Package org.apache.cayenne.exp.parser

Class SimpleNode

java.lang.Object
org.apache.cayenne.exp.Expression
org.apache.cayenne.exp.parser.SimpleNode
All Implemented Interfaces:
Serializable, Node, XMLSerializable
Direct Known Subclasses:
AggregateConditionNode, ASTAsterisk, ASTCustomOperator, ASTEnclosingObject, ASTFullObject, ASTList, ASTNegate, ASTPath, ASTScalar, ASTSubquery, ConditionNode, EvaluatedNode
public abstract class SimpleNode extends Expression implements Node
Superclass of AST* expressions that implements Node interface defined by JavaCC framework.

Some parts of the parser are based on OGNL parser, copyright (c) 2002, Drew Davidson and Luke Blanshard.

Since:
1.1
See Also:

  • Field Details

    • parent

      protected Node parent

    • children

      protected Node[] children

    • id

      protected int id

  • Constructor Details

    • SimpleNode

      protected SimpleNode(int i)

  • Method Details

    • encodeScalarAsEJBQL

      protected static void encodeScalarAsEJBQL(List<Object> parameterAccumulator, Appendable out, Object scalar) throws IOException

      This is a utility method that can represent the supplied scalar as either an EJBQL literal into the supplied PrintWriter or is able to add the scalar to the parameters and to instead write a positional parameter to the EJBQL written to the PrintWriter. If the parameters are null and the scalar object is not able to be represented as an EJBQL literal then the method will throw a runtime exception to indicate that it has failed to produce valid EJBQL.

      Throws:
      IOException

    • appendScalarAsString

      protected static void appendScalarAsString(Appendable out, Object scalar, char quoteChar) throws IOException
      Utility method that encodes an object that is not an expression Node to String.
      Throws:
      IOException

    • appendAsEscapedString

      protected static void appendAsEscapedString(Appendable out, String source) throws IOException
      Utility method that prints a string to the provided Appendable, escaping special characters.
      Throws:
      IOException

    • getPathAliases

      public Map<String,String> getPathAliases()
      Always returns empty map.
      Specified by:
      getPathAliases in class Expression
      Since:
      3.0

    • getExpressionOperator

      protected abstract String getExpressionOperator(int index)

    • getEJBQLExpressionOperator

      protected String getEJBQLExpressionOperator(int index)
      Returns operator for EJBQL statements, which can differ for Cayenne expression operator

    • pruneNodeForPrunedChild

      protected boolean pruneNodeForPrunedChild(Object prunedChild)
      Description copied from class: Expression
      Returns true if this node should be pruned from expression tree in the event a child is removed.
      Specified by:
      pruneNodeForPrunedChild in class Expression

    • expName

      public String expName()
      Implemented for backwards compatibility with exp package.
      Overrides:
      expName in class Expression

    • flattenTree

      protected void flattenTree()
      Flattens the tree under this node by eliminating any children that are of the same class as this node and copying their children to this node.
      Specified by:
      flattenTree in class Expression

    • appendAsString

      public void appendAsString(Appendable out) throws IOException
      Description copied from class: Expression
      Appends own content as a String to the provided Appendable.
      Specified by:
      appendAsString in class Expression
      Throws:
      IOException
      Since:
      4.0

    • getOperand

      public Object getOperand(int index)
      Description copied from class: Expression
      Returns a value of operand at index. Operand indexing starts at 0.
      Specified by:
      getOperand in class Expression

    • wrapChild

      protected Node wrapChild(Object child)

    • unwrapChild

      protected Object unwrapChild(Node child)

    • getOperandCount

      public int getOperandCount()
      Description copied from class: Expression
      Returns a count of operands of this expression. In real life there are unary (count == 1), binary (count == 2) and ternary (count == 3) expressions.
      Specified by:
      getOperandCount in class Expression

    • setOperand

      public void setOperand(int index, Object value)
      Description copied from class: Expression
      Sets a value of operand at index. Operand indexing starts at 0.
      Specified by:
      setOperand in class Expression

    • jjtOpen

      public void jjtOpen()
      Description copied from interface: Node
      Called after the node has been made the current node. It indicates that child nodes can now be added to it.
      Specified by:
      jjtOpen in interface Node

    • jjtClose

      public void jjtClose()
      Description copied from interface: Node
      Called after all the child nodes have been added.
      Specified by:
      jjtClose in interface Node

    • jjtSetParent

      public void jjtSetParent(Node n)
      Description copied from interface: Node
      This pair of methods are used to inform the node of its parent.
      Specified by:
      jjtSetParent in interface Node

    • jjtGetParent

      public Node jjtGetParent()
      Specified by:
      jjtGetParent in interface Node

    • jjtAddChild

      public void jjtAddChild(Node n, int i)
      Description copied from interface: Node
      This method tells the node to add its argument to the node's list of children.
      Specified by:
      jjtAddChild in interface Node

    • jjtGetChild

      public Node jjtGetChild(int i)
      Description copied from interface: Node
      This method returns a child node. The children are numbered from zero, left to right.
      Specified by:
      jjtGetChild in interface Node

    • jjtGetNumChildren

      public final int jjtGetNumChildren()
      Description copied from interface: Node
      Return the number of children the node has.
      Specified by:
      jjtGetNumChildren in interface Node

    • evaluateNode

      protected abstract Object evaluateNode(Object o) throws Exception
      Evaluates itself with object, pushing result on the stack.
      Throws:
      Exception

    • connectChildren

      protected void connectChildren()
      Sets the parent to this for all children.
      Since:
      3.0

    • evaluateChild

      protected Object evaluateChild(int index, Object o) throws Exception
      Throws:
      Exception

    • notExp

      public Expression notExp()
      Description copied from class: Expression
      Returns a logical NOT of current expression.
      Specified by:
      notExp in class Expression

    • evaluate

      public Object evaluate(Object o)
      Description copied from class: Expression
      Calculates expression value with object as a context for path expressions.
      Specified by:
      evaluate in class Expression

    • appendAsEJBQL

      public void appendAsEJBQL(Appendable out, String rootId) throws IOException
      Description copied from class: Expression
      Stores a String representation of Expression as EJBQL using a provided Appendable. DB path expressions produce non-standard EJBQL path expressions.
      Overrides:
      appendAsEJBQL in class Expression
      Throws:
      IOException
      Since:
      4.0

    • appendAsEJBQL

      public void appendAsEJBQL(List<Object> parameterAccumulator, Appendable out, String rootId) throws IOException
      Description copied from class: Expression
      Stores a String representation of Expression as EJBQL using a provided PrintWriter. DB path expressions produce non-standard EJBQL path expressions. If the parameterAccumulator is supplied then as the EJBQL is output, it may load parameters into this list. In this case, the EJBQL output will contain reference to positional parameters. If no parameterAccumulator is supplied and a scalar type is encountered for which there is no EJBQL literal representation (such as dates) then this method will throw a runtime exception to indicate that it was not possible to generate a string-only representation of the Expression in EJBQL.
      Specified by:
      appendAsEJBQL in class Expression
      Throws:
      IOException
      Since:
      4.0

    • appendChildrenAsEJBQL

      protected void appendChildrenAsEJBQL(List<Object> parameterAccumulator, Appendable out, String rootId) throws IOException
      Encodes child of this node with specified index to EJBQL
      Throws:
      IOException