New Compute function and better toArray implementations

Changelog.md

@@ -1,5 +1,13 @@
 # Changelog of versions
 
+### Version 0.8.1
+- Added: getFirst/getLast/removeFirst/removeLast to List.class.
+- Added: Dedicated Set toArray implementations.
+- Added: ToArray/pushTop functions to Stack.class.
+- Added: ComputeNonDefault functions which will contain the current behavior of the Compute function, while the Compute will be changed to be more java compliant!
+- Fixed: SetValue wasn't working on forEach implementations.
+
+
 ### Version 0.8.0
 - Added: getFirst/getLast/removeFirst/removeLast to Lists
 - Added: Dedicated implementations for toArray into TreeSets

src/builder/resources/speiger/assets/collections/templates/collections/Stack.template

@@ -1,5 +1,7 @@
 package speiger.src.collections.PACKAGE.collections;
 
+import java.util.NoSuchElementException;
+
 import speiger.src.collections.utils.Stack;
 
 /**
@@ -14,6 +16,14 @@ public interface STACK
 	 */
 	public void push(KEY_TYPE e);
 	
+	/**
+	 * Helper function that pushes the top element on top of the stack again.
+	 * @throws NoSuchElementException if the stack is empty
+	 */
+	public default void pushTop() {
+		push(top());
+	}
+	
 	/**
 	 * Removes the Object on top of the stack.
 	 * @return the element that is on top of the stack
@@ -59,4 +69,19 @@ public interface STACK
 	public default boolean isEmpty() {
 		return size() == 0;
 	}
+	
+	/**
+	 * A method to drop the contents of the Stack without clearing the stack
+	 * @Type(E)
+	 * @return the contents of the stack into a seperate array.
+	 */
+	public default GENERIC_SPECIAL_KEY_BRACES<E> KEY_SPECIAL_TYPE[] TO_ARRAY() { return TO_ARRAY(NEW_SPECIAL_KEY_ARRAY(size())); }
+	/**
+	 * A method to drop the contents of the Stack without clearing the stack
+	 * @param input where the elements should be inserted to. If it does not fit then it creates a new appropiatly created array
+	 * @Type(E)
+	 * @return the contents of the stack into a seperate array.
+	 * @note if the Type is generic then a Object Array is created instead of a Type Array
+	 */
+	public GENERIC_SPECIAL_KEY_BRACES<E> KEY_SPECIAL_TYPE[] TO_ARRAY(KEY_SPECIAL_TYPE[] input);
 }

src/builder/resources/speiger/assets/collections/templates/maps/abstracts/AbstractMap.template

