Modul speiger.src.collections
Package speiger.src.collections.doubles.maps.impl.misc

Klasse Double2BooleanArrayMap

java.lang.Object
java.util.AbstractMap<Double,Boolean>
speiger.src.collections.doubles.maps.abstracts.AbstractDouble2BooleanMap
speiger.src.collections.doubles.maps.impl.misc.Double2BooleanArrayMap
Alle implementierten Schnittstellen:
DoublePredicate, Map<Double,Boolean>, Double2BooleanMap, Double2BooleanOrderedMap
public class Double2BooleanArrayMap extends AbstractDouble2BooleanMap implements Double2BooleanOrderedMap
A Very Specific Type Specific implementation of a ArrayMap. This type of map is for very specific use cases that usaully would have lead to Tupled Lists otherwise. It also does not allow duplication (except for array constructors) and checks from last to first. It is not designed to be used as a HashMap replacement due to the poor performance it would cause.
Note:
in this implementation SubMaps do NOT keep track of parent changes fully. For performance reasons it will just have a start/end index and not values Anything within that range will be updated appropiatly a shrink/growth of elements will break SubMaps in some ways. This can be useful but be careful, this implementation does not shrink and only grows.

  • Konstruktordetails

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap()
      Default Constructor

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap(int minCapacity)
      Constructor that defines the minimum capacity
      Parameter:
      minCapacity - the minimum capacity the HashMap is allowed to be.
      Löst aus:
      IllegalStateException - if the minimum capacity is negative

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap(Double[] keys, Boolean[] values)
      Helper constructor that allow to create a map from boxed values (it will unbox them)
      Parameter:
      keys - the keys that should be put into the map
      values - the values that should be put into the map.
      Löst aus:
      IllegalStateException - if the keys and values do not match in length

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap(Double[] keys, Boolean[] values, int length)
      Helper constructor that allow to create a map from boxed values (it will unbox them) with a custom length
      Parameter:
      keys - the keys that should be put into the map
      values - the values that should be put into the map.
      length - the amount of values that should be pulled from the array
      Löst aus:
      IllegalStateException - if the keys and values do not match in length

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap(double[] keys, boolean[] values)
      Helper constructor that allow to create a map from unboxed values
      Parameter:
      keys - the keys that should be put into the map
      values - the values that should be put into the map.
      Löst aus:
      IllegalStateException - if the keys and values do not match in lenght

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap(double[] keys, boolean[] values, int length)
      Helper constructor that allow to create a map from unboxed values
      Parameter:
      keys - the keys that should be put into the map
      values - the values that should be put into the map.
      length - the amount of values that should be pulled from the array
      Löst aus:
      IllegalStateException - if the keys and values do not match in lenght

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap(Map<? extends Double,? extends Boolean> map)
      A Helper constructor that allows to create a Map with exactly the same values as the provided map.
      Parameter:
      map - the values that should be present in the map

    • Double2BooleanArrayMap

      public Double2BooleanArrayMap(Double2BooleanMap map)
      A Type Specific Helper function that allows to create a new Map with exactly the same values as the provided map.
      Parameter:
      map - the values that should be present in the map

  • Methodendetails

    • put

      public boolean put(double key, boolean value)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Specific method to reduce boxing/unboxing of values
      Angegeben von:
      put in Schnittstelle Double2BooleanMap
      Parameter:
      key - the key that should be inserted,
      value - the value that should be inserted
      Gibt zurück:
      the last present value or default return value.
      Siehe auch:

    • putIfAbsent

      public boolean putIfAbsent(double key, boolean value)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Specific method to reduce boxing/unboxing of values
      Angegeben von:
      putIfAbsent in Schnittstelle Double2BooleanMap
      Parameter:
      key - the key that should be inserted,
      value - the value that should be inserted
      Gibt zurück:
      the last present value or default return value.
      Siehe auch:

    • putAndMoveToFirst

      public boolean putAndMoveToFirst(double key, boolean value)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A customized put method that allows you to insert into the first index.
      Angegeben von:
      putAndMoveToFirst in Schnittstelle Double2BooleanOrderedMap
      Parameter:
      key - the key that should be inserted
      value - the value that should be inserted
      Gibt zurück:
      the previous present or default return value
      Siehe auch:

    • putAndMoveToLast

      public boolean putAndMoveToLast(double key, boolean value)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A customized put method that allows you to insert into the last index. (This may be nessesary depending on the implementation)
      Angegeben von:
      putAndMoveToLast in Schnittstelle Double2BooleanOrderedMap
      Parameter:
      key - the key that should be inserted
      value - the value that should be inserted
      Gibt zurück:
      the previous present or default return value
      Siehe auch:

    • moveToFirst

      public boolean moveToFirst(double key)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A specific move method to move a given key/value to the first index.
      Angegeben von:
      moveToFirst in Schnittstelle Double2BooleanOrderedMap
      Parameter:
      key - that should be moved to the first index
      Gibt zurück:
      true if the value was moved.

