Package com.tangosol.util

Class ClassHelper

  • public abstract class ClassHelper
extends Object
    This abstract class contains dynamic (reflect-based) class, method, and field manipulation methods.

    Note: This class is primarily for supporting generated code.

    Version:
    1.00, 11/22/96
    Author:
    Cameron Purdy

    • Field Detail

      • VOID_PARAMS

        public static final Class[] VOID_PARAMS
        Useful constant for methods with no parameters.

      • VOID

        public static final Object[] VOID
        Useful constant for methods with no arguments.

      • REFLECT_FILTER_SEPARATOR

        public static final String REFLECT_FILTER_SEPARATOR
        Separator for filter patterns.
        See Also:
        Constant Field Values

      • REFLECT_FILTER_PROPERTY

        public static final String REFLECT_FILTER_PROPERTY
        Configure reflection allowed class white list and/or black list by setting the value of this system property to a set of patterns.

        Patterns are separated by ";" (semicolon). Whitespace is significant and is considered part of the pattern.

        • If the pattern starts with "!", the class is rejected if the remaining pattern is matched; otherwise the class is allowed if the pattern matches.
        • If the pattern ends with ".**" it matches any class in the package and all subpackages.
        • If the pattern ends with ".*" it matches any class in the package.
        • If the pattern ends with "*", it matches any class with the pattern as a prefix.
        • If the pattern is equal to the class name, it matches.
        • Otherwise, the pattern is not matched.

        The resulting filter tries to match the class, if any. The first pattern that matches, working from left to right, determines if a reflection is allowed on a class by the filter or rejected. If none of the patterns match the class, reflection will be allowed.

        See Also:
        Constant Field Values

      • DEFAULT_REFLECT_ALLOWED_BLACKLIST

        public static final String DEFAULT_REFLECT_ALLOWED_BLACKLIST
        Default reflection filter list which disables reflection against the following types:
        • java.lang.Class
        • java.lang.System
        • java.lang.Runtime
        See Also:
        Constant Field Values

    • Constructor Detail

      • ClassHelper

        public ClassHelper()

    • Method Detail

      • isInstanceOf

        public static boolean isInstanceOf​(Object obj,
                                   String sClz)
        Determine if the passed object is an instance of the specified class.
        Parameters:
        obj - the object
        sClz - the class name
        Returns:
        true iff the passed object is an instance of the specified class

      • isInstanceOf

        public static boolean isInstanceOf​(Object obj,
                                   Class clz)
        Determine if the passed object is an instance of the specified class.
        Parameters:
        obj - the object
        clz - the class
        Returns:
        true iff the passed object is an instance of the specified class

      • getPackageName

        public static String getPackageName​(Class clz)
        Determine the package name of a class.
        Parameters:
        clz - the class to determine the package of
        Returns:
        the name of the package, including a trailing dot (which signifies that the string is a package name)

      • getPackageName

        public static String getPackageName​(String sName)
        Determine the package name from a class (or package) name. 
           in      out
   ------- -------
   [blank] [blank]
   a       [blank]
   .a      .a.
   a.      a.
   .a.     .a.
   a.b     a.
   .a.b    .a.
   a.b.    a.b.
   .a.b.   .a.b.
        Parameters:
        sName - the class name to determine the package of
        Returns:
        the name of the package, including a trailing dot (which signifies that the string is a package name)

      • getSimpleName

        public static String getSimpleName​(Class clz)
        Determine the simple (unqualified) name of a class.
        Parameters:
        clz - the class to determine the simple name of
        Returns:
        the simple name of the class

      • getSimpleName

        public static String getSimpleName​(String sName)
        Determine the simple (unqualified) name of a class. 
           in      out
   ------- -------
   [blank] [blank]
   a       a
   .a      [blank]
   a.      [blank]
   .a.     [blank]
   a.b     b
   .a.b    b
   a.b.    [blank]
   .a.b.   [blank]
        Parameters:
        sName - the simple or qualified name of the class (or package)
        Returns:
        the simple name of the class

