Class UnifiedJEXL.Expression

java.lang.Object
org.apache.commons.jexl2.UnifiedJEXL.Expression
Enclosing class:
UnifiedJEXL
public abstract class UnifiedJEXL.Expression extends Object
The abstract base class for all expressions, immediate '${...}' and deferred '#{...}'.
Since:
2.0

  • Field Details

  • Method Details

    • isImmediate

      public boolean isImmediate()
      Checks whether this expression is immediate.
      Returns:
      true if immediate, false otherwise

    • isDeferred

      public final boolean isDeferred()
      Checks whether this expression is deferred.
      Returns:
      true if deferred, false otherwise

    • toString

      public String toString()
      Formats this expression, adding its source string representation in comments if available: 'expression /*= source *\/'' . Note: do not override; will be made final in a future release.
      Overrides:
      toString in class Object
      Returns:
      the formatted expression string

    • asString

      public String asString()
      Generates this expression's string representation.
      Returns:
      the string representation

    • asString

      public abstract StringBuilder asString(StringBuilder strb)
      Adds this expression's string representation to a StringBuilder.
      Parameters:
      strb - the builder to fill
      Returns:
      the builder argument

    • getVariables

      public Set<List<String>> getVariables()
      Gets the list of variables accessed by this expression.

      This method will visit all nodes of the sub-expressions and extract all variables whether they are written in 'dot' or 'bracketed' notation. (a.b is equivalent to a['b']).

      Returns:
      the set of variables, each as a list of strings (ant-ish variables use more than 1 string) or the empty set if no variables are used
      Since:
      2.1

    • getVariables

      protected void getVariables(Set<List<String>> refs)
      Fills up the list of variables accessed by this expression.
      Parameters:
      refs - the set of variable being filled
      Since:
      2.1

    • prepare

      public UnifiedJEXL.Expression prepare(JexlContext context)
      Evaluates the immediate sub-expressions.

      When the expression is dependant upon immediate and deferred sub-expressions, evaluates the immediate sub-expressions with the context passed as parameter and returns this expression deferred form.

      In effect, this binds the result of the immediate sub-expressions evaluation in the context, allowing to differ evaluation of the remaining (deferred) expression within another context. This only has an effect to nested & composite expressions that contain differed & immediate sub-expressions.

      If the underlying JEXL engine is silent, errors will be logged through its logger as warning.

      Note: do not override; will be made final in a future release.
      Parameters:
      context - the context to use for immediate expression evaluations
      Returns:
      an expression or null if an error occurs and the JexlEngine is running in silent mode
      Throws:
      UnifiedJEXL.Exception - if an error occurs and the JexlEngine is not in silent mode

    • evaluate

      public Object evaluate(JexlContext context)
      Evaluates this expression.

      If the underlying JEXL engine is silent, errors will be logged through its logger as warning.

      Note: do not override; will be made final in a future release.
      Parameters:
      context - the variable context
      Returns:
      the result of this expression evaluation or null if an error occurs and the JexlEngine is running in silent mode
      Throws:
      UnifiedJEXL.Exception - if an error occurs and the JexlEngine is not silent

    • getSource

      public final UnifiedJEXL.Expression getSource()
      Retrieves this expression's source expression. If this expression was prepared, this allows to retrieve the original expression that lead to it. Other expressions return themselves.
      Returns:
      the source expression

    • prepare

      protected UnifiedJEXL.Expression prepare(Interpreter interpreter)
      Prepares a sub-expression for interpretation.
      Parameters:
      interpreter - a JEXL interpreter
      Returns:
      a prepared expression
      Throws:
      JexlException - (only for nested & composite)

    • evaluate

      protected abstract Object evaluate(Interpreter interpreter)
      Intreprets a sub-expression.
      Parameters:
      interpreter - a JEXL interpreter
      Returns:
      the result of interpretation
      Throws:
      JexlException - (only for nested & composite)