Apache Commons Lang 3.20.0 · org.apache.commons.lang3.function.MethodInvokers

Converts Method objects to lambdas.

More specifically, produces instances of single-method interfaces which redirect calls to methods; see asInterfaceInstance(Class, Method).

Calling supplier methods with no arguments

If the interface's single-method defines no arguments, use asFunction(Method) and then apply the function passing in the object to receive the method call.

For example to invoke String#length():

final Method method = String.class.getMethod("length");
final Function<String, Integer> function = MethodInvokers.asFunction(method);
assertEquals(3, function.apply("ABC"));

Calling function methods with one argument

If the interface's single-method defines one argument, use asBiFunction(Method) and then apply the function passing in the object to receive the method call. The second argument to the function is the only argument to the method.

For example to invoke String#charAt(int):

final Method method = String.class.getMethod("charAt", int.class);
final BiFunction<String, Integer, Character> function = MethodInvokers.asBiFunction(method);
assertEquals('C', function.apply("ABC", 2));

Constructor Summary

Access	Constructor and Description
private	MethodInvokers() No need to create instances.

Method Summary

Modifier and Type	Method and Description
public static < the type of the first argument to the operation: The type containing the Method. T, the type of the second argument to the operation: The type of the method argument. U> BiConsumer<T, U>	Returns: a correctly-typed wrapper for the given target. asBiConsumer(final Method the method to invoke. method) Produces a `BiConsumer` for a given consumer Method.
public static < the type of the first argument to the function: The type containing the method. T, the type of the second argument to the function: the method argument type. U, the type of the result of the function: The method return type. R> BiFunction<T, U, R>	Returns: a correctly-typed wrapper for the given target. asBiFunction(final Method the method to invoke. method) Produces a `BiFunction` for a given a function Method.
public static < the type of the first argument to the operation: The type containing the Method. T, the type of the second argument to the operation: The type of the method argument. U> FailableBiConsumer<T, U, Throwable>	Returns: a correctly-typed wrapper for the given target. asFailableBiConsumer(final Method the method to invoke. method) Produces a `FailableBiConsumer` for a given consumer Method.
public static < the type of the first argument to the function: The type containing the method. T, the type of the second argument to the function: the method argument type. U, the type of the result of the function: The method return type. R> FailableBiFunction<T, U, R, Throwable>	Returns: a correctly-typed wrapper for the given target. asFailableBiFunction(final Method the method to invoke. method) Produces a `FailableBiFunction` for a given a function Method.
public static < the type of the first argument to the function: The type containing the method. T, the type of the result of the function: The method return type. R> FailableFunction<T, R, Throwable>	Returns: a correctly-typed wrapper for the given target. asFailableFunction(final Method the method to invoke. method) Produces a `FailableFunction` for a given a supplier Method.
public static < The Method return type. R> FailableSupplier<R, Throwable>	Returns: a correctly-typed wrapper for the given target. asFailableSupplier(final Method the method to invoke. method) Produces a `FailableSupplier` for a given a supplier Method.
public static < the type of the first argument to the function: The type containing the method. T, the type of the result of the function: The method return type. R> Function<T, R>	Returns: a correctly-typed wrapper for the given target. asFunction(final Method the method to invoke. method) Produces a `Function` for a given a supplier Method.
public static < The interface type. T> T	Returns: a correctly-typed wrapper for the given target. asInterfaceInstance(final Class<T> a class object representing `T`. interfaceClass, final Method the method to invoke. method) Produces an instance of the given single-method interface which redirects its calls to the given method.
public static < The Method return type. R> Supplier<R>	Returns: a correctly-typed wrapper for the given target. asSupplier(final Method the method to invoke. method) Produces a `Supplier` for a given a supplier Method.
private static Method	Returns: The given method. requireMethod(final Method The method to test. method) Throws NullPointerException if `method` is `null`.
private static MethodHandle	unreflect(final Method method)
private static MethodHandle	unreflectUnchecked(final Method method)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

MethodInvokers	back to summary
private MethodInvokers() No need to create instances.

Method Detail

asBiConsumer back to summary

asBiConsumer	back to summary
public static <T, U> BiConsumer<T, U> asBiConsumer(final Method method) Produces a `BiConsumer` for a given consumer Method. For example, a classic setter method (as opposed to a fluent setter). You call the BiConsumer with two arguments: (1) the object receiving the method call, and (2) the method argument. Parameters <T> the type of the first argument to the operation: The type containing the Method. <U> the type of the second argument to the operation: The type of the method argument. method:Method the method to invoke. Returns:BiConsumer<T, U> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <T, U> BiConsumer<T, U> asBiConsumer(final Method method)

Produces a BiConsumer for a given consumer Method. For example, a classic setter method (as opposed to a fluent setter). You call the BiConsumer with two arguments: (1) the object receiving the method call, and (2) the method argument.

Parameters

<T>: the type of the first argument to the operation: The type containing the Method.
<U>: the type of the second argument to the operation: The type of the method argument.
method:Method: the method to invoke.

