Classes (The ZKoss Common Library 8.0.0 API)

java.lang.Object
- org.zkoss.lang.Classes

```
public class Classes
extends Object
```
Utilities to handle java.lang.Class

Author:

tomyeh

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Classes.MethodInfo
The method info class used for parseMethod(String signature).

Nested Classes
Modifier and Type	Class and Description
`static class`	`Classes.MethodInfo` The method info class used for `parseMethod(String signature)`.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`B_GET` Search the get method; not imply B_METHODONLY.
`static int`	`B_METHOD_ONLY` Only search for methods; excluding fields.
`static int`	`B_PUBLIC_ONLY` Only search for public methods or fields.
`static int`	`B_SET` Search the set method; not imply B_METHODONLY.

Constructor Summary

Constructors
Constructor and Description

Classes()

Constructors
Constructor and Description
`Classes()`

Method Summary

Methods
Modifier and Type	Method and Description
`static Object`	`coerce(Class<?> cls, Object val)` Converts an object to the specified class.
`static Object`	`coerce(Class<?> cls, Object val, boolean nullable)` Converts to the specified type.
`static boolean`	`containsMethod(Class<?> cls, String name, Class<?>[] paramTypes)` Tests whether a class contains the specified method.
`static String`	`correctFieldName(String name)` Corrects a string to a valid Java name.
`static boolean`	`existsByThread(String clsnm)` Returns whether the specified class exists for the current thread's context class loader.
`static Class<?>`	`forNameByThread(String clsName)` Returns the Class object of the specified class name, using the current thread's context class loader.
`static AccessibleObject`	`getAccessibleObject(Class<?> cls, String name, Class<?>[] argTypes, int flags)` Gets the specified accessible object, either a method or a field, by searching the specified name.
`static Class<?>[]`	`getAllInterfaces(Class<?> cls)` Returns all interfaces that are implemented by the specified class.
`static Field`	`getAnyField(Class<?> cls, String name)` Gets the specified field by searching all fields including any access control and any base class.
`static Method`	`getAnyMethod(Class<?> cls, String name, Class<?>[] argTypes)` Gets the specified method by searching all methods including any access control and any base class.
`static Method`	`getCloseMethod(Class<?> cls, String name, Class<?>[] argTypes)` Gets one of the close methods -- a close method is a method with the same name and the compatible argument type.
`static Method`	`getCloseMethodBySubclass(Class<?> cls, String name, Class<?>[] argTypes)` Like `getCloseMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[])` to get a 'close' method, but it look for subclass of the argument (instead of superclass).
`static Method[]`	`getCloseMethods(Class<?> cls, String name, Class<?>[] argTypes)` Returns all close methods that match the specified condition, or a zero-length array if none is found.
`static Method[]`	`getCloseMethodsBySubclass(Class<?> cls, String name, Class<?>[] argTypes)` Like `getCloseMethods(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[])` to get all 'close' methods, but it look for subclass of the argument (instead of superclass).
`static Method`	`getMethodByObject(Class<?> cls, String name, Object[] args)` Gets one of the close method by specifying the arguments, rather than the argument types.
`static Method`	`getMethodBySignature(Class<?> cls, String signature, Collection<String> params)` Gets the method based on the signature.
`static Method`	`getMethodBySignature(Class<?> cls, String signature, Collection<String> params, ClassResolver resolver)` Gets the method based on the signature with a class resolver.
`static Method`	`getMethodInPublic(Class<?> cls, String name, Class<?>[] argTypes)` Gets the method that is declared in a public class/interface.
`static Class<?>[]`	`getSuperClasses(Class<?> cls, Class<?>[] clsToCheck)` Searches thru each element of the specified array of classes, and returns classes that are super-classes (or equal) of the specified class.
`static Class<?>`	`getTopmostInterface(Class<?> cls, Class<?> subIF)` Gets the topmost interface of the specified class or interface that implements or extends the specified interface.
`static boolean`	`isAttribute(String methodName)` Tests if a method name is an attribute, i.e., prefixing with is, get or set.
`static boolean`	`isNumeric(Class<?> cls, boolean extend)` Checks whether the specified class is a numeric class.
`static boolean`	`isPrimitiveWrapper(Class<?> cls)` Check whether the specified class is a primitive or a primitive wrapper.
`static Object`	`newInstance(Class<?> cls, Class<?>[] argTypes, Object[] args)` Instantiates a new instance of the specified class with the specified arguments and argument types.
`static Object`	`newInstance(Class<?> cls, Object[] args)` Instantiates a new instance of the specified class with the specified argument.
`static Object`	`newInstance(String clsName, Class<?>[] argTypes, Object[] args)` Instantiates a new instance of the specified class name with the specified arguments.
`static Object`	`newInstanceByThread(String clsName)` Creates and initializes a new instance of the specified class name with default constructor, by use of `forNameByThread(java.lang.String)`.
`static Object`	`newInstanceByThread(String clsName, Class<?>[] argTypes, Object[] args)` Creates and initializes a new instance of the specified class name with the specified arguments, by use of `forNameByThread(java.lang.String)`.
`static Classes.MethodInfo`	`parseMethod(String signature)` Gets the method information from a signature.
`static String`	`toAttributeName(String methodName)` Converts a method name to an attribute name by removing the prefix is, get or set, or null if it doesn't start with is, get or set.
`static String`	`toInternalForm(String clsName)` Change class name to internal form (e.g. byte[] -> [B).
`static String`	`toMethodName(String attrName, String prefix)` Convert an attribute name, returned by toAttributeName, to a method name.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - B_GET
```
public static final int B_GET
```
    Search the get method; not imply B_METHODONLY.
    