@@ -201,6 +201,26 @@ public abstract class ABSTRACT_MAP KEY_VALUE_GENERIC_TYPE extends AbstractMap<CL
 	@Override
 	public VALUE_TYPE COMPUTE(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction) {
 		Objects.requireNonNull(mappingFunction);
+#if !VALUE_OBJECT
+		VALUE_TYPE newValue = mappingFunction.APPLY_VALUE(key, GET_VALUE(key));
+#else
+		VALUE_TYPE value = GET_VALUE(key);
+		VALUE_TYPE newValue = mappingFunction.APPLY_VALUE(key, value);
+		if(VALUE_EQUALS(newValue, getDefaultReturnValue())) {
+			if(VALUE_EQUALS_NOT(value, getDefaultReturnValue()) || containsKey(key)) {
+				remove(key);
+				return getDefaultReturnValue();
+			}
+			return getDefaultReturnValue();
+		}
+#endif
+		put(key, newValue);
+		return newValue;
+	}
+	
+	@Override
+	public VALUE_TYPE COMPUTENonDefault(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction) {
+		Objects.requireNonNull(mappingFunction);
 		VALUE_TYPE value = GET_VALUE(key);
 		VALUE_TYPE newValue = mappingFunction.APPLY_VALUE(key, value);
 		if(VALUE_EQUALS(newValue, getDefaultReturnValue())) {
@@ -217,6 +237,29 @@ public abstract class ABSTRACT_MAP KEY_VALUE_GENERIC_TYPE extends AbstractMap<CL
 	@Override
 	public VALUE_TYPE COMPUTE_IF_ABSENT(KEY_TYPE key, FUNCTION KEY_VALUE_GENERIC_TYPE mappingFunction) {
 		Objects.requireNonNull(mappingFunction);
+#if VALUE_OBJECT
+		VALUE_TYPE value;
+		if((value = GET_VALUE(key)) == getDefaultReturnValue() || !containsKey(key)) {
+			VALUE_TYPE newValue = mappingFunction.APPLY(key);
+			if(VALUE_EQUALS_NOT(newValue, getDefaultReturnValue())) {
+				put(key, newValue);
+				return newValue;
+			}
+		}
+		return value;
+#else
+		if(!containsKey(key)) {
+			VALUE_TYPE newValue = mappingFunction.APPLY(key);
+			put(key, newValue);
+			return newValue;
+		}
+		return get(key);
+#endif
+	}
+	
+	@Override
+	public VALUE_TYPE COMPUTE_IF_ABSENTNonDefault(KEY_TYPE key, FUNCTION KEY_VALUE_GENERIC_TYPE mappingFunction) {
+		Objects.requireNonNull(mappingFunction);
 		VALUE_TYPE value;
 		if((value = GET_VALUE(key)) == getDefaultReturnValue() || !containsKey(key)) {
 			VALUE_TYPE newValue = mappingFunction.APPLY(key);
@@ -231,6 +274,29 @@ public abstract class ABSTRACT_MAP KEY_VALUE_GENERIC_TYPE extends AbstractMap<CL
 	@Override
 	public VALUE_TYPE SUPPLY_IF_ABSENT(KEY_TYPE key, VALUE_SUPPLIER VALUE_GENERIC_TYPE valueProvider) {
 		Objects.requireNonNull(valueProvider);
+#if VALUE_OBJECT
+		VALUE_TYPE value;
+		if((value = GET_VALUE(key)) == getDefaultReturnValue() || !containsKey(key)) {
+			VALUE_TYPE newValue = valueProvider.VALUE_SUPPLY_GET();
+			if(VALUE_EQUALS_NOT(newValue, getDefaultReturnValue())) {
+				put(key, newValue);
+				return newValue;
+			}
+		}
+		return value;
+#else
+		if(!containsKey(key)) {
+			VALUE_TYPE newValue = valueProvider.VALUE_SUPPLY_GET();
+			put(key, newValue);
+			return newValue;
+		}
+		return get(key);
+#endif
+	}
+	
+	@Override
+	public VALUE_TYPE SUPPLY_IF_ABSENTNonDefault(KEY_TYPE key, VALUE_SUPPLIER VALUE_GENERIC_TYPE valueProvider) {
+		Objects.requireNonNull(valueProvider);
 		VALUE_TYPE value;
 		if((value = GET_VALUE(key)) == getDefaultReturnValue() || !containsKey(key)) {
 			VALUE_TYPE newValue = valueProvider.VALUE_SUPPLY_GET();
@@ -245,6 +311,29 @@ public abstract class ABSTRACT_MAP KEY_VALUE_GENERIC_TYPE extends AbstractMap<CL
 	@Override
 	public VALUE_TYPE COMPUTE_IF_PRESENT(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction) {
 		Objects.requireNonNull(mappingFunction);
+#if VALUE_OBJECT
+		VALUE_TYPE value;
+		if(VALUE_EQUALS_NOT((value = GET_VALUE(key)), getDefaultReturnValue()) || containsKey(key)) {
+			VALUE_TYPE newValue = mappingFunction.APPLY_VALUE(key, value);
+			if(VALUE_EQUALS_NOT(newValue, getDefaultReturnValue())) {
+				put(key, newValue);
+				return newValue;
+			}
+			remove(key);
+		}
+#else
+		if(containsKey(key)) {
+			VALUE_TYPE newValue = mappingFunction.APPLY_VALUE(key, GET_VALUE(key));
+			put(key, newValue);
+			return newValue;
+		}
+#endif
+		return getDefaultReturnValue();
+	}
+	
+	@Override
+	public VALUE_TYPE COMPUTE_IF_PRESENTNonDefault(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction) {
+		Objects.requireNonNull(mappingFunction);
 		VALUE_TYPE value;
 		if(VALUE_EQUALS_NOT((value = GET_VALUE(key)), getDefaultReturnValue()) || containsKey(key)) {
 			VALUE_TYPE newValue = mappingFunction.APPLY_VALUE(key, value);

src/builder/resources/speiger/assets/collections/templates/maps/interfaces/Map.template

