Package org.apache.commons.discovery.tools

Class ClassUtils

  • public class ClassUtils
extends java.lang.Object
    Various utilities to interact with Class types.

    • Constructor Summary

      Constructors 
      Constructor Description
      ClassUtils()  

    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method Description
      static java.lang.reflect.Method findPublicStaticMethod​(java.lang.Class<?> clazz, java.lang.Class<?> returnType, java.lang.String methodName, java.lang.Class<?>[] paramTypes)
      Looks for public static returnType methodName(paramTypes).
      static java.lang.String getPackageName​(java.lang.Class<?> clazz)
      Get package name.
      static <T> T newInstance​(java.lang.Class<T> impl, java.lang.Class<?>[] paramClasses, java.lang.Object[] params)
      Creates a new instance of the input class using the following policy: if paramClasses or params is null, the default constructor will be used; the public constructor with paramClasses arguments type, with params as arguments value, will be used.
      static void setLog​(org.apache.commons.logging.Log _log)
      Deprecated.
      This method is not thread-safe
      static void verifyAncestory​(java.lang.Class<?> spi, java.lang.Class<?> impl)
      Throws exception if impl does not implement or extend the SPI.

      • Methods inherited from class java.lang.Object

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

    • Method Detail

      • setLog

        @Deprecated
public static void setLog​(org.apache.commons.logging.Log _log)
        Deprecated.
        This method is not thread-safe
        Sets the Log for this class.
        Parameters:
        _log - This class Log

      • getPackageName

        public static java.lang.String getPackageName​(java.lang.Class<?> clazz)
        Get package name. Not all class loaders 'keep' package information, in which case Class.getPackage() returns null. This means that calling Class.getPackage().getName() is unreliable at best.
        Parameters:
        clazz - The class from which the package has to be extracted
        Returns:
        The string representation of the input class package

      • findPublicStaticMethod

        public static java.lang.reflect.Method findPublicStaticMethod​(java.lang.Class<?> clazz,
                                                              java.lang.Class<?> returnType,
                                                              java.lang.String methodName,
                                                              java.lang.Class<?>[] paramTypes)
        Looks for public static returnType methodName(paramTypes).
        Parameters:
        clazz - The class where looking for the method
        returnType - The method return type
        methodName - The method name
        paramTypes - The method arguments types
        Returns:
        Method public static returnType methodName(paramTypes), if found to be directly implemented by clazz.

      • newInstance

        public static <T> T newInstance​(java.lang.Class<T> impl,
                                java.lang.Class<?>[] paramClasses,
                                java.lang.Object[] params)
                         throws DiscoveryException,
                                java.lang.InstantiationException,
                                java.lang.IllegalAccessException,
                                java.lang.NoSuchMethodException,
                                java.lang.reflect.InvocationTargetException
        Creates a new instance of the input class using the following policy:
        • if paramClasses or params is null, the default constructor will be used;
        • the public constructor with paramClasses arguments type, with params as arguments value, will be used.
        Type Parameters:
        T - The class type has to be instantiated
        Parameters:
        impl - The class has to be instantiated
        paramClasses - The constructor arguments types (can be null)
        params - The constructor arguments values (can be null)
        Returns:
        A new class instance
        Throws:
        DiscoveryException - if the class implementing the SPI cannot be found, cannot be loaded and instantiated, or if the resulting class does not implement (or extend) the SPI
        java.lang.InstantiationException - see Class.newInstance()
        java.lang.IllegalAccessException - see Class.newInstance()
        java.lang.NoSuchMethodException - see Class.newInstance()
        java.lang.reflect.InvocationTargetException - see Class.newInstance()

      • verifyAncestory

        public static void verifyAncestory​(java.lang.Class<?> spi,
                                   java.lang.Class<?> impl)
                            throws DiscoveryException
        Throws exception if impl does not implement or extend the SPI.
        Parameters:
        spi - The SPI type
        impl - The class has to be verified is a SPI implementation/extension
        Throws:
        DiscoveryException - if the input implementation class is not an SPI implementation