    See Also:
    Constant Field Values
  - B_SET
```
public static final int B_SET
```
    Search the set method; not imply B_METHODONLY.
    
    See Also:
    Constant Field Values
  - B_PUBLIC_ONLY
```
public static final int B_PUBLIC_ONLY
```
    Only search for public methods or fields.
    
    See Also:
    Constant Field Values
  - B_METHOD_ONLY
```
public static final int B_METHOD_ONLY
```
    Only search for methods; excluding fields.
    
    See Also:
    Constant Field Values
- Constructor Detail
  - Classes
```
public Classes()
```
- Method Detail
  - newInstance
```
public static final Object newInstance(Class<?> cls,
                 Class<?>[] argTypes,
                 Object[] args)
                                throws NoSuchMethodException,
                                       InstantiationException,
                                       InvocationTargetException,
                                       IllegalAccessException
```
    Instantiates a new instance of the specified class with the specified arguments and argument types.
    Note only public constructors are searched.
    
    Parameters:
    cls - the class of the instance to create
    argTypes - the argument types of the constructor to invoke
    args - the arguments to initialize the instance
    
    Returns:
    the new instance
    
    Throws:
    
    NoSuchMethodException - if a matching method is not found
    
    InstantiationException - if the class that declares the underlying constructor represents an abstract class
    
    InvocationTargetException - if the underlying constructor throws an exception
    
    IllegalAccessException
    See Also:
    newInstance(String, Class[], Object[])
  - newInstance
```
public static final Object newInstance(Class<?> cls,
                 Object[] args)
                                throws NoSuchMethodException,
                                       InstantiationException,
                                       InvocationTargetException,
                                       IllegalAccessException
```
    Instantiates a new instance of the specified class with the specified argument.
    It searches all constructors for the first one that matches the specified arguments.
    
    Throws:
    
    NoSuchMethodException
    
    InstantiationException
    
    InvocationTargetException
    
    IllegalAccessException
    Since:
    
    3.0.1
  - newInstance
```
public static final Object newInstance(String clsName,
                 Class<?>[] argTypes,
                 Object[] args)
                                throws NoSuchMethodException,
                                       InstantiationException,
                                       InvocationTargetException,
                                       ClassNotFoundException,
                                       IllegalAccessException
```
    Instantiates a new instance of the specified class name with the specified arguments.
    It uses Class.forName to get the class.
    
