Package org.moeaframework.util.tree

Class Node

java.lang.Object
org.moeaframework.util.tree.Node
All Implemented Interfaces:
Serializable, Named
Direct Known Subclasses:
Abs, Acos, Acosh, Add, And, Asin, Asinh, Atan, Atanh, Call, Ceil, Constant, Cos, Cosh, Define, Divide, Equals, Exp, Floor, For, Get, GreaterThan, GreaterThanOrEqual, IfElse, Lambda, LessThan, LessThanOrEqual, Log, Log10, Max, Min, Modulus, Multiply, NOP, Not, Or, Power, Round, Sequence, Set, Sign, Sin, Sinh, Square, SquareRoot, Subtract, Tan, Tanh, Truncate, While
public abstract class Node extends Object implements Serializable, Named
A node in an expression tree. Expression trees are strongly typed, meaning nodes have defined return types and argument types. The return type of all nodes must match the argument type from its parent node.
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    Node()
    Constructs a new node.
    Node(Class<?> returnType, Class<?>... argumentTypes)
    Constructs a new node with the given return type and argument types.

  • Method Summary

    Modifier and Type
    Method
    Description
    abstract Node
    copyNode()
    Returns a copy of this node, but without any children or parents assigned.
    Node
    copyTree()
    Returns a copy of this node including copies of all its arguments (child nodes).
    abstract Object
    evaluate(Environment environment)
    Evaluates this node in the context of the specified environment.
    Node
    getArgument(int index)
    Returns the argument (child node) at the specified index.
    Class<?>
    getArgumentType(int index)
    Returns the type of the argument (child node) at the specified index.
    int
    getDepth()
    Returns the depth of this node, which is the number of branches between this node and the root.
    Node
    getFunctionAt(int index)
    Returns the function (non-terminal) node at the specified index in the subtree rooted at this node.
    Node
    getFunctionAt(Class<?> type, int index)
    Returns the function (non-terminal) node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type.
    int
    getMaximumHeight()
    Returns the number of branches between this node and the furthest leaf.
    int
    getMinimumHeight()
    Returns the number of branches between this node and the nearest leaf.
    String
    getName()
    Returns the name of this object.
    Node
    getNodeAt(int index)
    Returns the node at the specified index in the subtree rooted at this node.
    protected Node
    getNodeAt(Class<?> type, boolean includeFunctions, boolean includeTerminals, int index)
    Returns the node at the specified index in the subtree rooted at this node.
    Node
    getNodeAt(Class<?> type, int index)
    Returns the node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type.
    int
    getNumberOfArguments()
    Returns the number of arguments (child nodes) of this node.
    int
    getNumberOfFunctions()
    Returns the number of function (non-terminal) nodes contained in the subtree rooted at this node.
    int
    getNumberOfFunctions(Class<?> type)
    Returns the number of function (non-terminal) nodes contained in the subtree rooted at this node that match the given return type.
    int
    getNumberOfNodes()
    Returns the number of nodes contained in the subtree rooted at this node.
    int
    getNumberOfNodes(Class<?> type)
    Returns the number of nodes contained in the subtree rooted at this node that match the given return type.
    protected int
    getNumberOfNodes(Class<?> type, boolean includeFunctions, boolean includeTerminals)
    Returns the number of nodes contained in the subtree rooted at this node.
    int
    getNumberOfTerminals()
    Returns the number of terminal nodes contained in the subtree rooted at this node.
    int
    getNumberOfTerminals(Class<?> type)
    Returns the number of terminal nodes contained in the subtree rooted at this node that match the given return type.
    Node
    getParent()
    Returns the parent of this node; or null if this node has no parent.
    Class<?>
    getReturnType()
    Returns the return type of this node.
    Node
    getTerminalAt(int index)
    Returns the terminal node at the specified index in the subtree rooted at this node.
    Node
    getTerminalAt(Class<?> type, int index)
    Returns the terminal node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type.
    boolean
    isFixed()
    Returns true if this node should not be modified, altered, or replaced; false otherwise.
    boolean
    isTerminal()
    Returns true if this is a terminal node (has no arguments); false otherwise.
    boolean
    isValid()
    Returns true if this node and its arguments are valid; false otherwise.
    Node
    setArgument(int index, Node expression)
    Sets the argument (child node) at the specified index.
    void
    setFixed(boolean fixed)
    Set to true if this node should not be modified, altered, or replaced; false otherwise.
    void
    setFixedTree(boolean fixed)
    Calls setFixed(boolean) on all nodes in the subtree rooted at this node.
    int
    size()
    Returns the number of nodes contained in the tree rooted at this node.
    String
    toString()
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • Node

      public Node()
      Constructs a new node.

