Package com.igormaznitsa.jcp.expression

Class ExpressionTreeElement

java.lang.Object
com.igormaznitsa.jcp.expression.ExpressionTreeElement
public class ExpressionTreeElement extends Object
The class describes a wrapper around an expression item to be saved into an expression tree

  • Field Details

    • OPERATOR_SUB

      private static final OperatorSUB OPERATOR_SUB
      Inside constant to be used for speed up some operations

    • EMPTY_SLOT

      public static final ExpressionTreeElement EMPTY_SLOT

    • EMPTY

      private static final ExpressionTreeElement[] EMPTY
      Empty array to avoid unnecessary operations

    • savedItem

      private ExpressionItem savedItem
      The variable contains the wrapped expression item

    • childElements

      private ExpressionTreeElement[] childElements
      The array contains links to the tree element children

    • parentTreeElement

      private ExpressionTreeElement parentTreeElement
      The link to the parent element, if it is the tree root then it contains null

    • priority

      private int priority
      The priority of the tree element, it is very strongly used during tree sorting

    • nextChildSlot

      private int nextChildSlot
      Because I fill children sequentially, the variable contains the index of the first empty child slot

    • sourceString

      private final String sourceString
      Contains the source string for the expression.

    • includeStack

      private final FilePositionInfo[] includeStack
      Current include stack of the preprocessor to the source string.

  • Constructor Details

    • ExpressionTreeElement

      private ExpressionTreeElement()

    • ExpressionTreeElement

      ExpressionTreeElement(ExpressionItem item, @MustNotContainNull FilePositionInfo[] callStack, String sourceString)
      The constructor
      Parameters:
      item - an expression item to be wrapped
      callStack - current call stack
      sourceString - source string for the expression

  • Method Details

    • isEmptySlot

      public boolean isEmptySlot()
      Allows to check that the element is EMPTY_SLOT
      Returns:
      true if the element is empty slot, false otherwise

    • assertNotEmptySlot

      private void assertNotEmptySlot()

    • makeMaxPriority

      void makeMaxPriority()
      Inside auxiliary function to set the maximum priority the the element

    • getItem

      public ExpressionItem getItem()
      Get the wrapped item
      Returns:
      the item to be wrapped by the object

    • getArity

      public int getArity()
      Get arity for the element (I mean possible children number)
      Returns:
      the arity, zero for elements without children

    • getParent

      public ExpressionTreeElement getParent()
      Get the parent for the element
      Returns:
      the parent for the element or null if the element is the tree root

    • getPriority

      public int getPriority()
      Get the current priority of the element
      Returns:
      the priority

    • addSubTree

      public ExpressionTreeElement addSubTree(ExpressionTree tree)
      Add a tree as new child and make the maximum priority for it
      Parameters:
      tree - a tree to be added as a child, must not be null
      Returns:
      it returns this

    • replaceElement

      public boolean replaceElement(ExpressionTreeElement oldOne, ExpressionTreeElement newOne)
      It replaces a child element
      Parameters:
      oldOne - the old expression element to be replaced (must not be null)
      newOne - the new expression element to be used instead the old one (must not be null)
      Returns:
      true if the element was found and replaced, else false

    • getChildForIndex

      public ExpressionTreeElement getChildForIndex(int index)
      Get the child element for its index (the first is 0)
      Parameters:
      index - the index of the needed child
      Returns:
      the child or EMPTY_SLOT
      Throws:
      ArrayIndexOutOfBoundsException - it will be thrown if an impossible index is being used
      See Also:

    • addTreeElement

      public ExpressionTreeElement addTreeElement(ExpressionTreeElement element)
      Add tree element with sorting operation depends on priority of the elements
      Parameters:
      element - the element to be added, must not be null
      Returns:
      the element which should be used as the last for the current tree

    • isFull

      public boolean isFull()
      It allows to check that all children slots have been filled
      Returns:
      true if there is not any free child slot else false

    • fillArguments

      public void fillArguments(@MustNotContainNull List<ExpressionTree> arguments)
      It fills children slots from a list containing expression trees
      Parameters:
      arguments - the list containing trees to be used as children

    • addElementToNextFreeSlot

      private void addElementToNextFreeSlot(ExpressionTreeElement element)
      Add an expression element into the next free child slot
      Parameters:
      element - an element to be added, must not be null

    • postProcess

      public void postProcess()
      Post-processing after the tree is formed, the unary minus operation will be optimized