    Parameters:
    clsName - the class name of the instance to create
    argTypes - the argument types of the constructor to invoke
    args - the arguments to initialize the instance
    
    Returns:
    the new instance
    
    Throws:
    
    NoSuchMethodException - if a matching method is not found
    
    InstantiationException - if the class that declares the underlying constructor represents an abstract class
    
    InvocationTargetException - if the underlying constructor throws an exception
    
    ClassNotFoundException - if the specified class name is not a class
    
    IllegalAccessException
    See Also:
    newInstance(Class, Class[], Object[])
  - newInstanceByThread
```
public static final Object newInstanceByThread(String clsName,
                         Class<?>[] argTypes,
                         Object[] args)
                                        throws NoSuchMethodException,
                                               InstantiationException,
                                               InvocationTargetException,
                                               ClassNotFoundException,
                                               IllegalAccessException
```
    Creates and initializes a new instance of the specified class name with the specified arguments, by use of forNameByThread(java.lang.String).
    It uses forNameByThread(java.lang.String) to get the class.
    
    Parameters:
    clsName - the class name of the instance to create
    argTypes - the argument types of the constructor to invoke
    args - the arguments to initialize the instance
    
    Returns:
    the new instance
    
    Throws:
    
    NoSuchMethodException - if a matching method is not found
    
    InstantiationException - if the class that declares the underlying constructor represents an abstract class
    
    InvocationTargetException - if the underlying constructor throws an exception
    
    ClassNotFoundException - if the specified class name is not a class
    
    IllegalAccessException
    See Also:
    newInstance(Class, Class[], Object[])
  - newInstanceByThread
```
public static final Object newInstanceByThread(String clsName)
                                        throws NoSuchMethodException,
                                               InstantiationException,
                                               InvocationTargetException,
                                               ClassNotFoundException,
                                               IllegalAccessException
```
    Creates and initializes a new instance of the specified class name with default constructor, by use of forNameByThread(java.lang.String).
    
    Throws:
    
    NoSuchMethodException
    
    InstantiationException
    
    InvocationTargetException
    
    ClassNotFoundException
    
    IllegalAccessException
  - forNameByThread
```
public static final Class<?> forNameByThread(String clsName)
                                      throws ClassNotFoundException
```
    Returns the Class object of the specified class name, using the current thread's context class loader.
    It first tries Thread.currentThread().getContextClassLoader(), and then Classes's class loader if not found.
    In additions, it handles the primitive types, such as int and double.
    
    Parameters:
    clsName - fully qualified name of the desired class
    
    Returns:
    the Class object representing the desired class
    
    Throws:
    
    ClassNotFoundException - if the class cannot be located by the specified class loader
  - existsByThread
```
public static final boolean existsByThread(String clsnm)
```
    Returns whether the specified class exists for the current thread's context class loader.
    
    Parameters:
    clsnm - the class name to test
    Since:
    
    3.0.7
  - toInternalForm
```
public static final String toInternalForm(String clsName)
```
    Change class name to internal form (e.g. byte[] -> [B). If already in internal form, then just return it.
  - getTopmostInterface
```
public static Class<?> getTopmostInterface(Class<?> cls,
                           Class<?> subIF)
```
    Gets the topmost interface of the specified class or interface that implements or extends the specified interface. For example, if A extends B, and C implements A, then getTopInterface(C, B) returns A.
    The interfaces implemented by the specified class is checked first, and then the subclass.
    
    Parameters:
    cls - the class or interface
    subIF - the sub-interface
    
    Returns:
    the topmost interface extending subIF, or null if subIF is not implemented by cls
  - getAllInterfaces
```
public static Class<?>[] getAllInterfaces(Class<?> cls)
```
    Returns all interfaces that are implemented by the specified class.
    Unlike Class.getInterfaces(), it recursively searches for all derived classes.
  - containsMethod
```
public static final boolean containsMethod(Class<?> cls,
                     String name,
                     Class<?>[] paramTypes)
```
    Tests whether a class contains the specified method. Only public methods are tested.
    
