Moved MapFromValueConverter from jenax to aksw-commons

aksw-commons-collections/src/main/java/org/aksw/commons/collections/maps/MapFromValueConverter.java

@@ -0,0 +1,66 @@
+package org.aksw.commons.collections.maps;
+
+import java.util.AbstractMap;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+
+import org.aksw.commons.collections.ConvertingCollection;
+import org.aksw.commons.collections.sets.SetFromCollection;
+
+import com.google.common.base.Converter;
+
+public class MapFromValueConverter<K, U, V>
+	extends AbstractMap<K, V>
+{
+	protected Map<K, U> map;
+	protected Converter<U, V> converter;
+
+	public MapFromValueConverter(Map<K, U> map, Converter<U, V> converter) {
+		super();
+		this.map = map;
+		this.converter = converter;
+	}
+
+	@Override
+	public V get(Object key) {
+		V result = Optional.ofNullable(map.get(key)).map(converter::convert).orElse(null);
+		return result;
+	}
+
+	@Override
+	public boolean containsKey(Object key) {
+		boolean result = map.containsKey(key);
+		return result;
+	}
+
+	@Override
+	public V put(K key, V value) {
+		U val = converter.reverse().convert(value);
+		map.put(key, val);
+		return value;
+	}
+
+	@Override
+	public boolean containsValue(Object value) {
+		U val = converter.reverse().convert((V)value);
+		boolean result = map.containsValue(val);
+		return result;
+	}
+
+	@Override
+	public Collection<V> values() {
+		return new ConvertingCollection<>(map.values(), converter);
+	}
+
+	// public static <K, L> Entry<L, V> transform(Entry<K, V>, Function<? super K, ?
+	// extends V> )
+
+	@Override
+	public Set<Entry<K, V>> entrySet() {
+		return new SetFromCollection<>(
+				new ConvertingCollection<>(map.entrySet(), EntryConverterByKey.converterByValue(converter)));
+	}
+
+}