Module io.jenetics.ext
Package io.jenetics.ext.rewriting

Class TreeRewriteRule<V>

java.lang.Object
io.jenetics.ext.rewriting.TreeRewriteRule<V>
All Implemented Interfaces:
TreeRewriter<V>, Serializable
public final class TreeRewriteRule<V> extends Object implements TreeRewriter<V>, Serializable
Represents a tree rewrite rule. A rewrite rule consists of a match pattern, which must be matched, and a substitution pattern, which is expanded and replaces the variables in the pattern. Some simple arithmetic rewrite rules. 
 
     add($x,0) -> $x
     mul($x,1) -> $x
The substitution pattern may only use variables, already defined in the match pattern. So, the creation of the following rewrite rule s would lead to an IllegalArgumentException: 
 
     add($x,0) -> $y
     mul(0,1) -> mul($x,1)
Since:
5.0
Version:
5.0
See Also:

  • Constructor Details

    • TreeRewriteRule

      public TreeRewriteRule(TreePattern<V> left, TreePattern<V> right)
      Create a new rewrite rule from the given matching (left) and replacement (right) pattern.
      Parameters:
      left - the matching pattern of the rule
      right - the substitution pattern
      Throws:
      NullPointerException - if one of the arguments is null
      IllegalArgumentException - if the template pattern uses variables not defined in the matcher pattern

  • Method Details

    • left

      public TreePattern<V> left()
      Return the rule matching pattern.
      Returns:
      the rule matching pattern

    • right

      public TreePattern<V> right()
      Return the replacement pattern of the rule.
      Returns:
      the replacement pattern of the rule

    • map

      public <B> TreeRewriteRule<B> map(Function<? super V,? extends B> mapper)
      Maps this rewrite rule from type V to type B.
      Type Parameters:
      B - the target type
      Parameters:
      mapper - the type mapper
      Returns:
      a new rewrite rule for the mapped type
      Throws:
      NullPointerException - if the mapper is null

    • rewrite

      public int rewrite(TreeNode<V> tree, int limit)
      Description copied from interface: TreeRewriter
      Applies the rewriting to the given (mutable) tree. The tree rewrite is done in place. Via the limit parameter, the termination of the tree-rewrite process can be guaranteed.
      Specified by:
      rewrite in interface TreeRewriter<V>
      Parameters:
      tree - the tree to be rewritten
      limit - the maximal number this rewrite rule is applied to the given tree. This guarantees the termination of the rewrite method.
      Returns:
      the number of rewrites applied to the input tree

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • parse

      public static <V> TreeRewriteRule<V> parse(String rule, Function<? super String,? extends V> mapper)
      Compiles the string representation of a rewrite rule: 
       
     add($x,0) -> $x
     mul($x,1) -> $x
      Type Parameters:
      V - the tree node type
      Parameters:
      rule - the rewrite rule
      mapper - the mapper function which converts the node value into the actual type V
      Returns:
      a new rewrite rule, compiled from the given rule string
      Throws:
      IllegalArgumentException - if the rewrite rule is invalid
      NullPointerException - if on of the arguments is null

    • parse

      public static TreeRewriteRule<String> parse(String rule)
      Compiles the string representation of a rewrite rule: 
       
     add($x,0) -> $x
     mul($x,1) -> $x
      Parameters:
      rule - the rewrite rule
      Returns:
      a new rewrite rule, compiled from the given rule string
      Throws:
      IllegalArgumentException - if the rewrite rule is invalid
      NullPointerException - if on of the arguments is null