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Add swapMultiLevelMapKeys

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This commit is contained in:
darin.kelkhoff
2023-07-13 17:09:18 -05:00
parent de8d668ea2
commit 6d6510c223
2 changed files with 59 additions and 0 deletions
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36
qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/utils/CollectionUtils.java
View File

@ -627,4 +627,40 @@ public class CollectionUtils
}
}
/*******************************************************************************
** Take a multi-level map, e.g., Map{String, Map{Integer, BigDecimal}}
** and invert it - e.g., to Map{Integer, Map{String, BigDecimal}}
*******************************************************************************/
public static <K1, K2, V> Map<K2, Map<K1, V>> swapMultiLevelMapKeys(Map<K1, Map<K2, V>> input)
{
if(input == null)
{
return (null);
}
Map<K2, Map<K1, V>> output = new HashMap<>();
for(Map.Entry<K1, Map<K2, V>> entry : input.entrySet())
{
K1 key1 = entry.getKey();
Map<K2, V> map1 = entry.getValue();
if(map1 != null)
{
for(Map.Entry<K2, V> entry2 : map1.entrySet())
{
K2 key2 = entry2.getKey();
V value = entry2.getValue();
output.computeIfAbsent(key2, (k) -> new HashMap<>());
output.get(key2).put(key1, value);
}
}
}
return (output);
}
}

23
qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/utils/CollectionUtilsTest.java
View File

@ -34,6 +34,7 @@ import java.util.TreeMap;
import java.util.function.Function;
import com.google.gson.reflect.TypeToken;
import com.kingsrook.qqq.backend.core.BaseTest;
import com.kingsrook.qqq.backend.core.utils.collections.MapBuilder;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertEquals;
@ -594,4 +595,26 @@ class CollectionUtilsTest extends BaseTest
}
/*******************************************************************************
**
*******************************************************************************/
@Test
void testSwapMultiLevelMapKeys()
{
Map<String, Map<Integer, String>> input = MapBuilder.of(
"A", Map.of(1, "A1", 2, "A2", 3, "A3"),
"B", Map.of(1, "B1", 4, "B4"),
"C", null);
Map<Integer, Map<String, String>> output = CollectionUtils.swapMultiLevelMapKeys(input);
assertEquals(MapBuilder.of(
1, Map.of("A", "A1", "B", "B1"),
2, Map.of("A", "A2"),
3, Map.of("A", "A3"),
4, Map.of("B", "B4")), output);
}
}