@@ -389,6 +389,15 @@ public interface MAP KEY_VALUE_GENERIC_TYPE extends Map<CLASS_TYPE, CLASS_VALUE_
 	 * @return the result of the computation
 	 */
 	public VALUE_TYPE COMPUTE(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction);
+	/**
+	 * 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.
+	 * @param key the key that should be computed
+	 * @param mappingFunction the operator that should generate the value
+	 * @return the result of the computation
+	 */
+	public VALUE_TYPE COMPUTENonDefault(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction);
 	/**
 	 * 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".
@@ -398,7 +407,15 @@ public interface MAP KEY_VALUE_GENERIC_TYPE extends Map<CLASS_TYPE, CLASS_VALUE_
 	 * @return the result of the computed value or present value
 	 */
 	public VALUE_TYPE COMPUTE_IF_ABSENT(KEY_TYPE key, FUNCTION KEY_VALUE_GENERIC_TYPE mappingFunction);
-	
+	/**
+	 * 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.
+	 * @param key the key that should be computed
+	 * @param mappingFunction the operator that should generate the value if not present
+	 * @return the result of the computed value or present value
+	 */
+	public VALUE_TYPE COMPUTE_IF_ABSENTNonDefault(KEY_TYPE key, FUNCTION KEY_VALUE_GENERIC_TYPE mappingFunction);
 	/**
 	 * 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".
@@ -408,6 +425,15 @@ public interface MAP KEY_VALUE_GENERIC_TYPE extends Map<CLASS_TYPE, CLASS_VALUE_
 	 * @return the result of the computed value or present value
 	 */	
 	public VALUE_TYPE SUPPLY_IF_ABSENT(KEY_TYPE key, VALUE_SUPPLIER VALUE_GENERIC_TYPE valueProvider);
+	/**
+	 * 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.
+	 * @param key the key that should be computed
+	 * @param valueProvider the value if not present
+	 * @return the result of the computed value or present value
+	 */	
+	public VALUE_TYPE SUPPLY_IF_ABSENTNonDefault(KEY_TYPE key, VALUE_SUPPLIER VALUE_GENERIC_TYPE valueProvider);
 	/**
 	 * 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".
@@ -418,6 +444,16 @@ public interface MAP KEY_VALUE_GENERIC_TYPE extends Map<CLASS_TYPE, CLASS_VALUE_
 	 * @note if not present then compute is not executed
 	 */
 	public VALUE_TYPE COMPUTE_IF_PRESENT(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction);
+	/**
+	 * 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.
+	 * @param key the key that should be computed
+	 * @param mappingFunction the operator that should generate the value if present
+	 * @return the result of the default return value or present value
+	 * @note if not present then compute is not executed
+	 */
+	public VALUE_TYPE COMPUTE_IF_PRESENTNonDefault(KEY_TYPE key, UNARY_OPERATOR KEY_VALUE_GENERIC_TYPE mappingFunction);
 	/**
 	 * 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".

src/builder/resources/speiger/assets/collections/templates/sets/ImmutableOpenHashSet.template

@@ -27,6 +27,9 @@ import speiger.src.collections.PACKAGE.functions.function.PREDICATE;
 import speiger.src.collections.PACKAGE.functions.function.UNARY_OPERATOR;
 import speiger.src.collections.PACKAGE.lists.LIST_ITERATOR;
 import speiger.src.collections.PACKAGE.utils.ARRAYS;
+#if !TYPE_OBJECT
+import speiger.src.collections.objects.utils.ObjectArrays;
+#endif
 import speiger.src.collections.PACKAGE.utils.ITERATORS;
 
 import speiger.src.collections.utils.HashUtil;
@@ -460,6 +463,41 @@ public class IMMUTABLE_HASH_SET KEY_GENERIC_TYPE extends ABSTRACT_SET KEY_GENERI
 		return new SetIterator(fromElement);
 	}
 	
