org.apache.calcite.linq4j.tree

类 Types

java.lang.Object

org.apache.calcite.linq4j.tree.Types

public abstract class Types
extends Object

Utilities for converting between Expression, Type and Class.

另请参阅:

Primitive

嵌套类概要

嵌套类

限定符和类型	类和说明
static class	Types.ArrayType Array type.
static class	Types.MapType Map type.
static interface	Types.RecordField Field that belongs to a record.
static interface	Types.RecordType Base class for record-like types that do not mapped to (currently loaded) Java Class objects.

方法概要

限定符和类型	方法和说明
static boolean	allAssignable(boolean varArgs, Class[] parameterTypes, Class[] argumentTypes)
static Type	box(Type type)
static Expression	castIfNecessary(Type returnType, Expression expression) Wraps an expression in a cast if it is not already of the desired type, or cannot be implicitly converted to it.
static void	discard(Object o)
static PseudoField	field(Field field)
static @Nullable Type	getComponentType(Type type) Returns the component type of an array.
static @Nullable Type	getElementType(Type type) Returns the element type of a Collection, Iterable (including Queryable and Enumerable), Iterator, Enumerator, or an array.
static boolean	isArray(Type type)
static boolean	isAssignableFrom(Type type0, Type type)
static Constructor	lookupConstructor(Type type, Class... argumentTypes) Finds a constructor of a given class that accepts a given set of arguments.
static Field	lookupField(Type type, String name)
static Method	lookupMethod(Class clazz, String methodName, Class... argumentTypes) Finds a method of a given name that accepts a given set of arguments.
static boolean	needTypeCast(Type fromType, Type toType) When trying to cast/convert a Type to another Type, it is necessary to pre-check whether the cast operation is needed.
static Field	nthField(int ordinal, Class clazz)
static PseudoField	nthField(int ordinal, Type clazz)
static Type	of(Type type, Type... typeArguments) Creates a type with generic parameters.
static Type	stripGenerics(Type type)
static Class	toClass(Type type)
static Class[]	toClassArray(Iterable<? extends Expression> arguments)
static Type	unbox(Type type)

从类继承的方法 java.lang.Object

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

方法详细资料

of

public static Type of(Type type,
                      Type... typeArguments)

Creates a type with generic parameters.

getElementType

public static @Nullable Type getElementType(Type type)

Returns the element type of a Collection, Iterable (including Queryable and Enumerable), Iterator, Enumerator, or an array.

Returns null if the type is not one of these.

toClass

public static Class toClass(Type type)

toClassArray

public static Class[] toClassArray(Iterable<? extends Expression> arguments)

getComponentType

public static @Nullable Type getComponentType(Type type)

Returns the component type of an array.

box

public static Type box(Type type)

unbox

public static Type unbox(Type type)

isAssignableFrom

public static boolean isAssignableFrom(Type type0,
                                       Type type)

isArray

public static boolean isArray(Type type)

nthField

public static Field nthField(int ordinal,
                             Class clazz)

nthField

public static PseudoField nthField(int ordinal,
                                   Type clazz)

allAssignable

public static boolean allAssignable(boolean varArgs,
                                    Class[] parameterTypes,
                                    Class[] argumentTypes)

lookupMethod

public static Method lookupMethod(Class clazz,
                                  String methodName,
                                  Class... argumentTypes)

Finds a method of a given name that accepts a given set of arguments. Includes in its search inherited methods and methods with wider argument types.

参数:

clazz - Class against which method is invoked

methodName - Name of method

argumentTypes - Types of arguments

返回:

A method with the given name that matches the arguments given

抛出:

RuntimeException - if method not found

lookupConstructor

public static Constructor lookupConstructor(Type type,
                                            Class... argumentTypes)

Finds a constructor of a given class that accepts a given set of arguments. Includes in its search methods with wider argument types.

参数:

type - Class against which method is invoked

argumentTypes - Types of arguments

返回:

A method with the given name that matches the arguments given

抛出:

RuntimeException - if method not found

lookupField

public static Field lookupField(Type type,
                                String name)

discard

public static void discard(Object o)

castIfNecessary

public static Expression castIfNecessary(Type returnType,
                                         Expression expression)

Wraps an expression in a cast if it is not already of the desired type, or cannot be implicitly converted to it.

参数:

returnType - Desired type

expression - Expression

返回:

Expression of desired type

needTypeCast

public static boolean needTypeCast(Type fromType,
                                   Type toType)

When trying to cast/convert a Type to another Type, it is necessary to pre-check whether the cast operation is needed. We summarize general exceptions, including:

1. target Type toType equals with original Type fromType
2. target Type can be assignable from original Type
3. target Type is an instance of RecordType, since the mapping Java Class might not generated yet

参数:

fromType - original type

toType - target type

返回:

Whether a cast operation is needed

field

public static PseudoField field(Field field)

stripGenerics

public static Type stripGenerics(Type type)