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com.tangosol.util
Class ClassHelper

java.lang.Object
com.tangosol.util.ClassHelper

public abstract class ClassHelper

extends java.lang.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 Summary

static java.lang.Object[]	VOID Useful constant for methods with no arguments.
static java.lang.Class[]	VOID_PARAMS Useful constant for methods with no parameters.

Constructor Summary

ClassHelper()

Method Summary

static java.lang.reflect.Method	findMethod(java.lang.Class clz, java.lang.String sName, java.lang.Class[] aclzParam, boolean fStatic) Find a Method that matches the specified name and parameter types.
static java.lang.Class	getClass(java.lang.reflect.Type type) Obtains the most concrete runtime Class that may be used for the specified Type (taking generic declarations into account).
static java.lang.Class	getComponentType(java.lang.reflect.Type type) Obtains the component type of a collection or array (taking generic declarations into account).
static java.lang.String	getCompositeName(java.lang.Class clz, java.lang.String sName) Build the composite name of a class based on an existing class and a second class name.
static java.lang.String	getCompositeName(java.lang.String sName1, java.lang.String sName2) Build the composite name of a class based on an existing class name and a second class name.
static java.lang.String	getCompositePackage(java.lang.String pkg1, java.lang.String pkg2) Build the composite name of a package based on two package names.
static java.lang.String	getDerivedName(java.lang.Class clz, java.lang.String sPrefix) Build the name of a "derived" class based on an existing class and a "derived" class prefix.
static java.lang.String	getDerivedName(java.lang.String sName, java.lang.String sPrefix) Build the name of a "derived" class based on the name of an existing class and a "derived" class prefix.
static java.lang.String	getPackageName(java.lang.Class clz) Determine the package name of a class.
static java.lang.String	getPackageName(java.lang.String sName) Determine the package name from a class (or package) name.
static com.tangosol.util.Resources	getPackageResources(java.lang.Class clz) Load the default package resources for the specified class.
static com.tangosol.util.Resources	getPackageResources(java.lang.String sClass) Load the default package resources for the specified class name.
static java.lang.String	getQualifiedName(java.lang.String pkg, java.lang.String sName) Build the fully qualified name of a class based on a package name and a simple class name.
static java.util.Map	getReifiedTypes(java.lang.Class clz, java.lang.Class clzDefiningType) Returns a map of types by type name as defined in clzDefiningType.
static com.tangosol.util.Resources	getResources(java.lang.Class clz, java.lang.String sName) Load the named resources for the specified class.
static java.lang.String	getSimpleName(java.lang.Class clz) Determine the simple (unqualified) name of a class.
static java.lang.String	getSimpleName(java.lang.String sName) Determine the simple (unqualified) name of a class.
static java.lang.Object	invoke(java.lang.Class clz, java.lang.Object obj, java.lang.String sName, java.lang.Object[] aoParam) Invoke the specified method using the passed arguments.
static java.lang.Object	invoke(java.lang.Object obj, java.lang.String sName, java.lang.Object[] aoParam) Invoke the specified instance method using the passed arguments.
static java.lang.Object	invokeStatic(java.lang.Class clz, java.lang.String sName, java.lang.Object[] aoParam) Invoke the specified static method using the passed arguments.
static boolean	isInstanceOf(java.lang.Object obj, java.lang.Class clz) Determine if the passed object is an instance of the specified class.
static boolean	isInstanceOf(java.lang.Object obj, java.lang.String sClz) Determine if the passed object is an instance of the specified class.
static boolean	isPartialNameLegal(java.lang.String sName) Determine if a partial name (for example, a prefix, class name, package name, etc. as accepted by the above methods) is legal.
static boolean	isQualifiedNameLegal(java.lang.String sName) Determine if the passed string is a legal dot-delimited identifier.
static boolean	isSimpleNameLegal(java.lang.String sName) Determine if the passed string is a legal simple name.
static java.lang.Object	newInstance(java.lang.Class clz, java.lang.Object[] aoParam) Instantiate the specified class using the specified parameters.

Field Detail

VOID_PARAMS

public static final java.lang.Class[] VOID_PARAMS

Useful constant for methods with no parameters.

VOID

public static final java.lang.Object[] VOID

Useful constant for methods with no arguments.