+#if !TYPE_OBJECT
+	@Override
+	public KEY_TYPE[] TO_ARRAY(KEY_TYPE[] a) {
+		if(a == null || a.length < size()) a = new KEY_TYPE[size()];
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			a[i] = keys[index];
+		}
+		if (a.length > size) a[size] = EMPTY_KEY_VALUE;
+		return a;
+	}
+	
+#endif
+	@Override
+	@Deprecated
+	public Object[] toArray() {
+		if(isEmpty()) return ObjectArrays.EMPTY_ARRAY;
+		Object[] obj = new Object[size()];
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			obj[i] = KEY_TO_OBJ(keys[index]);
+		}
+		return obj;
+	}
+	
+	@Override
+	@Primitive
+	public <E> E[] toArray(E[] a) {
+		if(a == null) a = (E[])new Object[size()];
+		else if(a.length < size()) a = (E[])ObjectArrays.newArray(a.getClass().getComponentType(), size());
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			a[i] = (E)KEY_TO_OBJ(keys[index]);
+		}
+		if (a.length > size) a[size] = null;
+		return a;
+	}
+	
 	@Override
 	public IMMUTABLE_HASH_SET KEY_GENERIC_TYPE copy() {
 		IMMUTABLE_HASH_SET KEY_GENERIC_TYPE set = new IMMUTABLE_HASH_SETBRACES();

src/builder/resources/speiger/assets/collections/templates/sets/LinkedOpenCustomHashSet.template

@@ -28,6 +28,7 @@ import speiger.src.collections.objects.functions.consumer.BI_FROM_OBJECT_CONSUME
 #if !JDK_FUNCTION
 import speiger.src.collections.PACKAGE.functions.function.PREDICATE;
 #endif
+import speiger.src.collections.objects.utils.ObjectArrays;
 import speiger.src.collections.PACKAGE.functions.function.UNARY_OPERATOR;
 import speiger.src.collections.PACKAGE.utils.STRATEGY;
 import speiger.src.collections.utils.HashUtil;
@@ -528,6 +529,41 @@ public class LINKED_CUSTOM_HASH_SET KEY_GENERIC_TYPE extends CUSTOM_HASH_SET KEY
 		containsNull = false;
 	}
 	
+#if !TYPE_OBJECT
+	@Override
+	public KEY_TYPE[] TO_ARRAY(KEY_TYPE[] a) {
+		if(a == null || a.length < size()) a = new KEY_TYPE[size()];
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			a[i] = keys[index];
+		}
+		if (a.length > size) a[size] = EMPTY_KEY_VALUE;
+		return a;
+	}
+	
+#endif
+	@Override
+	@Deprecated
+	public Object[] toArray() {
+		if(isEmpty()) return ObjectArrays.EMPTY_ARRAY;
+		Object[] obj = new Object[size()];
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			obj[i] = KEY_TO_OBJ(keys[index]);
+		}
+		return obj;
+	}
+	
+	@Override
+	@Primitive
+	public <E> E[] toArray(E[] a) {
+		if(a == null) a = (E[])new Object[size()];
+		else if(a.length < size()) a = (E[])ObjectArrays.newArray(a.getClass().getComponentType(), size());
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			a[i] = (E)KEY_TO_OBJ(keys[index]);
+		}
+		if (a.length > size) a[size] = null;
+		return a;
+	}
+	
 	@Override
 	public void forEach(CONSUMER KEY_SUPER_GENERIC_TYPE action) {
 		Objects.requireNonNull(action);

src/builder/resources/speiger/assets/collections/templates/sets/LinkedOpenHashSet.template

@@ -31,6 +31,7 @@ import speiger.src.collections.PACKAGE.lists.LIST_ITERATOR;
 #if !TYPE_OBJECT
 import speiger.src.collections.PACKAGE.utils.ITERATORS;
 #endif
+import speiger.src.collections.objects.utils.ObjectArrays;
 import speiger.src.collections.utils.HashUtil;
 import speiger.src.collections.utils.SanityChecks;
 
@@ -383,6 +384,41 @@ public class LINKED_HASH_SET KEY_GENERIC_TYPE extends HASH_SET KEY_GENERIC_TYPE
 		return result;
 	}
 	