    • Node

      public Node(Class<?> returnType, Class<?>... argumentTypes)
      Constructs a new node with the given return type and argument types.
      Parameters:
      returnType - the return type of the node
      argumentTypes - the type of the arguments, if any, for the node

  • Method Details

    • getName

      public String getName()
      Description copied from interface: Named
      Returns the name of this object. The format for the name depends on the specific implementation, but in general we recommend:
      1. Prefer using alphanumeric characters including '_' and '-'.
      2. Avoid whitespace and other control characters.
      3. null can be returned, if allowed by the implementation, to indicate the object is anonymous or has no assigned name.
      Specified by:
      getName in interface Named
      Returns:
      the name

    • setFixedTree

      public void setFixedTree(boolean fixed)
      Calls setFixed(boolean) on all nodes in the subtree rooted at this node.
      Parameters:
      fixed - true if all nodes in the subtree rooted at this node should not be modified, altered, or replaced; false otherwise

    • setFixed

      public void setFixed(boolean fixed)
      Set to true if this node should not be modified, altered, or replaced; false otherwise.
      Parameters:
      fixed - true if this node should not be modified, altered, or replaced; false otherwise

    • isFixed

      public boolean isFixed()
      Returns true if this node should not be modified, altered, or replaced; false otherwise.
      Returns:
      true if this node should not be modified, altered, or replaced; false otherwise

    • getNumberOfArguments

      public int getNumberOfArguments()
      Returns the number of arguments (child nodes) of this node.
      Returns:
      the number of arguments (child nodes) of this node

    • getArgument

      public Node getArgument(int index)
      Returns the argument (child node) at the specified index.
      Parameters:
      index - the index of the argument to return
      Returns:
      the argument (child node) at the specified index

    • getParent

      public Node getParent()
      Returns the parent of this node; or null if this node has no parent.
      Returns:
      the parent of this node; or null if this node has no parent

    • getReturnType

      public Class<?> getReturnType()
      Returns the return type of this node.
      Returns:
      the return type of this node

    • getArgumentType

      public Class<?> getArgumentType(int index)
      Returns the type of the argument (child node) at the specified index.
      Parameters:
      index - the index of the argument
      Returns:
      the type of the argument (child node) at the specified index

    • setArgument

      public Node setArgument(int index, Node expression)
      Sets the argument (child node) at the specified index.
      Parameters:
      index - the index of the new argument
      expression - the expression defining the argument
      Returns:
      a reference to this node, allowing multiple calls to be chained together

    • size

      public int size()
      Returns the number of nodes contained in the tree rooted at this node.
      Returns:
      the number of nodes contained in the tree rooted at this node

    • getDepth

      public int getDepth()
      Returns the depth of this node, which is the number of branches between this node and the root.
      Returns:
      the depth of this node

    • getMinimumHeight

      public int getMinimumHeight()
      Returns the number of branches between this node and the nearest leaf.
      Returns:
      the number of branches between this node and the nearest leaf

    • getMaximumHeight

      public int getMaximumHeight()
      Returns the number of branches between this node and the furthest leaf.
      Returns:
      the number of branches between this node and the furthest leaf

    • copyNode

      public abstract Node copyNode()
      Returns a copy of this node, but without any children or parents assigned.
      Returns:
      a copy of this node, but without any children or parents assigned

    • copyTree

      public Node copyTree()
      Returns a copy of this node including copies of all its arguments (child nodes). All attributes of the node are also retained, such as isFixed().
      Returns:
      a copy of this node including copies of all its arguments (child nodes)

    • evaluate

      public abstract Object evaluate(Environment environment)
      Evaluates this node in the context of the specified environment.
      Parameters:
      environment - the execution environment
      Returns:
      the result of evaluating this node

    • isValid

      public boolean isValid()
      Returns true if this node and its arguments are valid; false otherwise. A valid node has all arguments defined, all arguments are valid, and all arguments are the appropriate type.
      Returns:
      true if this node and its arguments are valid; false otherwise

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • isTerminal

      public boolean isTerminal()
      Returns true if this is a terminal node (has no arguments); false otherwise.
      Returns:
      true if this is a terminal node (has no arguments); false otherwise

    • getNumberOfFunctions

      public int getNumberOfFunctions(Class<?> type)
      Returns the number of function (non-terminal) nodes contained in the subtree rooted at this node that match the given return type.
      Parameters:
      type - the return type of the node
      Returns:
      the number of function (non-terminal) nodes contained in the subtree rooted at this node that match the given return type

