de.unkrig.commons.lang

Class OptionalMethods

java.lang.Object

de.unkrig.commons.lang.OptionalMethods

public final class OptionalMethods
extends Object

Helpers for convenient handling of methods and classes that may or may be loadable at runtime, e.g. those which appeared in a later JRE version.

Example:

The JRE class "java.lang.Character" has a method "boolean isAlphabetic(int)", but only since Java 7, so you cannot invoke this method from your code if you compile it with JDK 6 (so that it is still runnable in a JRE 6). To make the method available for your code, proceed as follows:

 class MyClass {

     // ...

     private static final MethodWrapper1
     CHARACTER__IS_ALPHABETIC = OptionalMethods.get1(
         Character.class,       // declaringClass
         "isAlphabetic",        // methodName
         int.class,             // parameterType
         RuntimeException.class // checkedException
     );

     // ...

     public void m(int cp) {

         // Will throw an UnsupportedOperationException if this code runs in a JRE 6.
         if (CHARACTER__IS_ALPHABETIC.invoke(null, cp)) {
             // ...
         }

         // Alternatively, it is possible to check whether the wrapped method is available:
         if (CHARACTER__IS_ALPHABETIC.isAvailable() && CHARACTER__IS_ALPHABETIC.invoke(null, cp)) {
             // ...
         }
     }
 }
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	OptionalMethods.MethodWrapper0<DC,R,EX extends Throwable> Wrapper for a method with zero parameters.
static interface	OptionalMethods.MethodWrapper1<DC,R,P,EX extends Throwable> Wrapper for a method with one parameter.
static interface	OptionalMethods.MethodWrapper2<DC,R,P1,P2,EX extends Throwable> Wrapper for a method with two parameters.

Method Summary

Modifier and Type	Method and Description
static <DC,R> OptionalMethods.MethodWrapper0<DC,R,RuntimeException>	get0(Class<DC> declaringClass, String methodName) Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName.
static <DC,R,EX extends Throwable> OptionalMethods.MethodWrapper0<DC,R,EX>	get0(Class<DC> declaringClass, String methodName, Class<EX> checkedException) Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName.
static <R> OptionalMethods.MethodWrapper0<Object,R,RuntimeException>	get0(ClassLoader declaringClassLoader, String declaringClassName, String methodName) Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName.
static <R,EX extends Throwable> OptionalMethods.MethodWrapper0<Object,R,EX>	get0(ClassLoader declaringClassLoader, String declaringClassName, String methodName, Class<EX> checkedException) Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName.
static <DC,R,P> OptionalMethods.MethodWrapper1<DC,R,P,RuntimeException>	get1(Class<DC> declaringClass, String methodName, Class<P> parameterType) Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType.
static <DC,R,P,EX extends Throwable> OptionalMethods.MethodWrapper1<DC,R,P,EX>	get1(Class<DC> declaringClass, String methodName, Class<P> parameterType, Class<EX> checkedException) Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType.
static <R,P> OptionalMethods.MethodWrapper1<?,R,P,RuntimeException>	get1(ClassLoader declaringClassLoader, String declaringClassName, String methodName, Class<P> parameterType) Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType.
static <R,P,EX extends Throwable> OptionalMethods.MethodWrapper1<?,R,P,EX>	get1(ClassLoader declaringClassLoader, String declaringClassName, String methodName, Class<P> parameterType, Class<EX> checkedException) Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType.
static <DC,R,P1,P2> OptionalMethods.MethodWrapper2<DC,R,P1,P2,RuntimeException>	get2(Class<DC> declaringClass, String methodName, Class<P1> parameterType1, Class<P2> parameterType2) Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2.
static <DC,R,P1,P2,EX extends Throwable> OptionalMethods.MethodWrapper2<DC,R,P1,P2,EX>	get2(Class<DC> declaringClass, String methodName, Class<P1> parameterType1, Class<P2> parameterType2, Class<EX> checkedException) Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2.
static <R,P1,P2> OptionalMethods.MethodWrapper2<?,R,P1,P2,RuntimeException>	get2(ClassLoader declaringClassLoader, String declaringClassName, String methodName, Class<P1> parameterType1, Class<P2> parameterType2) Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2.
static <R,P1,P2,EX extends Throwable> OptionalMethods.MethodWrapper2<?,R,P1,P2,EX>	get2(ClassLoader declaringClassLoader, String declaringClassName, String methodName, Class<P1> parameterType1, Class<P2> parameterType2, Class<EX> checkedException) Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2.

