Package org.apache.calcite.util

Class ReflectUtil

  • public abstract class ReflectUtil
extends java.lang.Object
    Static utilities for Java reflection.

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static interface  ReflectUtil.MethodDispatcher<T>
      Can invoke a method on an object of type E with return type T.

    • Constructor Summary

      Constructors 
      Constructor Description
      ReflectUtil()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static <R extends ReflectiveVisitor,​E>
      ReflectiveVisitDispatcher<R,​E>      		 createDispatcher​(java.lang.Class<R> visitorBaseClazz, java.lang.Class<E> visiteeBaseClazz)
      Creates a dispatcher for calls to lookupVisitMethod(java.lang.Class<?>, java.lang.Class<?>, java.lang.String).
      static <E,​T>
      ReflectUtil.MethodDispatcher<T>      		 createMethodDispatcher​(java.lang.Class<T> returnClazz, ReflectiveVisitor visitor, java.lang.String methodName, java.lang.Class<E> arg0Clazz, java.lang.Class... otherArgClasses)
      Creates a dispatcher for calls to a single multi-method on a particular object.
      static java.lang.Class getBoxingClass​(java.lang.Class primitiveClass)
      Gets the Java boxing class for a primitive class.
      static java.lang.reflect.Method getByteBufferReadMethod​(java.lang.Class clazz)
      Uses reflection to find the correct java.nio.ByteBuffer "absolute get" method for a given primitive type.
      static java.lang.reflect.Method getByteBufferWriteMethod​(java.lang.Class clazz)
      Uses reflection to find the correct java.nio.ByteBuffer "absolute put" method for a given primitive type.
      static java.lang.String getParameterName​(java.lang.reflect.Method method, int i)
      Derives the name of the ith parameter of a method.
      static java.lang.String getUnmangledMethodName​(java.lang.Class declaringClass, java.lang.String methodName, java.lang.Class[] paramTypes)
      Composes a string representing a human-readable method name (with neither exception nor return type information).
      static java.lang.String getUnmangledMethodName​(java.lang.reflect.Method method)
      Composes a string representing a human-readable method name (with neither exception nor return type information).
      static java.lang.String getUnqualifiedClassName​(java.lang.Class c)
      Gets the name of a class with no package qualifiers; if it's an inner class, it will still be qualified by the containing class (X$Y).
      static boolean invokeVisitor​(ReflectiveVisitor visitor, java.lang.Object visitee, java.lang.Class hierarchyRoot, java.lang.String visitMethodName)
      Implements the Glossary.VISITOR_PATTERN via reflection.
      private static boolean invokeVisitorInternal​(java.lang.Object visitor, java.lang.Object visitee, java.lang.Class hierarchyRoot, java.lang.String visitMethodName)
      Shared implementation of the two forms of invokeVisitor.
      static boolean isParameterOptional​(java.lang.reflect.Method method, int i)
      Derives whether the ith parameter of a method is optional.
      static java.lang.reflect.Method lookupVisitMethod​(java.lang.Class<?> visitorClass, java.lang.Class<?> visiteeClass, java.lang.String visitMethodName)
      Looks up a visit method.
      private static java.lang.reflect.Method lookupVisitMethod​(java.lang.Class<?> visitorClass, java.lang.Class<?> visiteeClass, java.lang.String visitMethodName, java.lang.Class<?>[] paramTypes, java.util.Map<java.lang.Class<?>,​java.lang.reflect.Method> cache)  
      static java.lang.reflect.Method lookupVisitMethod​(java.lang.Class<?> visitorClass, java.lang.Class<?> visiteeClass, java.lang.String visitMethodName, java.util.List<java.lang.Class> additionalParameterTypes)
      Looks up a visit method taking additional parameters beyond the overloaded visitee type.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • primitiveToBoxingMap

        private static java.util.Map<java.lang.Class,​java.lang.Class> primitiveToBoxingMap

      • primitiveToByteBufferReadMethod

        private static java.util.Map<java.lang.Class,​java.lang.reflect.Method> primitiveToByteBufferReadMethod

      • primitiveToByteBufferWriteMethod

        private static java.util.Map<java.lang.Class,​java.lang.reflect.Method> primitiveToByteBufferWriteMethod

    • Constructor Detail

      • ReflectUtil

        public ReflectUtil()

    • Method Detail

      • getByteBufferReadMethod

        public static java.lang.reflect.Method getByteBufferReadMethod​(java.lang.Class clazz)
        Uses reflection to find the correct java.nio.ByteBuffer "absolute get" method for a given primitive type.
        Parameters:
        clazz - the Class object representing the primitive type
        Returns:
        corresponding method

      • getByteBufferWriteMethod

        public static java.lang.reflect.Method getByteBufferWriteMethod​(java.lang.Class clazz)
        Uses reflection to find the correct java.nio.ByteBuffer "absolute put" method for a given primitive type.
        Parameters:
        clazz - the Class object representing the primitive type
        Returns:
        corresponding method

      • getBoxingClass

        public static java.lang.Class getBoxingClass​(java.lang.Class primitiveClass)
        Gets the Java boxing class for a primitive class.
        Parameters:
        primitiveClass - representative class for primitive (e.g. java.lang.Integer.TYPE)
        Returns:
        corresponding boxing Class (e.g. java.lang.Integer)

      • getUnqualifiedClassName

        public static java.lang.String getUnqualifiedClassName​(java.lang.Class c)
        Gets the name of a class with no package qualifiers; if it's an inner class, it will still be qualified by the containing class (X$Y).
        Parameters:
        c - the class of interest
        Returns:
        the unqualified name