+#if !TYPE_OBJECT
+	@Override
+	public KEY_TYPE[] TO_ARRAY(KEY_TYPE[] a) {
+		if(a == null || a.length < size()) a = new KEY_TYPE[size()];
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			a[i] = keys[index];
+		}
+		if (a.length > size) a[size] = EMPTY_KEY_VALUE;
+		return a;
+	}
+	
+#endif
+	@Override
+	@Deprecated
+	public Object[] toArray() {
+		if(isEmpty()) return ObjectArrays.EMPTY_ARRAY;
+		Object[] obj = new Object[size()];
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			obj[i] = KEY_TO_OBJ(keys[index]);
+		}
+		return obj;
+	}
+	
+	@Override
+	@Primitive
+	public <E> E[] toArray(E[] a) {
+		if(a == null) a = (E[])new Object[size()];
+		else if(a.length < size()) a = (E[])ObjectArrays.newArray(a.getClass().getComponentType(), size());
+		for(int i = 0, index = firstIndex;index != -1;i++,index = (int)links[index]) {
+			a[i] = (E)KEY_TO_OBJ(keys[index]);
+		}
+		if (a.length > size) a[size] = null;
+		return a;
+	}
+	
 	@Override
 	public void forEach(CONSUMER KEY_SUPER_GENERIC_TYPE action) {
 		Objects.requireNonNull(action);

src/builder/resources/speiger/assets/collections/templates/sets/OpenCustomHashSet.template

@@ -27,6 +27,7 @@ import speiger.src.collections.PACKAGE.functions.function.PREDICATE;
 #endif
 import speiger.src.collections.PACKAGE.functions.function.UNARY_OPERATOR;
 import speiger.src.collections.PACKAGE.utils.STRATEGY;
+import speiger.src.collections.objects.utils.ObjectArrays;
 
 import speiger.src.collections.utils.HashUtil;
 import speiger.src.collections.utils.ITrimmable;
@@ -479,6 +480,41 @@ public class CUSTOM_HASH_SET KEY_GENERIC_TYPE extends ABSTRACT_SET KEY_GENERIC_T
 		return new SetIterator();
 	}
 	
+#if !TYPE_OBJECT
+	@Override
+	public KEY_TYPE[] TO_ARRAY(KEY_TYPE[] a) {
+		if(a == null || a.length < size()) a = new KEY_TYPE[size()];
+		for(int i = nullIndex-1, index = 0;i>=0;i--) {
+			if(!strategy.equals(keys[i], EMPTY_KEY_VALUE)) a[index++] = keys[i];
+		}
+		if (a.length > size) a[size] = EMPTY_KEY_VALUE;
+		return a;
+	}
+	
+#endif
+	@Override
+	@Deprecated
+	public Object[] toArray() {
+		if(isEmpty()) return ObjectArrays.EMPTY_ARRAY;
+		Object[] obj = new Object[size()];
+		for(int i = nullIndex-1, index = 0;i>=0;i--) {
+			if(!strategy.equals(keys[i], EMPTY_KEY_VALUE)) obj[index++] = KEY_TO_OBJ(keys[i]);
+		}
+		return obj;
+	}
+	
+	@Override
+	@Primitive
+	public <E> E[] toArray(E[] a) {
+		if(a == null) a = (E[])new Object[size()];
+		else if(a.length < size()) a = (E[])ObjectArrays.newArray(a.getClass().getComponentType(), size());
+		for(int i = nullIndex-1, index = 0;i>=0;i--) {
+			if(!strategy.equals(keys[i], EMPTY_KEY_VALUE)) a[index++] = (E)KEY_TO_OBJ(keys[i]);
+		}
+		if (a.length > size) a[size] = null;
+		return a;
+	}
+	
 	@Override
 	public CUSTOM_HASH_SET KEY_GENERIC_TYPE copy() {
 		CUSTOM_HASH_SET KEY_GENERIC_TYPE set = new CUSTOM_HASH_SETBRACES(0, loadFactor, strategy);

src/builder/resources/speiger/assets/collections/templates/sets/OpenHashSet.template