Methods inherited from class java.lang.Object

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

Method Detail

get0

public static <R> OptionalMethods.MethodWrapper0<Object,R,RuntimeException> get0(@Nullable
                                                                                 ClassLoader declaringClassLoader,
                                                                                 String declaringClassName,
                                                                                 String methodName)

Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

R - The return type of the method

get0

public static <R,EX extends Throwable> OptionalMethods.MethodWrapper0<Object,R,EX> get0(@Nullable
                                                                                        ClassLoader declaringClassLoader,
                                                                                        String declaringClassName,
                                                                                        String methodName,
                                                                                        @Nullable
                                                                                        Class<EX> checkedException)

Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

R - The return type of the method

EX - The (single) checked exception declared for the method

get0

public static <DC,R> OptionalMethods.MethodWrapper0<DC,R,RuntimeException> get0(Class<DC> declaringClass,
                                                                                String methodName)

Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

DC - The class that declares the method

R - The return type of the method

get0

public static <DC,R,EX extends Throwable> OptionalMethods.MethodWrapper0<DC,R,EX> get0(Class<DC> declaringClass,
                                                                                       String methodName,
                                                                                       @Nullable
                                                                                       Class<EX> checkedException)

Returns a wrapper for a zero-parameter method of the declaringClass, based on the methodName. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

DC - The class that declares the method

R - The return type of the method

EX - The (single) checked exception declared for the method

get1

public static <R,P> OptionalMethods.MethodWrapper1<?,R,P,RuntimeException> get1(@Nullable
                                                                                ClassLoader declaringClassLoader,
                                                                                String declaringClassName,
                                                                                String methodName,
                                                                                Class<P> parameterType)

Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

R - The return type of the wrapped method

P - The type of the single parameter of the wrapped method

get1

public static <R,P,EX extends Throwable> OptionalMethods.MethodWrapper1<?,R,P,EX> get1(@Nullable
                                                                                       ClassLoader declaringClassLoader,
                                                                                       String declaringClassName,
                                                                                       String methodName,
                                                                                       Class<P> parameterType,
                                                                                       @Nullable
                                                                                       Class<EX> checkedException)

Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

R - The return type of the wrapped method

P - The type of the single parameter of the wrapped method

EX - The (single) checked exception declared for the method

get1

public static <DC,R,P> OptionalMethods.MethodWrapper1<DC,R,P,RuntimeException> get1(Class<DC> declaringClass,
                                                                                    String methodName,
                                                                                    Class<P> parameterType)

Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

DC - The class that declares the wrapped method

R - The return type of the wrapped method

P - The type of the single parameter of the wrapped method

get1

public static <DC,R,P,EX extends Throwable> OptionalMethods.MethodWrapper1<DC,R,P,EX> get1(Class<DC> declaringClass,
                                                                                           String methodName,
                                                                                           Class<P> parameterType,
                                                                                           @Nullable
                                                                                           Class<EX> checkedException)

Returns a wrapper for a single-parameter method of the declaringClass, based on methodName and parameterType. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

DC - The class that declares the wrapped method

R - The return type of the wrapped method

P - The type of the single parameter of the wrapped method

EX - The (single) checked exception declared for the method

get2

public static <R,P1,P2> OptionalMethods.MethodWrapper2<?,R,P1,P2,RuntimeException> get2(@Nullable
                                                                                        ClassLoader declaringClassLoader,
                                                                                        String declaringClassName,
                                                                                        String methodName,
                                                                                        Class<P1> parameterType1,
                                                                                        Class<P2> parameterType2)

Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

R - The return type of the wrapped method

P1 - The type of the first parameter of the wrapped method

P2 - The type of the second parameter of the wrapped method

get2

public static <R,P1,P2,EX extends Throwable> OptionalMethods.MethodWrapper2<?,R,P1,P2,EX> get2(@Nullable
                                                                                               ClassLoader declaringClassLoader,
                                                                                               String declaringClassName,
                                                                                               String methodName,
                                                                                               Class<P1> parameterType1,
                                                                                               Class<P2> parameterType2,
                                                                                               @Nullable
                                                                                               Class<EX> checkedException)

Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

R - The return type of the wrapped method

P1 - The type of the first parameter of the wrapped method

P2 - The type of the second parameter of the wrapped method

EX - The (single) checked exception declared for the method

get2

public static <DC,R,P1,P2> OptionalMethods.MethodWrapper2<DC,R,P1,P2,RuntimeException> get2(Class<DC> declaringClass,
                                                                                            String methodName,
                                                                                            Class<P1> parameterType1,
                                                                                            Class<P2> parameterType2)

Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

DC - The class that declares the wrapped method

R - The return type of the wrapped method

P1 - The type of the first parameter of the wrapped method

P2 - The type of the second parameter of the wrapped method

get2

public static <DC,R,P1,P2,EX extends Throwable> OptionalMethods.MethodWrapper2<DC,R,P1,P2,EX> get2(Class<DC> declaringClass,
                                                                                                   String methodName,
                                                                                                   Class<P1> parameterType1,
                                                                                                   Class<P2> parameterType2,
                                                                                                   @Nullable
                                                                                                   Class<EX> checkedException)

Returns a wrapper for a two-parameter method of the declaringClass, based on methodName, parameterType1 and parameterType2. If that method does not exist, a wrapper is returned that will throw an UnsupportedOperationException when invoked.

Type Parameters:

DC - The class that declares the wrapped method

R - The return type of the wrapped method

P1 - The type of the first parameter of the wrapped method

P2 - The type of the second parameter of the wrapped method

EX - The (single) checked exception declared for the method