    • moveToLast

      public boolean moveToLast(double key)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A specific move method to move a given key/value to the last index.
      Angegeben von:
      moveToLast in Schnittstelle Double2BooleanOrderedMap
      Parameter:
      key - that should be moved to the first last
      Gibt zurück:
      true if the value was moved.

    • containsKey

      public boolean containsKey(double key)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Specific method to reduce boxing/unboxing of values
      Angegeben von:
      containsKey in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      containsKey in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - element that is searched for
      Gibt zurück:
      if the key is present

    • containsValue

      public boolean containsValue(boolean value)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Specific method to reduce boxing/unboxing of values
      Angegeben von:
      containsValue in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      containsValue in Klasse AbstractDouble2BooleanMap
      Parameter:
      value - element that is searched for
      Gibt zurück:
      if the value is present

    • containsKey

      public boolean containsKey(Object key)
      Angegeben von:
      containsKey in Schnittstelle Double2BooleanMap
      Angegeben von:
      containsKey in Schnittstelle Map<Double,Boolean>
      Setzt außer Kraft:
      containsKey in Klasse AbstractMap<Double,Boolean>
      Parameter:
      key - that is searched for.
      Gibt zurück:
      true if found
      Siehe auch:

    • containsValue

      public boolean containsValue(Object value)
      Angegeben von:
      containsValue in Schnittstelle Double2BooleanMap
      Angegeben von:
      containsValue in Schnittstelle Map<Double,Boolean>
      Setzt außer Kraft:
      containsValue in Klasse AbstractMap<Double,Boolean>
      Parameter:
      value - that is searched for.
      Gibt zurück:
      true if found
      Siehe auch:

    • get

      public boolean get(double key)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific get method to reduce boxing/unboxing
      Angegeben von:
      get in Schnittstelle Double2BooleanMap
      Parameter:
      key - the key that is searched for
      Gibt zurück:
      the searched value or default return value

    • getOrDefault

      public boolean getOrDefault(double key, boolean defaultValue)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific getOrDefault method to reduce boxing/unboxing
      Angegeben von:
      getOrDefault in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      getOrDefault in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that is searched for
      defaultValue - the value that should be returned if the key is not present
      Gibt zurück:
      the searched value or defaultValue value

    • getAndMoveToFirst

      public boolean getAndMoveToFirst(double key)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A Specific get method that allows to move teh given key/value int the first index.
      Angegeben von:
      getAndMoveToFirst in Schnittstelle Double2BooleanOrderedMap
      Parameter:
      key - that is searched for
      Gibt zurück:
      the given value for the requested key or default return value

    • getAndMoveToLast

      public boolean getAndMoveToLast(double key)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A Specific get method that allows to move teh given key/value int the last index.
      Angegeben von:
      getAndMoveToLast in Schnittstelle Double2BooleanOrderedMap
      Parameter:
      key - that is searched for
      Gibt zurück:
      the given value for the requested key or default return value

    • firstDoubleKey

      public double firstDoubleKey()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A method to get the first Key of a Map.
      Angegeben von:
      firstDoubleKey in Schnittstelle Double2BooleanOrderedMap
      Gibt zurück:
      the first key in the map

    • lastDoubleKey

      public double lastDoubleKey()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A method to get the last Key of a Map.
      Angegeben von:
      lastDoubleKey in Schnittstelle Double2BooleanOrderedMap
      Gibt zurück:
      the last key in the map

    • firstBooleanValue

      public boolean firstBooleanValue()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A method to get the first Value of a Map.
      Angegeben von:
      firstBooleanValue in Schnittstelle Double2BooleanOrderedMap
      Gibt zurück:
      the first key in the map

    • lastBooleanValue

      public boolean lastBooleanValue()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A method to get the last Value of a Map.
      Angegeben von:
      lastBooleanValue in Schnittstelle Double2BooleanOrderedMap
      Gibt zurück:
      the last key in the map

    • pollFirstDoubleKey

      public double pollFirstDoubleKey()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A method to get and remove the first Key of a Map.
      Angegeben von:
      pollFirstDoubleKey in Schnittstelle Double2BooleanOrderedMap
      Gibt zurück:
      the first key in the map