      • getQualifiedName

        public static String getQualifiedName​(String pkg,
                                      String sName)
        Build the fully qualified name of a class based on a package name and a simple class name.
        Parameters:
        pkg - package name
        sName - simple class name
        Returns:
        fully qualified class name

      • getCompositePackage

        public static String getCompositePackage​(String pkg1,
                                         String pkg2)
        Build the composite name of a package based on two package names. If there is a conflict, the second package name over-rides the first. 
           pkg1        pkg2            composite
   ----------- --------------  ----------------------
   [blank]     [blank]         [blank]
   [blank]     yourpkg.        yourpkg.
   [blank]     .yourpkg.       .yourpkg.
   mypkg.      [blank]         mypkg.
   .mypkg.     [blank]         .mypkg.
   mypkg.      yourpkg.        yourpkg.
   mypkg.      .yourpkg.       mypkg.yourpkg.
   .mypkg.     .yourpkg.       .mypkg.yourpkg.
        Parameters:
        pkg1 - the first (base) package
        pkg2 - the second (extending/overriding) package
        Returns:
        the composite package name, including a trailing dot

      • getCompositeName

        public static String getCompositeName​(Class clz,
                                      String sName)
        Build the composite name of a class based on an existing class and a second class name.
        Parameters:
        clz - the existing class
        sName - the name to use to build the composite class name
        Returns:
        the composite name of the class

      • getCompositeName

        public static String getCompositeName​(String sName1,
                                      String sName2)
        Build the composite name of a class based on an existing class name and a second class name. For example: 
           Class       Name           Derived
   ----------- -------------- ----------------------
   Test        Net            Net
   mypkg.Test  Net            mypkg.Net
   mypkg.Test  yourpkg.       yourpkg.Test
   mypkg.Test  .yourpkg       mypkg.yourpkg.Test
   mypkg.Test  .yourpkg.      mypkg.yourpkg.Test
   mypkg.Test  yourpkg.Net    yourpkg.Net
   mypkg.Test  .yourpkg.Net   mypkg.yourpkg.Net
   mypkg.Test  .yourpkg.Net.  mypkg.yourpkg.Net.Test
        Parameters:
        sName1 - the existing class name
        sName2 - the name to use to build the composite class name
        Returns:
        the composite name of the class

      • getDerivedName

        public static String getDerivedName​(Class clz,
                                    String sPrefix)
        Build the name of a "derived" class based on an existing class and a "derived" class prefix.
        Parameters:
        clz - the existing class
        sPrefix - the prefix to apply to the existing class to determine the name of the "derived" class
        Returns:
        the expected name of the "derived" class

      • getDerivedName

        public static String getDerivedName​(String sName,
                                    String sPrefix)
        Build the name of a "derived" class based on the name of an existing class and a "derived" class prefix. For example: 
           Class       Prefix        Derived
   ----------- ------------- ----------------------
   Test        Net           NetTest
   mypkg.Test  Net           mypkg.NetTest
   mypkg.Test  yourpkg.      yourpkg.Test
   mypkg.Test  .yourpkg      mypkg.yourpkg.Test
   mypkg.Test  .yourpkg.     mypkg.yourpkg.Test
   mypkg.Test  yourpkg.Net   yourpkg.NetTest
   mypkg.Test  .yourpkg.Net  mypkg.yourpkg.NetTest
   mypkg.Test  .yourpkg.Net. mypkg.yourpkg.Net.Test
        Parameters:
        sName - the existing class name
        sPrefix - the prefix to apply to the existing class to determine the name of the "derived" class
        Returns:
        the expected name of the "derived" class

      • isPartialNameLegal

        public static boolean isPartialNameLegal​(String sName)
        Determine if a partial name (for example, a prefix, class name, package name, etc. as accepted by the above methods) is legal.
        Parameters:
        sName - the partial name
        Returns:
        true if the name is a legal partial name

      • isSimpleNameLegal

        public static boolean isSimpleNameLegal​(String sName)
        Determine if the passed string is a legal simple name. This does not check if the name is reserved by the Java language.
        Parameters:
        sName - the string containing the name
        Returns:
        true if a legal name, false otherwise