      • getUnmangledMethodName

        public static java.lang.String getUnmangledMethodName​(java.lang.Class declaringClass,
                                                      java.lang.String methodName,
                                                      java.lang.Class[] paramTypes)
        Composes a string representing a human-readable method name (with neither exception nor return type information).
        Parameters:
        declaringClass - class on which method is defined
        methodName - simple name of method without signature
        paramTypes - method parameter types
        Returns:
        unmangled method name

      • getUnmangledMethodName

        public static java.lang.String getUnmangledMethodName​(java.lang.reflect.Method method)
        Composes a string representing a human-readable method name (with neither exception nor return type information).
        Parameters:
        method - method whose name is to be generated
        Returns:
        unmangled method name

      • invokeVisitor

        public static boolean invokeVisitor​(ReflectiveVisitor visitor,
                                    java.lang.Object visitee,
                                    java.lang.Class hierarchyRoot,
                                    java.lang.String visitMethodName)
        Implements the Glossary.VISITOR_PATTERN via reflection. The basic technique is taken from a Javaworld article. For an example of how to use it, see ReflectVisitorTest.

        Visit method lookup follows the same rules as if compile-time resolution for VisitorClass.visit(VisiteeClass) were performed. An ambiguous match due to multiple interface inheritance results in an IllegalArgumentException. A non-match is indicated by returning false.

        Parameters:
        visitor - object whose visit method is to be invoked
        visitee - object to be passed as a parameter to the visit method
        hierarchyRoot - if non-null, visitor method will only be invoked if it takes a parameter whose type is a subtype of hierarchyRoot
        visitMethodName - name of visit method, e.g. "visit"
        Returns:
        true if a matching visit method was found and invoked

      • invokeVisitorInternal

        private static boolean invokeVisitorInternal​(java.lang.Object visitor,
                                             java.lang.Object visitee,
                                             java.lang.Class hierarchyRoot,
                                             java.lang.String visitMethodName)
        Shared implementation of the two forms of invokeVisitor.
        Parameters:
        visitor - object whose visit method is to be invoked
        visitee - object to be passed as a parameter to the visit method
        hierarchyRoot - if non-null, visitor method will only be invoked if it takes a parameter whose type is a subtype of hierarchyRoot
        visitMethodName - name of visit method, e.g. "visit"
        Returns:
        true if a matching visit method was found and invoked

      • lookupVisitMethod

        public static java.lang.reflect.Method lookupVisitMethod​(java.lang.Class<?> visitorClass,
                                                         java.lang.Class<?> visiteeClass,
                                                         java.lang.String visitMethodName)
        Looks up a visit method.
        Parameters:
        visitorClass - class of object whose visit method is to be invoked
        visiteeClass - class of object to be passed as a parameter to the visit method
        visitMethodName - name of visit method
        Returns:
        method found, or null if none found

      • lookupVisitMethod

        public static java.lang.reflect.Method lookupVisitMethod​(java.lang.Class<?> visitorClass,
                                                         java.lang.Class<?> visiteeClass,
                                                         java.lang.String visitMethodName,
                                                         java.util.List<java.lang.Class> additionalParameterTypes)
        Looks up a visit method taking additional parameters beyond the overloaded visitee type.
        Parameters:
        visitorClass - class of object whose visit method is to be invoked
        visiteeClass - class of object to be passed as a parameter to the visit method
        visitMethodName - name of visit method
        additionalParameterTypes - list of additional parameter types
        Returns:
        method found, or null if none found
        See Also:
        createDispatcher(Class, Class)

      • lookupVisitMethod

        private static java.lang.reflect.Method lookupVisitMethod​(java.lang.Class<?> visitorClass,
                                                          java.lang.Class<?> visiteeClass,
                                                          java.lang.String visitMethodName,
                                                          java.lang.Class<?>[] paramTypes,
                                                          java.util.Map<java.lang.Class<?>,​java.lang.reflect.Method> cache)

      • createMethodDispatcher

        public static <E,​T> ReflectUtil.MethodDispatcher<T> createMethodDispatcher​(java.lang.Class<T> returnClazz,
                                                                                 ReflectiveVisitor visitor,
                                                                                 java.lang.String methodName,
                                                                                 java.lang.Class<E> arg0Clazz,
                                                                                 java.lang.Class... otherArgClasses)
        Creates a dispatcher for calls to a single multi-method on a particular object.

        Calls to that multi-method are resolved by looking for a method on the runtime type of that object, with the required name, and with the correct type or a subclass for the first argument, and precisely the same types for other arguments.

        For instance, a dispatcher created for the method

        String foo(Vehicle, int, List)

        could be used to call the methods

        String foo(Car, int, List)
        String foo(Bus, int, List)

        (because Car and Bus are subclasses of Vehicle, and they occur in the polymorphic first argument) but not the method

        String foo(Car, int, ArrayList)

        (only the first argument is polymorphic).

        You must create an implementation of the method for the base class. Otherwise throws IllegalArgumentException.

        Parameters:
        returnClazz - Return type of method
        visitor - Object on which to invoke the method
        methodName - Name of method
        arg0Clazz - Base type of argument zero
        otherArgClasses - Types of remaining arguments

      • getParameterName

        public static java.lang.String getParameterName​(java.lang.reflect.Method method,
                                                int i)
        Derives the name of the ith parameter of a method.

      • isParameterOptional

        public static boolean isParameterOptional​(java.lang.reflect.Method method,
                                          int i)
        Derives whether the ith parameter of a method is optional.