    • pollLastDoubleKey

      public double pollLastDoubleKey()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanOrderedMap
      A method to get and remove the last Key of a Map.
      Angegeben von:
      pollLastDoubleKey in Schnittstelle Double2BooleanOrderedMap
      Gibt zurück:
      the last key in the map

    • remove

      public boolean remove(double key)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Specific remove function to reduce boxing/unboxing
      Angegeben von:
      remove in Schnittstelle Double2BooleanMap
      Parameter:
      key - the element that should be removed
      Gibt zurück:
      the value that was removed or default return value

    • removeOrDefault

      public boolean removeOrDefault(double key, boolean defaultValue)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type-Specific Remove function with a default return value if wanted.
      Angegeben von:
      removeOrDefault in Schnittstelle Double2BooleanMap
      Parameter:
      key - the element that should be removed
      defaultValue - the value that should be returned if the entry doesn't exist
      Gibt zurück:
      the value that was removed or default value
      Siehe auch:

    • remove

      public boolean remove(double key, boolean value)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Specific remove function to reduce boxing/unboxing
      Angegeben von:
      remove in Schnittstelle Double2BooleanMap
      Parameter:
      key - the element that should be removed
      value - the expected value that should be found
      Gibt zurück:
      true if the key and value was found and removed
      Siehe auch:

    • remove

      public Boolean remove(Object key)
      Angegeben von:
      remove in Schnittstelle Double2BooleanMap
      Angegeben von:
      remove in Schnittstelle Map<Double,Boolean>
      Setzt außer Kraft:
      remove in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the element that should be removed
      Gibt zurück:
      the value that was removed or default return value
      Siehe auch:

    • remove

      public boolean remove(Object key, Object value)
      Angegeben von:
      remove in Schnittstelle Double2BooleanMap
      Angegeben von:
      remove in Schnittstelle Map<Double,Boolean>
      Parameter:
      key - the element that should be removed
      value - the expected value that should be found
      Gibt zurück:
      true if the key and value was found and removed
      Siehe auch:

    • forEach

      public void forEach(DoubleBooleanConsumer action)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Specific forEach method to reduce boxing/unboxing
      Angegeben von:
      forEach in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      forEach in Klasse AbstractDouble2BooleanMap
      Parameter:
      action - processor of the values that are iterator over

    • keySet

      public DoubleOrderedSet keySet()
      Angegeben von:
      keySet in Schnittstelle Double2BooleanMap
      Angegeben von:
      keySet in Schnittstelle Double2BooleanOrderedMap
      Angegeben von:
      keySet in Schnittstelle Map<Double,Boolean>
      Setzt außer Kraft:
      keySet in Klasse AbstractDouble2BooleanMap

    • values

      public BooleanCollection values()
      Angegeben von:
      values in Schnittstelle Double2BooleanMap
      Angegeben von:
      values in Schnittstelle Map<Double,Boolean>
      Setzt außer Kraft:
      values in Klasse AbstractDouble2BooleanMap

    • double2BooleanEntrySet

      public ObjectOrderedSet<Double2BooleanMap.Entry> double2BooleanEntrySet()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      Type Sensitive EntrySet to reduce boxing/unboxing and optionally Temp Object Allocation.
      Angegeben von:
      double2BooleanEntrySet in Schnittstelle Double2BooleanMap
      Angegeben von:
      double2BooleanEntrySet in Schnittstelle Double2BooleanOrderedMap
      Gibt zurück:
      a EntrySet of the collection

    • replace

      public boolean replace(double key, boolean oldValue, boolean newValue)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific replace method to replace an existing value
      Angegeben von:
      replace in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      replace in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the element that should be searched for
      oldValue - the expected value to be replaced
      newValue - the value to replace the oldValue with.
      Gibt zurück:
      true if the value got replaced

    • replace

      public boolean replace(double key, boolean value)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific replace method to reduce boxing/unboxing replace an existing value
      Angegeben von:
      replace in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      replace in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the element that should be searched for
      value - the value to replace with.
      Gibt zurück:
      the present value or default return value

    • computeBoolean

      public boolean computeBoolean(double key, DoubleBooleanUnaryOperator mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific compute method to reduce boxing/unboxing If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      computeBoolean in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      computeBoolean in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      mappingFunction - the operator that should generate the value
      Gibt zurück:
      the result of the computation

    • computeBooleanIfAbsent

      public boolean computeBooleanIfAbsent(double key, DoublePredicate mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific computeIfAbsent method to reduce boxing/unboxing If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      computeBooleanIfAbsent in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      computeBooleanIfAbsent in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      mappingFunction - the operator that should generate the value if not present
      Gibt zurück:
      the result of the computed value or present value

