newHost = apply(host, newMap);
            return newHost;
        };
    }
    
    public default Function changeTo(BiPredicate checker, Function mapper) {
        val mapEntry = Func.from((Map.Entry each) ->{
            val key   = each.getKey();
            val value = each.getValue();
            if (!checker.test(key, value)) 
                return each;
            
            val newValue = mapper.apply(value);
            return (Map.Entry)new ImmutableTuple2(key, newValue);
        });
        
        return host -> {
            val newMap = new LinkedHashMap();
            Consumer> transformEntry = entry -> {
                val key   = entry.getKey();
                val value = entry.getValue();
                if (!checker.test(key, value)) 
                    newMap.put(key, value);
                else {
                    val newValue = mapper.apply(value);
                    newMap.put(key, newValue);
                }
            };
            apply(host).entrySet().stream()
                    .map    (mapEntry)
                    .forEach(transformEntry);
            val newHost = apply(host, newMap);
            return newHost;
        };
    }
}