@@ -26,6 +26,8 @@ import speiger.src.collections.objects.functions.consumer.BI_FROM_OBJECT_CONSUME
 import speiger.src.collections.PACKAGE.functions.function.PREDICATE;
 #endif
 import speiger.src.collections.PACKAGE.functions.function.UNARY_OPERATOR;
+import speiger.src.collections.objects.utils.ObjectArrays;
+
 import speiger.src.collections.utils.HashUtil;
 import speiger.src.collections.utils.ITrimmable;
 import speiger.src.collections.utils.SanityChecks;
@@ -368,6 +370,41 @@ public class HASH_SET KEY_GENERIC_TYPE extends ABSTRACT_SET KEY_GENERIC_TYPE imp
 		containsNull = false;
 	}
 	
+#if !TYPE_OBJECT
+	@Override
+	public KEY_TYPE[] TO_ARRAY(KEY_TYPE[] a) {
+		if(a == null || a.length < size()) a = new KEY_TYPE[size()];
+		for(int i = nullIndex-1, index = 0;i>=0;i--) {
+			if(KEY_EQUALS_NOT_NULL(keys[i])) a[index++] = keys[i];
+		}
+		if (a.length > size) a[size] = EMPTY_KEY_VALUE;
+		return a;
+	}
+	
+#endif
+	@Override
+	@Deprecated
+	public Object[] toArray() {
+		if(isEmpty()) return ObjectArrays.EMPTY_ARRAY;
+		Object[] obj = new Object[size()];
+		for(int i = nullIndex-1, index = 0;i>=0;i--) {
+			if(KEY_EQUALS_NOT_NULL(keys[i])) obj[index++] = KEY_TO_OBJ(keys[i]);
+		}
+		return obj;
+	}
+	
+	@Override
+	@Primitive
+	public <E> E[] toArray(E[] a) {
+		if(a == null) a = (E[])new Object[size()];
+		else if(a.length < size()) a = (E[])ObjectArrays.newArray(a.getClass().getComponentType(), size());
+		for(int i = nullIndex-1, index = 0;i>=0;i--) {
+			if(KEY_EQUALS_NOT_NULL(keys[i])) a[index++] = (E)KEY_TO_OBJ(keys[i]);
+		}
+		if (a.length > size) a[size] = null;
+		return a;
+	}
+	
 	@Override
 	public void forEach(CONSUMER KEY_SUPER_GENERIC_TYPE action) {
 		if(size() <= 0) return;

src/main/java/speiger/src/collections/utils/Stack.java

@@ -1,5 +1,8 @@
 package speiger.src.collections.utils;
 
+import java.util.Collection;
+import java.util.NoSuchElementException;
+import java.util.function.IntFunction;
 
 /**
  * The Stack Interface represents the Last-In-First-Out layout (LIFO).
@@ -16,6 +19,14 @@ public interface Stack<T>
 	 */
 	public void push(T e);
 	
+	/**
+	 * Helper function that pushes the top element on top of the stack again.
+	 * @throws NoSuchElementException if the stack is empty
+	 */
+	public default void pushTop() {
+		push(top());
+	}
+	
 	/**
 	 * Removes the Object on top of the stack.
 	 * @return the element that is on top of the stack
@@ -59,4 +70,33 @@ public interface Stack<T>
  	 * @throws ArrayIndexOutOfBoundsException if the index is out of bounds
 	 */
 	public T peek(int index);
+	
+	/**
+	 * A method to drop the contents of the Queue without clearing the queue
+	 * @param <E> the keyType of elements maintained by this Collection
+	 * @return the contents of the queue into a seperate array.
+	 */
+	public default <E> E[] toArray() {
+		return toArray((E[])new Object[size()]); 
+	}
+	
+	/**
+	 * A method to drop the contents of the Stack without clearing the stack
+	 * @param array where the elements should be inserted to. If it does not fit then it creates a new appropriately created array
+	 * @param <E> the keyType of elements maintained by this Collection
+	 * @return the contents of the stack into a separate array.
+	 * @note if the Type is generic then a Object Array is created instead of a Type Array
+	 */
+	public <E> E[] toArray(E[] array);
+	
+	/**
+	 * A Helper function that simplifies the process of creating a new Array.
+	 * @param action the array creation function
+	 * @param <E> the returning arrayType
+	 * @return an array containing all of the elements in this collection
+	 * @see Collection#toArray(Object[])
+	 */
+	public default <E> E[] toArray(IntFunction<E[]> action) {
+		return toArray(action.apply(size()));
+	}
 }