org.apache.cayenne.exp.parser

## Class ASTScalar

- java.lang.Object
- - org.apache.cayenne.exp.Expression
  - - org.apache.cayenne.exp.parser.SimpleNode
    - - org.apache.cayenne.exp.parser.ASTScalar

- All Implemented Interfaces:
    Serializable, Node, XMLSerializable
  Direct Known Subclasses:
    ASTEnum, ASTNamedParameter

      public class ASTScalar
      extends SimpleNode

  A scalar value wrapper expression.
  Since:
    1.1
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected Object` | `value`

    - ### Fields inherited from class org.apache.cayenne.exp.parser.SimpleNode

      `children, id, parent`

    - ### Fields inherited from class org.apache.cayenne.exp.Expression

      `ADD, AND, ASTERISK, BETWEEN, BITWISE_AND, BITWISE_LEFT_SHIFT, BITWISE_NOT, BITWISE_OR, BITWISE_RIGHT_SHIFT, BITWISE_XOR, CUSTOM_OP, DB_PATH, DBID_PATH, DIVIDE, ENCLOSING_OBJECT, EQUAL_TO, EXISTS, FALSE, FULL_OBJECT, FUNCTION_CALL, GREATER_THAN, GREATER_THAN_EQUAL_TO, IN, LESS_THAN, LESS_THAN_EQUAL_TO, LIKE, LIKE_IGNORE_CASE, LIST, MULTIPLY, NEGATIVE, NOT, NOT_BETWEEN, NOT_EQUAL_TO, NOT_EXISTS, NOT_IN, NOT_LIKE, NOT_LIKE_IGNORE_CASE, OBJ_PATH, OR, PRUNED_NODE, SUBQUERY, SUBTRACT, TRUE, type`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ASTScalar()`
    `ASTScalar(Object value)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `appendAsEJBQL(List<Object> parameterAccumulator, Appendable out, String rootId)` Stores a String representation of Expression as EJBQL using a provided PrintWriter.
    `void` | `appendAsString(Appendable out)` Appends own content as a String to the provided Appendable.
    `boolean` | `equals(Object o)`
    `protected Object` | `evaluateNode(Object o)` Evaluates itself with object, pushing result on the stack.
    `protected String` | `getExpressionOperator(int index)`
    `Object` | `getValue()`
    `int` | `hashCode()`
    `void` | `setValue(Object value)`
    `Expression` | `shallowCopy()` Creates a copy of this expression node, without copying children.

    - ### Methods inherited from class org.apache.cayenne.exp.parser.SimpleNode

      `appendAsEJBQL, appendAsEscapedString, appendChildrenAsEJBQL, appendScalarAsString, connectChildren, encodeScalarAsEJBQL, evaluate, evaluateChild, expName, flattenTree, getEJBQLExpressionOperator, getOperand, getOperandCount, getPathAliases, jjtAddChild, jjtClose, jjtGetChild, jjtGetNumChildren, jjtGetParent, jjtOpen, jjtSetParent, notExp, pruneNodeForPrunedChild, setOperand, unwrapChild, wrapChild`

    - ### Methods inherited from class org.apache.cayenne.exp.Expression

      `andExp, andExp, deepCopy, encodeAsXML, filter, filterObjects, first, getType, joinExp, joinExp, match, orExp, orExp, params, params, paramsArray, setType, toEJBQL, toEJBQL, toString, transform, transformExpression, traverse, traverse`

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### value

          protected Object value

  - ### Constructor Detail

    - #### ASTScalar

          public ASTScalar()

    - #### ASTScalar

          public ASTScalar(Object value)

  - ### Method Detail

    - #### evaluateNode

          protected Object evaluateNode(Object o)
                                 throws Exception

      Description copied from class: `SimpleNode`
      Evaluates itself with object, pushing result on the stack.
      Specified by:
        `evaluateNode` in class `SimpleNode`
      Throws:
        `Exception`

    - #### shallowCopy

          public Expression shallowCopy()

      Creates a copy of this expression node, without copying children.
      Specified by:
        `shallowCopy` 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.
      Overrides:
        `appendAsString` in class `SimpleNode`
      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.
      Overrides:
        `appendAsEJBQL` in class `SimpleNode`
      Throws:
        `IOException`
      Since:
        4.0

    - #### setValue

          public void setValue(Object value)

    - #### getValue

          public Object getValue()

    - #### getExpressionOperator

          protected String getExpressionOperator(int index)

      Specified by:
        `getExpressionOperator` in class `SimpleNode`

    - #### equals

          public boolean equals(Object o)

      Overrides:
        `equals` in class `Expression`

    - #### hashCode

          public int hashCode()

      Overrides:
        `hashCode` in class `Expression`

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