    • supplyBooleanIfAbsent

      public boolean supplyBooleanIfAbsent(double key, BooleanSupplier valueProvider)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Supplier based computeIfAbsent function to fill the most used usecase of this function If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      supplyBooleanIfAbsent in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      supplyBooleanIfAbsent in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      valueProvider - the value if not present
      Gibt zurück:
      the result of the computed value or present value

    • computeBooleanIfPresent

      public boolean computeBooleanIfPresent(double key, DoubleBooleanUnaryOperator mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific compute method to reduce boxing/unboxing If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      computeBooleanIfPresent in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      computeBooleanIfPresent in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      mappingFunction - the operator that should generate the value if present
      Gibt zurück:
      the result of the default return value or present value

    • computeBooleanNonDefault

      public boolean computeBooleanNonDefault(double key, DoubleBooleanUnaryOperator mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific compute method to reduce boxing/unboxing If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      computeBooleanNonDefault in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      computeBooleanNonDefault in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      mappingFunction - the operator that should generate the value
      Gibt zurück:
      the result of the computation

    • computeBooleanIfAbsentNonDefault

      public boolean computeBooleanIfAbsentNonDefault(double key, DoublePredicate mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific computeIfAbsent method to reduce boxing/unboxing If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      computeBooleanIfAbsentNonDefault in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      computeBooleanIfAbsentNonDefault in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      mappingFunction - the operator that should generate the value if not present
      Gibt zurück:
      the result of the computed value or present value

    • supplyBooleanIfAbsentNonDefault

      public boolean supplyBooleanIfAbsentNonDefault(double key, BooleanSupplier valueProvider)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Supplier based computeIfAbsent function to fill the most used usecase of this function If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      supplyBooleanIfAbsentNonDefault in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      supplyBooleanIfAbsentNonDefault in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      valueProvider - the value if not present
      Gibt zurück:
      the result of the computed value or present value

    • computeBooleanIfPresentNonDefault

      public boolean computeBooleanIfPresentNonDefault(double key, DoubleBooleanUnaryOperator mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific compute method to reduce boxing/unboxing If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      computeBooleanIfPresentNonDefault in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      computeBooleanIfPresentNonDefault in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be computed
      mappingFunction - the operator that should generate the value if present
      Gibt zurück:
      the result of the default return value or present value

    • mergeBoolean

      public boolean mergeBoolean(double key, boolean value, BooleanBooleanUnaryOperator mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Type Specific merge method to reduce boxing/unboxing If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      mergeBoolean in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      mergeBoolean in Klasse AbstractDouble2BooleanMap
      Parameter:
      key - the key that should be be searched for
      value - the value that should be merged with
      mappingFunction - the operator that should generate the new Value
      Gibt zurück:
      the result of the merge

    • mergeAllBoolean

      public void mergeAllBoolean(Double2BooleanMap m, BooleanBooleanUnaryOperator mappingFunction)
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Bulk method for merging Maps. If the generated value equals the getDefaultReturnValue it will simply not insert it since that is treated as "null". A "Null Value" will be treated as "Do not insert/remove" based on how the Java has specified it.
      Angegeben von:
      mergeAllBoolean in Schnittstelle Double2BooleanMap
      Setzt außer Kraft:
      mergeAllBoolean in Klasse AbstractDouble2BooleanMap
      Parameter:
      m - the entries that should be bulk added
      mappingFunction - the operator that should generate the new Value

    • size

      public int size()
      Angegeben von:
      size in Schnittstelle Map<Double,Boolean>
      Setzt außer Kraft:
      size in Klasse AbstractMap<Double,Boolean>

    • clear

      public void clear()
      Angegeben von:
      clear in Schnittstelle Map<Double,Boolean>
      Setzt außer Kraft:
      clear in Klasse AbstractMap<Double,Boolean>

    • copy

      public Double2BooleanArrayMap copy()
      Beschreibung aus Schnittstelle kopiert: Double2BooleanMap
      A Function that does a shallow clone of the Map itself. This function is more optimized then a copy constructor since the Map does not have to be unsorted/resorted. It can be compared to Cloneable but with less exception risk
      Angegeben von:
      copy in Schnittstelle Double2BooleanMap
      Angegeben von:
      copy in Schnittstelle Double2BooleanOrderedMap
      Setzt außer Kraft:
      copy in Klasse AbstractDouble2BooleanMap
      Gibt zurück:
      a Shallow Copy of the Map