    Parameters:
    cls - the class to test
    name - the method name
    paramTypes - the list of parameter types
    
    Returns:
    true if it contains the method
  - correctFieldName
```
public static final String correctFieldName(String name)
```
    Corrects a string to a valid Java name. Currently, it only removes '-' and capitalizes the succeeding character. Example, 'field-name' becomes 'fieldName'.
  - toMethodName
```
public static final String toMethodName(String attrName,
                  String prefix)
```
    Convert an attribute name, returned by toAttributeName, to a method name.
    toMethodName("true", "is") => "isTrue"
    toMethodName("true", "") => "true"
    
    Parameters:
    attrName - the attribute name
    prefix - the prefix; one of is, get and set
    
    Returns:
    the method name
    See Also:
    toAttributeName(java.lang.String)
  - isAttribute
```
public static final boolean isAttribute(String methodName)
```
    Tests if a method name is an attribute, i.e., prefixing with is, get or set. Caller could then test if it is a setter or getter by charAt(0)=='s'.
    Note 'set' is considered as an attribute, whose name is an empty string.
    
    Parameters:
    methodName - the method name to test
    
    Returns:
    true if it is setter or getter
  - toAttributeName
```
public static final String toAttributeName(String methodName)
```
    Converts a method name to an attribute name by removing the prefix is, get or set, or null if it doesn't start with is, get or set.
    The code is optimized for better performance.
    
    Parameters:
    methodName - the method name
    
    Returns:
    the attribute name; null if it is not an attribute name
    See Also:
    toMethodName(java.lang.String, java.lang.String)
  - parseMethod
```
public static final Classes.MethodInfo parseMethod(String signature)
                                            throws IllegalSyntaxException
```
    Gets the method information from a signature. It returns a method info with the return type, method name and two collections of arguments type and arguments name.
    
    Parameters:
    signature - the method signature.
    
    Returns:
    MethodInfo The method information including return type, method name and two collections for argument type and arguments name.
    
    Throws:
    
    IllegalSyntaxException
  - getMethodBySignature
```
public static final Method getMethodBySignature(Class<?> cls,
                          String signature,
                          Collection<String> params,
                          ClassResolver resolver)
                                         throws NoSuchMethodException,
                                                ClassNotFoundException
```
    Gets the method based on the signature with a class resolver. It also returns the parameter names to the params list.
    Like getMethodInPublic(Class, String, Class[]), it returns only public method in a public class/interface.
    For example, "find(java.lang.String name)" will return the method with one String-typed argument and params will hold "name". The return type is optional (actually ignored).
    If params is null, the parameter names are not returned and the signature could be simplified as "find(java.lang.String)".
    A cache mechanism is implemented, so you don't need to cache it again in the caller.
    
    Parameters:
    cls - the class to look
    signature - the method signature; the return type is optional.
    Notice that the argument's type must be a full-qualified class name, unless its package is java.lang or it can be resolved by resolver.
    params - the collection to hold the parameter names returned; null means no parameter names to return
    resolver - the class resolver used to resolve the class specified in the signature. Ignored if null.
    
    Throws:
    
    NoSuchMethodException
    
    ClassNotFoundException
    Since:
    
    6.0.0
  - getMethodBySignature
```
public static final Method getMethodBySignature(Class<?> cls,
                          String signature,
                          Collection<String> params)
                                         throws NoSuchMethodException,
                                                ClassNotFoundException
```
    Gets the method based on the signature. It also returns the parameter names to the params list.
    Like getMethodInPublic(Class, String, Class[]), it returns only public method in a public class/interface.
    For example, "find(java.lang.String name)" will return the method with one String-typed argument and params will hold "name". The return type is optional (actually ignored).
    If params is null, the parameter names are not returned and the signature could be simplified as "find(java.lang.String)".
    A cache mechanism is implemented, so you don't need to cache it again in the caller.
    
