Package jflex

Class Action

java.lang.Object
jflex.Action
public final class Action extends Object
Encapsulates an action in the specification.

It stores the Java code as String together with a priority (line number in the specification).

Version:
JFlex 1.7.0

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    BACKWARD_ACTION
    Action of the backward pass for lookahead
    (package private) String
    content
    The Java code this Action represents
    private int
    entryState
    The entry state of the corresponding forward DFA (if general lookahead)
    static final int
    FINITE_CHOICE
    Action of a lookahead expression r1/r2 with a finite choice of fixed lengths in r2
    static final int
    FIXED_BASE
    Action of a lookahead expression r1/r2 with fixed length r1
    static final int
    FIXED_LOOK
    Action of a lookahead expression r1/r2 with fixed length r2
    static final int
    FORWARD_ACTION
    Action of the 2nd forward pass for lookahead
    static final int
    GENERAL_LOOK
    Action of a general lookahead expression
    private int
    kind
    Which kind of action this is.
    private int
    len
    The length of the lookahead (if fixed)
    static final int
    NORMAL
    A normal action
    (package private) int
    priority
    The priority (i.e.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Action(int kind)
    Creates a new Action object of the specified kind.
    Action(String content, int priority)
    Creates a new Action object with specified content and line number.

  • Method Summary

    Modifier and Type
    Method
    Description
    Action
    copyChoice(int length)
    copyChoice.
    boolean
    equals(Object o)
    int
    getEntryState()
    Return the corresponding entry state for the forward DFA (if this is a general lookahead expression)
    Action
    getHigherPriority(Action other)
    Compares the priority value of this Action with the specified action.
    int
    getLookLength()
    The length of the lookahead or base if this is a fixed length lookahead action.
    int
    hashCode()
    Calculate hash value.
    boolean
    isEmittable()
    Return true if code for this is action should be emitted, false if it is a BACK/FORWARD lookahead action.
    boolean
    isEquiv(Action a)
    Returns true iff the parameter is an Action with the same content as this one.
    boolean
    isGenLookAction()
    Return true iff this is action belongs to a general lookahead rule.
    int
    lookAhead()
    Return kind of lookahead.
    String
    lookString()
    String representation of the lookahead kind of this action.
    void
    setEntryState(int entryState)
    Set the corresponding entry state for the forward DFA of this action (if this is a general lookahead expression)
    void
    setLookAction(int kind, int data)
    Sets the lookahead kind and data for this action
    String
    toString()
    Returns the String representation of this object.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • NORMAL

      public static final int NORMAL
      A normal action
      See Also:

    • FIXED_BASE

      public static final int FIXED_BASE
      Action of a lookahead expression r1/r2 with fixed length r1
      See Also:

    • FIXED_LOOK

      public static final int FIXED_LOOK
      Action of a lookahead expression r1/r2 with fixed length r2
      See Also:

    • FINITE_CHOICE

      public static final int FINITE_CHOICE
      Action of a lookahead expression r1/r2 with a finite choice of fixed lengths in r2
      See Also:

    • GENERAL_LOOK

      public static final int GENERAL_LOOK
      Action of a general lookahead expression
      See Also:

    • FORWARD_ACTION

      public static final int FORWARD_ACTION
      Action of the 2nd forward pass for lookahead
      See Also:

    • BACKWARD_ACTION

      public static final int BACKWARD_ACTION
      Action of the backward pass for lookahead
      See Also:

    • content

      String content
      The Java code this Action represents

    • priority

      int priority
      The priority (i.e. line number in the specification) of this Action.

    • kind

      private int kind
      Which kind of action this is. (normal, a/b with fixed length a, fixed length b, etc)

    • len

      private int len
      The length of the lookahead (if fixed)

    • entryState

      private int entryState
      The entry state of the corresponding forward DFA (if general lookahead)

  • Constructor Details

    • Action

      public Action(String content, int priority)
      Creates a new Action object with specified content and line number.
      Parameters:
      content - java code
      priority - line number

    • Action

      public Action(int kind)
      Creates a new Action object of the specified kind. Only accepts FORWARD_ACTION or BACKWARD_ACTION.
      Parameters:
      kind - the kind of action
      See Also:

  • Method Details

    • getHigherPriority

      public Action getHigherPriority(Action other)
      Compares the priority value of this Action with the specified action.
      Parameters:
      other - the other Action to compare this Action with.
      Returns:
      this Action if it has higher priority - the specified one, if not.

    • toString

      public String toString()
      Returns the String representation of this object.
      Overrides:
      toString in class Object
      Returns:
      string representation of the action

    • isEquiv

      public boolean isEquiv(Action a)
      Returns true iff the parameter is an Action with the same content as this one.
      Parameters:
      a - the object to compare this Action with
      Returns:
      true if the action strings are equal

    • hashCode

      public int hashCode()
      Calculate hash value.
      Overrides:
      hashCode in class Object
      Returns:
      a hash value for this Action

    • equals

      public boolean equals(Object o)

      Test for equality to another object.

      This action equals another object if the other object is an equivalent action.

      Overrides:
      equals in class Object
      See Also:

    • isGenLookAction

      public boolean isGenLookAction()
      Return true iff this is action belongs to a general lookahead rule.
      Returns:
      true if this actions belongs to a general lookahead rule.

    • isEmittable

      public boolean isEmittable()
      Return true if code for this is action should be emitted, false if it is a BACK/FORWARD lookahead action.
      Returns:
      true if code should be emitted for this action.

    • lookAhead

      public int lookAhead()
      Return kind of lookahead.
      Returns:
      a int.

    • setLookAction

      public void setLookAction(int kind, int data)
      Sets the lookahead kind and data for this action
      Parameters:
      kind - which kind of lookahead it is
      data - the length for fixed length lookaheads.

    • getLookLength

      public int getLookLength()
      The length of the lookahead or base if this is a fixed length lookahead action.
      Returns:
      a int.

    • getEntryState

      public int getEntryState()
      Return the corresponding entry state for the forward DFA (if this is a general lookahead expression)
      Returns:
      the forward DFA entry state (+1 is the backward DFA)

    • setEntryState

      public void setEntryState(int entryState)
      Set the corresponding entry state for the forward DFA of this action (if this is a general lookahead expression)
      Parameters:
      entryState - a int.

    • copyChoice

      public Action copyChoice(int length)
      copyChoice.
      Parameters:
      length - a int.
      Returns:
      a Action object.

    • lookString

      public String lookString()
      String representation of the lookahead kind of this action.
      Returns:
      the string representation