    • getFunctionAt

      public Node getFunctionAt(Class<?> type, int index)
      Returns the function (non-terminal) node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type. A depth-first search (DFS) walk of the tree is used to find the appropriate node.
      Parameters:
      type - the return type of the node
      index - the index of the node to return
      Returns:
      the function (non-terminal) node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type
      Throws:
      IndexOutOfBoundsException - if the index refers to a node not within the subtree rooted at this node

    • getNumberOfFunctions

      public int getNumberOfFunctions()
      Returns the number of function (non-terminal) nodes contained in the subtree rooted at this node.
      Returns:
      the number of function (non-terminal) nodes contained in the subtree rooted at this node

    • getFunctionAt

      public Node getFunctionAt(int index)
      Returns the function (non-terminal) node at the specified index in the subtree rooted at this node. A depth-first search (DFS) walk of the tree is used to find the appropriate node.
      Parameters:
      index - the index of the node to return
      Returns:
      the function (non-terminal) node at the specified index in the subtree rooted at this node
      Throws:
      IndexOutOfBoundsException - if the index refers to a node not within the subtree rooted at this node

    • getNumberOfTerminals

      public int getNumberOfTerminals(Class<?> type)
      Returns the number of terminal nodes contained in the subtree rooted at this node that match the given return type.
      Parameters:
      type - the return type of the node
      Returns:
      the number of terminal nodes contained in the subtree rooted at this node that match the given return type

    • getTerminalAt

      public Node getTerminalAt(Class<?> type, int index)
      Returns the terminal node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type. A depth-first search (DFS) walk of the tree is used to find the appropriate node.
      Parameters:
      type - the return type of the node
      index - the index of the node to return
      Returns:
      the terminal node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type
      Throws:
      IndexOutOfBoundsException - if the index refers to a node not within the subtree rooted at this node

    • getNumberOfTerminals

      public int getNumberOfTerminals()
      Returns the number of terminal nodes contained in the subtree rooted at this node.
      Returns:
      the number of terminal nodes contained in the subtree rooted at this node

    • getTerminalAt

      public Node getTerminalAt(int index)
      Returns the terminal node at the specified index in the subtree rooted at this node. A depth-first search (DFS) walk of the tree is used to find the appropriate node.
      Parameters:
      index - the index of the node to return
      Returns:
      the terminal node at the specified index in the subtree rooted at this node
      Throws:
      IndexOutOfBoundsException - if the index refers to a node not within the subtree rooted at this node

    • getNumberOfNodes

      public int getNumberOfNodes(Class<?> type)
      Returns the number of nodes contained in the subtree rooted at this node that match the given return type.
      Parameters:
      type - the return type of the node
      Returns:
      the number of nodes contained in the subtree rooted at this node that match the given return type

    • getNodeAt

      public Node getNodeAt(Class<?> type, int index)
      Returns the node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type. A depth-first search (DFS) walk of the tree is used to find the appropriate node.
      Parameters:
      type - the return type of the node
      index - the index of the node to return
      Returns:
      the node at the specified index in the subtree rooted at this node, counting only nodes that match the given return type
      Throws:
      IndexOutOfBoundsException - if the index refers to a node not within the subtree rooted at this node

    • getNumberOfNodes

      public int getNumberOfNodes()
      Returns the number of nodes contained in the subtree rooted at this node.
      Returns:
      the number of nodes contained in the subtree rooted at this node

    • getNodeAt

      public Node getNodeAt(int index)
      Returns the node at the specified index in the subtree rooted at this node. A depth-first search (DFS) walk of the tree is used to find the appropriate node.
      Parameters:
      index - the index of the node to return
      Returns:
      the node at the specified index in the subtree rooted at this node
      Throws:
      IndexOutOfBoundsException - if the index refers to a node not within the subtree rooted at this node

    • getNumberOfNodes

      protected int getNumberOfNodes(Class<?> type, boolean includeFunctions, boolean includeTerminals)
      Returns the number of nodes contained in the subtree rooted at this node.
      Parameters:
      type - the return type of the node
      includeFunctions - true if functions (non-terminals) are counted; false otherwise
      includeTerminals - true if terminals are counted; false otherwise
      Returns:
      the number of nodes contained in the subtree rooted at this node

    • getNodeAt

      protected Node getNodeAt(Class<?> type, boolean includeFunctions, boolean includeTerminals, int index)
      Returns the node at the specified index in the subtree rooted at this node. A depth-first search (DFS) walk of the tree is used to find the appropriate node.
      Parameters:
      type - the return type of the node
      includeFunctions - true if functions (non-terminals) are counted; false otherwise
      includeTerminals - true if terminals are counted; false otherwise
      index - the index of the node to return
      Returns:
      the node at the specified index in the subtree rooted at this node
      Throws:
      IndexOutOfBoundsException - if the index refers to a node not within the subtree rooted at this node