    Parameters:
    cls - the class to look
    signature - the method signature; the return type is optional
    Notice that the argument's type must be a full-qualified class name, unless its package is java.lang.
    params - the collection to hold the parameter names returned; null means no parameter names to return
    
    Throws:
    
    NoSuchMethodException
    
    ClassNotFoundException
  - getMethodInPublic
```
public static final Method getMethodInPublic(Class<?> cls,
                       String name,
                       Class<?>[] argTypes)
                                      throws NoSuchMethodException
```
    Gets the method that is declared in a public class/interface.
    Class.getMethod returns a public method but the class itself might not be public. However, in many cases, that class also implements a public interface or class.
    This method will search all its public classes to look for the method that is 'real' public.
    NoSuchMethodException is thrown if no public class/interface is found to have the method.
    
    Throws:
    
    NoSuchMethodException
  - getMethodByObject
```
public static final Method getMethodByObject(Class<?> cls,
                       String name,
                       Object[] args)
                                      throws NoSuchMethodException
```
    Gets one of the close method by specifying the arguments, rather than the argument types. It actually calls getCloseMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[]).
    
    Throws:
    
    NoSuchMethodException
  - getCloseMethod
```
public static final Method getCloseMethod(Class<?> cls,
                    String name,
                    Class<?>[] argTypes)
                                   throws NoSuchMethodException
```
    Gets one of the close methods -- a close method is a method with the same name and the compatible argument type. By compatible we mean the real method's argument type is the same as or a superclass of the specified one.
    It might not be the best fit one, unless there is a method whose argument types are exactly argTypes.
    You might specify the exact number in argTypes. If any of them is unknown, use null. Example, in the following, the first argument could be anything and the second is anything deriving from MyClass:
    new Class[] {null, MyClass.class}
    Note: if an argument accepts int, then Integer is considered as compatible (unlike Class.getMethod). So are long, byte...
    A cache mechanism is implemented, so you don't need to cache it again in the caller.
    
    Parameters:
    cls - the class to locate the method
    name - the method name
    argTypes - an array of the argument classes; null to denote no argument at all (i.e., exact match). Any argTypes[i] could be null to denote any class.
    
    Returns:
    the method
    
    Throws:
    
    NoSuchMethodException - if the method is not found
  - getCloseMethodBySubclass
```
public static final Method getCloseMethodBySubclass(Class<?> cls,
                              String name,
                              Class<?>[] argTypes)
                                             throws NoSuchMethodException
```
    Like getCloseMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[]) to get a 'close' method, but it look for subclass of the argument (instead of superclass). In other words, it looks for the method whose argument type is the same as or a subclass of the specified one.
    
    Throws:
    
    NoSuchMethodException
  - getCloseMethods
```
public static final Method[] getCloseMethods(Class<?> cls,
                       String name,
                       Class<?>[] argTypes)
```
    Returns all close methods that match the specified condition, or a zero-length array if none is found.
    Unlike getCloseMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[]), we don't cache the searched result, and it won't throw any exception.
  - getCloseMethodsBySubclass
```
public static final Method[] getCloseMethodsBySubclass(Class<?> cls,
                                 String name,
                                 Class<?>[] argTypes)
```
    Like getCloseMethods(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[]) to get all 'close' methods, but it look for subclass of the argument (instead of superclass). In other words, it looks for the method whose argument type is the same as or a subclass of the specified one.
  - getAccessibleObject
```
public static final AccessibleObject getAccessibleObject(Class<?> cls,
                                   String name,
                                   Class<?>[] argTypes,
                                   int flags)
                                                  throws NoSuchMethodException
```
    Gets the specified accessible object, either a method or a field, by searching the specified name.
    The search sequence is: (assume field name is body)>
    getBody(...)
    isBody(...)
    body(...)
    body
    If B_SET is specified, setBody(...) is searched instead of getBody(...) and isBody(...). The field is searched only if argsType.length is 0 or 1.
    Note: it uses getCloseMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[]) to get the method.
    A cache mechanism is implemented, so you don't need to cache it again in the caller.
    
