io.burt.jmespath.function

Class ArgumentConstraints

java.lang.Object

io.burt.jmespath.function.ArgumentConstraints

public final class ArgumentConstraints
extends Object

A DSL for describing argument constraints of functions.

For example, this is how join describes its arguments:

 public JoinFunction() {
   super(
     ArgumentConstraints.typeOf(JmesPathType.STRING),
     ArgumentConstraints.arrayOf(ArgumentConstraints.typeOf(JmesPathType.STRING))
   );
 }
 

I.e. accept exactly two argument, where the first must be a string and the second must be an array of strings.

The static methods of this class can be used to compose constraints for most situations, but you can also create your own constraints (that can be combined with other constraints) by implementing the ArgumentConstraint interface.

Method Summary

Modifier and Type	Method and Description
static ArgumentConstraint	anyValue() Describes a single argument of any value.
static ArgumentConstraint	arrayOf(ArgumentConstraint constraint) Describes a single argument that is an array.
static ArgumentConstraint	expression() Describes a single expression argument.
static ArgumentConstraint	listOf(ArgumentConstraint... constraints) Describes a heterogeneous list of arguments.
static ArgumentConstraint	listOf(int min, ArgumentConstraint constraint) Describes a homogeneous list of arguments without upper limit.
static ArgumentConstraint	listOf(int min, int max, ArgumentConstraint constraint) Describes a homogeneous list of arguments, of fixed or variable length.
static ArgumentConstraint	typeOf(JmesPathType... types) Describes a single argument that is of one of the specified value types.
static ArgumentConstraint	typeOf(JmesPathType type) Describes a single argument of a specified value type.

Methods inherited from class java.lang.Object

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

Method Detail

listOf

public static ArgumentConstraint listOf(ArgumentConstraint... constraints)

Describes a heterogeneous list of arguments. Each argument is checked against the corresponding constraint. An ArityException will be thrown when the number of arguments does not exactly match the number of constraints.

May only be used as a top level constraint – and is already built in to Function, so direct usage of this method should not be needed.

listOf

public static ArgumentConstraint listOf(int min,
                                        int max,
                                        ArgumentConstraint constraint)

Describes a homogeneous list of arguments, of fixed or variable length. An ArityException will be thrown when there are fewer arguments than the specified minimum arity, or when there are more arguments than the specified maximum arity.

May only be used as a top level constraint.

listOf

public static ArgumentConstraint listOf(int min,
                                        ArgumentConstraint constraint)

Describes a homogeneous list of arguments without upper limit. An ArityException will be thrown when there are fewer arguments than the specified minimum arity.

May only be used as a top level constraint.

anyValue

public static ArgumentConstraint anyValue()

Describes a single argument of any value. An ArgumentTypeException will be thrown when the argument is an expression.

typeOf

public static ArgumentConstraint typeOf(JmesPathType type)

Describes a single argument of a specified value type. An ArgumentTypeException will be thrown when the argument is of the wrong type (as determined by Adapter.typeOf(T)) or is an expression.

typeOf

public static ArgumentConstraint typeOf(JmesPathType... types)

Describes a single argument that is of one of the specified value types. An ArgumentTypeException will be thrown when the argument is not of one of the specified types (as determined by Adapter.typeOf(T)) or is an expression.

arrayOf

public static ArgumentConstraint arrayOf(ArgumentConstraint constraint)

Describes a single argument that is an array. Each element in the array will be checked against the specified constraint. An ArgumentTypeException is thrown when the argument does not represent an array value.

expression

public static ArgumentConstraint expression()

Describes a single expression argument. An ArgumentTypeException will be thrown when the argument is not an expression.