Constructor Detail

ClassHelper

public ClassHelper()

Method Detail

isInstanceOf

public static boolean isInstanceOf(java.lang.Object obj,
                                   java.lang.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(java.lang.Object obj,
                                   java.lang.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 java.lang.String getPackageName(java.lang.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 java.lang.String getPackageName(java.lang.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 java.lang.String getSimpleName(java.lang.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 java.lang.String getSimpleName(java.lang.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 java.lang.String getQualifiedName(java.lang.String pkg,
                                                java.lang.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 java.lang.String getCompositePackage(java.lang.String pkg1,
                                                   java.lang.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 java.lang.String getCompositeName(java.lang.Class clz,
                                                java.lang.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 java.lang.String getCompositeName(java.lang.String sName1,
                                                java.lang.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 java.lang.String getDerivedName(java.lang.Class clz,
                                              java.lang.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 java.lang.String getDerivedName(java.lang.String sName,
                                              java.lang.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(java.lang.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(java.lang.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(java.lang.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

getPackageResources

public static com.tangosol.util.Resources getPackageResources(java.lang.String sClass)
                                                       throws java.util.MissingResourceException

Load the default package resources for the specified class name.

Parameters:

sClass - the class name (fully qualified) to get the resources for

Returns:

the resource bundle for the class's package

Throws:

java.util.MissingResourceException

See Also:

getResources(java.lang.Class, java.lang.String)

getPackageResources

public static com.tangosol.util.Resources getPackageResources(java.lang.Class clz)
                                                       throws java.util.MissingResourceException

Load the default package resources for the specified class.

Parameters:

clz - the class to get the resources for

Returns:

the resource bundle for the class's package

Throws:

java.util.MissingResourceException

See Also:

getResources(java.lang.Class, java.lang.String)

getResources

public static com.tangosol.util.Resources getResources(java.lang.Class clz,
                                                       java.lang.String sName)
                                                throws java.util.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:

java.util.MissingResourceException

newInstance

public static java.lang.Object newInstance(java.lang.Class clz,
                                           java.lang.Object[] aoParam)
                                    throws java.lang.InstantiationException,
                                           java.lang.reflect.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:

java.lang.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

java.lang.reflect.InvocationTargetException - if the constructor of the new object instance raises an exception

invokeStatic

public static java.lang.Object invokeStatic(java.lang.Class clz,
                                            java.lang.String sName,
                                            java.lang.Object[] aoParam)
                                     throws java.lang.NoSuchMethodException,
                                            java.lang.IllegalAccessException,
                                            java.lang.reflect.InvocationTargetException

Invoke the specified static method using the passed arguments.

Parameters:

clz - the class to invoke the static method of

sName - the method name

aoParam - the method arguments

Returns:

the return value (if any) from the method

Throws:

java.lang.NoSuchMethodException

java.lang.IllegalAccessException

java.lang.reflect.InvocationTargetException

invoke

public static java.lang.Object invoke(java.lang.Object obj,
                                      java.lang.String sName,
                                      java.lang.Object[] aoParam)
                               throws java.lang.NoSuchMethodException,
                                      java.lang.IllegalAccessException,
                                      java.lang.reflect.InvocationTargetException

Invoke the specified instance method using the passed arguments.

Parameters:

obj - the object to invoke the instance method of

sName - the method name

aoParam - the method arguments

Returns:

the return value (if any) from the method

Throws:

java.lang.NoSuchMethodException

java.lang.IllegalAccessException

java.lang.reflect.InvocationTargetException

invoke

public static java.lang.Object invoke(java.lang.Class clz,
                                      java.lang.Object obj,
                                      java.lang.String sName,
                                      java.lang.Object[] aoParam)
                               throws java.lang.NoSuchMethodException,
                                      java.lang.IllegalAccessException,
                                      java.lang.reflect.InvocationTargetException

Invoke the specified method using the passed arguments.

Parameters:

clz - the class to invoke the method on

obj - the object to invoke the method on

sName - the method name

aoParam - the method arguments

Returns:

the return value (if any) from the method invocation

Throws:

java.lang.NoSuchMethodException

java.lang.IllegalAccessException

java.lang.reflect.InvocationTargetException

findMethod

public static java.lang.reflect.Method findMethod(java.lang.Class clz,
                                                  java.lang.String sName,
                                                  java.lang.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 java.lang.Class getComponentType(java.lang.reflect.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 java.lang.Class getClass(java.lang.reflect.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 java.util.Map getReifiedTypes(java.lang.Class clz,
                                            java.lang.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

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