Package org.parboiled.support

Class DefaultValueStack<V>

  • Type Parameters:
    V - the type of the value objects
    All Implemented Interfaces:
    Iterable<V>, ValueStack<V>
    Direct Known Subclasses:
    DebuggingValueStack
    public class DefaultValueStack<V>
extends Object
implements ValueStack<V>
    An implementation of a stack of value objects providing an efficient snapshot capability and a number of convenience methods. The current state of the stack can be saved and restored in small constant time with the methods takeSnapshot() and restoreSnapshot(Object) ()}. The implementation also serves as an Iterable over the current stack values (the values are being provided with the last value (on top of the stack) first).

    • Constructor Summary

      Constructors 
      Constructor Description
      DefaultValueStack()
      Initializes an empty value stack.
      DefaultValueStack​(Iterable<V> values)
      Initializes a value stack containing the given values with the last value being at the top of the stack.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void clear()
      Clears all values.
      void dup()
      Duplicates the top value.
      boolean isEmpty()
      Determines whether the stack is empty.
      Iterator<V> iterator()  
      V peek()
      Returns the value at the top of the stack without removing it.
      V peek​(int down)
      Returns the value the given number of elements below the top of the stack without removing it.
      void poke​(int down, V value)
      Replaces the element the given number of elements below the current top of the stack.
      void poke​(V value)
      Replaces the current top value with the given value.
      V pop()
      Removes the value at the top of the stack and returns it.
      V pop​(int down)
      Removes the value the given number of elements below the top of the stack.
      void push​(int down, V value)
      Inserts the given value a given number of elements below the current top of the stack.
      void push​(V value)
      Pushes the given value onto the stack.
      void pushAll​(Iterable<V> values)
      Pushes all given elements onto the stack (in the order as given).
      void pushAll​(V firstValue, V... moreValues)
      Pushes all given elements onto the stack (in the order as given).
      void restoreSnapshot​(Object snapshot)
      Restores the stack state as previously returned by ValueStack.takeSnapshot().
      int size()
      Returns the number of elements currently on the stack.
      void swap()
      Swaps the top two stack values.
      void swap3()
      Reverses the order of the top 3 stack values.
      void swap4()
      Reverses the order of the top 4 stack values.
      void swap5()
      Reverses the order of the top 5 stack values.
      void swap6()
      Reverses the order of the top 5 stack values.
      Object takeSnapshot()
      Returns an object representing the current state of the stack.

    • Constructor Detail

      • DefaultValueStack

        public DefaultValueStack()
        Initializes an empty value stack.

      • DefaultValueStack

        public DefaultValueStack​(Iterable<V> values)
        Initializes a value stack containing the given values with the last value being at the top of the stack.
        Parameters:
        values - the initial stack values

    • Method Detail

      • isEmpty

        public boolean isEmpty()
        Description copied from interface: ValueStack
        Determines whether the stack is empty.
        Specified by:
        isEmpty in interface ValueStack<V>
        Returns:
        true if empty

      • size

        public int size()
        Description copied from interface: ValueStack
        Returns the number of elements currently on the stack.
        Specified by:
        size in interface ValueStack<V>
        Returns:
        the number of elements

      • clear

        public void clear()
        Description copied from interface: ValueStack
        Clears all values.
        Specified by:
        clear in interface ValueStack<V>

      • takeSnapshot

        public Object takeSnapshot()
        Description copied from interface: ValueStack
        Returns an object representing the current state of the stack. This cost of running this operation is negligible and independent from the size of the stack.
        Specified by:
        takeSnapshot in interface ValueStack<V>
        Returns:
        an object representing the current state of the stack

      • push

        public void push​(V value)
        Description copied from interface: ValueStack
        Pushes the given value onto the stack. Equivalent to push(0, value).
        Specified by:
        push in interface ValueStack<V>
        Parameters:
        value - the value

      • push

        public void push​(int down,
                 V value)
        Description copied from interface: ValueStack
        Inserts the given value a given number of elements below the current top of the stack.
        Specified by:
        push in interface ValueStack<V>
        Parameters:
        down - the number of elements to skip before inserting the value (0 being equivalent to push(value))
        value - the value

      • pushAll

        public void pushAll​(V firstValue,
                    V... moreValues)
        Description copied from interface: ValueStack
        Pushes all given elements onto the stack (in the order as given).
        Specified by:
        pushAll in interface ValueStack<V>
        Parameters:
        firstValue - the first value
        moreValues - the other values

      • pushAll

        public void pushAll​(Iterable<V> values)
        Description copied from interface: ValueStack
        Pushes all given elements onto the stack (in the order as given).
        Specified by:
        pushAll in interface ValueStack<V>
        Parameters:
        values - the values

      • pop

        public V pop()
        Description copied from interface: ValueStack
        Removes the value at the top of the stack and returns it.
        Specified by:
        pop in interface ValueStack<V>
        Returns:
        the current top value

      • pop

        public V pop​(int down)
        Description copied from interface: ValueStack
        Removes the value the given number of elements below the top of the stack.
        Specified by:
        pop in interface ValueStack<V>
        Parameters:
        down - the number of elements to skip before removing the value (0 being equivalent to pop())
        Returns:
        the value

      • peek

        public V peek()
        Description copied from interface: ValueStack
        Returns the value at the top of the stack without removing it.
        Specified by:
        peek in interface ValueStack<V>
        Returns:
        the current top value

      • peek

        public V peek​(int down)
        Description copied from interface: ValueStack
        Returns the value the given number of elements below the top of the stack without removing it.
        Specified by:
        peek in interface ValueStack<V>
        Parameters:
        down - the number of elements to skip (0 being equivalent to peek())
        Returns:
        the value

      • poke

        public void poke​(V value)
        Description copied from interface: ValueStack
        Replaces the current top value with the given value. Equivalent to poke(0, value).
        Specified by:
        poke in interface ValueStack<V>
        Parameters:
        value - the value

      • poke

        public void poke​(int down,
                 V value)
        Description copied from interface: ValueStack
        Replaces the element the given number of elements below the current top of the stack.
        Specified by:
        poke in interface ValueStack<V>
        Parameters:
        down - the number of elements to skip before replacing the value (0 being equivalent to poke(value))
        value - the value to replace with

      • dup

        public void dup()
        Description copied from interface: ValueStack
        Duplicates the top value. Equivalent to push(peek()).
        Specified by:
        dup in interface ValueStack<V>

      • swap

        public void swap()
        Description copied from interface: ValueStack
        Swaps the top two stack values.
        Specified by:
        swap in interface ValueStack<V>

      • swap3

        public void swap3()
        Description copied from interface: ValueStack
        Reverses the order of the top 3 stack values.
        Specified by:
        swap3 in interface ValueStack<V>

      • swap4

        public void swap4()
        Description copied from interface: ValueStack
        Reverses the order of the top 4 stack values.
        Specified by:
        swap4 in interface ValueStack<V>

      • swap5

        public void swap5()
        Description copied from interface: ValueStack
        Reverses the order of the top 5 stack values.
        Specified by:
        swap5 in interface ValueStack<V>

      • swap6

        public void swap6()
        Description copied from interface: ValueStack
        Reverses the order of the top 5 stack values.
        Specified by:
        swap6 in interface ValueStack<V>