      • isQualifiedNameLegal

        public static boolean isQualifiedNameLegal​(String sName)
        Determine if the passed string is a legal dot-delimited identifier.
        Parameters:
        sName - the string containing the dot-delimited identifier
        Returns:
        true if a legal identifier, false otherwise

      • getClassArray

        public static Class[] getClassArray​(Object[] aoParam)
        Calculate the class array based on the parameter array.
        Parameters:
        aoParam - the parameter array
        Returns:
        the class array based on the parameter array

      • unwrap

        public static Class[] unwrap​(Class[] aClasses)
        Replace wrapper types with appropriate primitive types.
        Parameters:
        aClasses - an array of classes
        Returns:
        the class array with primitive instead of wrapper types

      • getResources

        public static com.tangosol.util.Resources getResources​(Class clz,
                                                       String sName)
                                                throws MissingResourceException
        Load the named resources for the specified class.
        Parameters:
        clz - the class to get the resources for
        sName - the name of the resource class
        Returns:
        the resource bundle for the class's package
        Throws:
        MissingResourceException

      • newInstance

        public static Object newInstance​(Class clz,
                                 Object[] aoParam)
                          throws InstantiationException,
                                 InvocationTargetException
        Instantiate the specified class using the specified parameters.
        Parameters:
        clz - the class to instantiate
        aoParam - the constructor parameters
        Returns:
        a new instance of the specified class
        Throws:
        InstantiationException - if an exception is raised trying to instantiate the object, whether the exception is a security, method access, no such method, or instantiation exception
        InvocationTargetException - if the constructor of the new object instance raises an exception

      • findMethod

        public static Method findMethod​(Class clz,
                                String sName,
                                Class[] aclzParam,
                                boolean fStatic)
        Find a Method that matches the specified name and parameter types. If there are more than one matching methods, the first one will be returned.
        Parameters:
        clz - the class reference
        sName - the method name
        aclzParam - the parameter types (some array elements could be null)
        fStatic - the method scope flag
        Returns:
        the matching Method object or null if no match could be found

      • getComponentType

        public static Class<?> getComponentType​(Type type)
        Obtains the component type of a collection or array (taking generic declarations into account).
        Parameters:
        type - the collection or array Type
        Returns:
        the component type of the collection or null if the specified class is not a collection

      • getClass

        public static Class<?> getClass​(Type type)
        Obtains the most concrete runtime Class that may be used for the specified Type (taking generic declarations into account).
        Parameters:
        type - the Type
        Returns:
        the runtime Class for the Type.

      • getReifiedTypes

        public static Map<String,​Type[]> getReifiedTypes​(Class<?> clz,
                                                       Class<?> clzDefiningType)
        Returns a map of types by type name as defined in clzDefiningType. Each type is reified by traversing the class hierarchy commencing from the first found reference of clzDefiningType in clz. The traversing completes when either a concrete substitution is found or the hierarchy can no longer be traversed, in which case the bounds will be returned. 
        
     public class MyCallable
             implements Callable<Boolean>
         {
         ...
         }

     Map<String, Type[]> mapTypes = ClassHelper.getReifiedTypes(MyCallable.class, Callable.class);
     assert mapTypes.get("V")[0] == Boolean.class;
        The returned map is ordered thus can be traversed assuming each entry being returned is in the same order as the definition of the generic types in clzDefiningType.
        Parameters:
        clz - the concrete class that can be assigned to clzDefiningType
        clzDefiningType - the class (interface or abstract class) that holds the types to be reified
        Returns:
        a map of types by type name

      • getFullyQualifiedClassNameOf

        public static String getFullyQualifiedClassNameOf​(String sAbbreviatedClassName)
        Determines the fully qualified class name of the Coherence-style abbreviated class name.
        Parameters:
        sAbbreviatedClassName - the abbreviated class name (or a regular class name)
        Returns:
        the fully qualified class name

      • isReflectionAllowed

        public static boolean isReflectionAllowed​(Object oTarget)
        Returns true if oTarget is a valid type for reflection operations.
        Parameters:
        oTarget - the reflection target
        Returns:
        true if oTarget is a valid type for reflection operations