    Parameters:
    cls - the class to find
    name - the name of the accessible object
    argTypes - the parameter type of the method to find
    flags - a combination of B_xxx or zero
    
    Returns:
    the accessible object; either Field or Method
    
    Throws:
    
    NoSuchMethodException - if neither the set method of specified field nor the field itself not found
    
    SecurityException - if access to the information is denied
  - getAnyMethod
```
public static final Method getAnyMethod(Class<?> cls,
                  String name,
                  Class<?>[] argTypes)
                                 throws NoSuchMethodException
```
    Gets the specified method by searching all methods including any access control and any base class. Note: you rarely need to call this method. In most cases, Class.getMethod, getCloseMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[]), and getMethodInPublic(java.lang.Class<?>, java.lang.String, java.lang.Class<?>[]) are what you need.
    The search sequence is: this class's methods, and then the superclass's methods.
    Note: public methods don't be treated different. If the caller wants to search public methods first, it has to call Class.getMethod first.
    
    Parameters:
    cls - the class to search
    name - the method name
    argTypes - the parameter array of types
    
    Returns:
    the Method object
    
    Throws:
    
    NoSuchMethodException - if a matching method is not found.
    
    SecurityException - if access to the information is denied.
    See Also:
    getAccessibleObject(Class, String, Class[], int), getAnyField(Class, String)
  - getAnyField
```
public static final Field getAnyField(Class<?> cls,
                String name)
                               throws NoSuchFieldException
```
    Gets the specified field by searching all fields including any access control and any base class. The search sequence is: this class's fields, and then the superclass's fields.
    Note: public fields don't be treated different. If the caller wants to search public fields first, it has to call Class.getField first.
    
    Parameters:
    cls - the class to search
    name - the field name
    
    Returns:
    the Field object
    
    Throws:
    
    NoSuchFieldException - if a matching field is not found.
    
    SecurityException - if access to the information is denied.
    See Also:
    getAccessibleObject(Class, String, Class[], int), getAnyMethod(Class, String, Class[])
  - getSuperClasses
```
public static final Class<?>[] getSuperClasses(Class<?> cls,
                         Class<?>[] clsToCheck)
```
    Searches thru each element of the specified array of classes, and returns classes that are super-classes (or equal) of the specified class.
    
    Parameters:
    cls - the specified class; null is not allowed
    clsToCheck - the class array to check; null is acceptable
    
    Returns:
    a subset of clsToCheck that are super-class of cls; null if no one qualified
  - isPrimitiveWrapper
```
public static final boolean isPrimitiveWrapper(Class<?> cls)
```
    Check whether the specified class is a primitive or a primitive wrapper.
  - isNumeric
```
public static final boolean isNumeric(Class<?> cls,
                boolean extend)
```
    Checks whether the specified class is a numeric class.
    
    Parameters:
    extend - whether to consider Date, char, boolean, Character and Boolean as a numeric object.
  - coerce
```
public static Object coerce(Class<?> cls,
            Object val)
                     throws ClassCastException
```
    Converts an object to the specified class. It is the same as coerce(cls, val, true).
    
    Parameters:
    val - the value.
    
    Throws:
    
    ClassCastException - if failed to convert
    See Also:
    coerce(Class, Object, boolean)
  - coerce
```
public static Object coerce(Class<?> cls,
            Object val,
            boolean nullable)
                     throws ClassCastException
```
    Converts to the specified type.
    
    Parameters:
    nullable - whether the result could be null. If false, 0 is used for number, the default constructor is used for others. coerce(Class, Object) is a special case that is equivalent to nullable=true.
    
    Throws:
    
    ClassCastException - if failed to convert

Class Classes

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

B_GET

B_SET

B_PUBLIC_ONLY

B_METHOD_ONLY

Constructor Detail

Classes

Method Detail

newInstance

newInstance

newInstance

newInstanceByThread

newInstanceByThread

forNameByThread

existsByThread

toInternalForm

getTopmostInterface

getAllInterfaces

containsMethod

correctFieldName

toMethodName

isAttribute

toAttributeName

parseMethod

getMethodBySignature

getMethodBySignature

getMethodInPublic

getMethodByObject

getCloseMethod

getCloseMethodBySubclass

getCloseMethods

getCloseMethodsBySubclass

getAccessibleObject

getAnyMethod

getAnyField

getSuperClasses

isPrimitiveWrapper

isNumeric

coerce

coerce