Returns:BiConsumer<T, U>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

asBiFunction back to summary

asBiFunction	back to summary
public static <T, U, R> BiFunction<T, U, R> asBiFunction(final Method method) Produces a `BiFunction` for a given a function Method. You call the BiFunction with two arguments: (1) the object receiving the method call, and (2) the method argument. The BiFunction return type must match the method's return type. For example to invoke `String#charAt(int)`: `final Method method = String.class.getMethod("charAt", int.class); final BiFunction<String, Integer, Character> function = MethodInvokers.asBiFunction(method); assertEquals('C', function.apply("ABC", 2));` Parameters <T> the type of the first argument to the function: The type containing the method. <U> the type of the second argument to the function: the method argument type. <R> the type of the result of the function: The method return type. method:Method the method to invoke. Returns:BiFunction<T, U, R> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <T, U, R> BiFunction<T, U, R> asBiFunction(final Method method)

Produces a BiFunction for a given a function Method. You call the BiFunction with two arguments: (1) the object receiving the method call, and (2) the method argument. The BiFunction return type must match the method's return type.

For example to invoke String#charAt(int):

final Method method = String.class.getMethod("charAt", int.class);
final BiFunction<String, Integer, Character> function = MethodInvokers.asBiFunction(method);
assertEquals('C', function.apply("ABC", 2));

Parameters

<T>: the type of the first argument to the function: The type containing the method.
<U>: the type of the second argument to the function: the method argument type.
<R>: the type of the result of the function: The method return type.
method:Method: the method to invoke.

Returns:BiFunction<T, U, R>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

asFailableBiConsumer back to summary

asFailableBiConsumer	back to summary
public static <T, U> FailableBiConsumer<T, U, Throwable> asFailableBiConsumer(final Method method) Produces a `FailableBiConsumer` for a given consumer Method. For example, a classic setter method (as opposed to a fluent setter). You call the FailableBiConsumer with two arguments: (1) the object receiving the method call, and (2) the method argument. Parameters <T> the type of the first argument to the operation: The type containing the Method. <U> the type of the second argument to the operation: The type of the method argument. method:Method the method to invoke. Returns:FailableBiConsumer<T, U, Throwable> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <T, U> FailableBiConsumer<T, U, Throwable> asFailableBiConsumer(final Method method)

Produces a FailableBiConsumer for a given consumer Method. For example, a classic setter method (as opposed to a fluent setter). You call the FailableBiConsumer with two arguments: (1) the object receiving the method call, and (2) the method argument.

Parameters

<T>: the type of the first argument to the operation: The type containing the Method.
<U>: the type of the second argument to the operation: The type of the method argument.
method:Method: the method to invoke.

Returns:FailableBiConsumer<T, U, Throwable>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

asFailableBiFunction back to summary

asFailableBiFunction	back to summary
public static <T, U, R> FailableBiFunction<T, U, R, Throwable> asFailableBiFunction(final Method method) Produces a `FailableBiFunction` for a given a function Method. You call the FailableBiFunction with two arguments: (1) the object receiving the method call, and (2) the method argument. The BiFunction return type must match the method's return type. Parameters <T> the type of the first argument to the function: The type containing the method. <U> the type of the second argument to the function: the method argument type. <R> the type of the result of the function: The method return type. method:Method the method to invoke. Returns:FailableBiFunction<T, U, R, Throwable> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <T, U, R> FailableBiFunction<T, U, R, Throwable> asFailableBiFunction(final Method method)

Produces a FailableBiFunction for a given a function Method. You call the FailableBiFunction with two arguments: (1) the object receiving the method call, and (2) the method argument. The BiFunction return type must match the method's return type.

Parameters

<T>: the type of the first argument to the function: The type containing the method.
<U>: the type of the second argument to the function: the method argument type.
<R>: the type of the result of the function: The method return type.
method:Method: the method to invoke.

Returns:FailableBiFunction<T, U, R, Throwable>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

asFailableFunction back to summary

asFailableFunction	back to summary
public static <T, R> FailableFunction<T, R, Throwable> asFailableFunction(final Method method) Produces a `FailableFunction` for a given a supplier Method. You call the Function with one argument: the object receiving the method call. The FailableFunction return type must match the method's return type. Parameters <T> the type of the first argument to the function: The type containing the method. <R> the type of the result of the function: The method return type. method:Method the method to invoke. Returns:FailableFunction<T, R, Throwable> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <T, R> FailableFunction<T, R, Throwable> asFailableFunction(final Method method)

Produces a FailableFunction for a given a supplier Method. You call the Function with one argument: the object receiving the method call. The FailableFunction return type must match the method's return type.

Parameters

<T>: the type of the first argument to the function: The type containing the method.
<R>: the type of the result of the function: The method return type.
method:Method: the method to invoke.

Returns:FailableFunction<T, R, Throwable>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

asFailableSupplier back to summary

asFailableSupplier	back to summary
public static <R> FailableSupplier<R, Throwable> asFailableSupplier(final Method method) Produces a `FailableSupplier` for a given a supplier Method. The FailableSupplier return type must match the method's return type. Only works with static methods. Parameters <R> The Method return type. method:Method the method to invoke. Returns:FailableSupplier<R, Throwable> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <R> FailableSupplier<R, Throwable> asFailableSupplier(final Method method)

Produces a FailableSupplier for a given a supplier Method. The FailableSupplier return type must match the method's return type.

Only works with static methods.

Parameters

<R>: The Method return type.
method:Method: the method to invoke.

Returns:FailableSupplier<R, Throwable>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

asFunction back to summary

asFunction	back to summary
public static <T, R> Function<T, R> asFunction(final Method method) Produces a `Function` for a given a supplier Method. You call the Function with one argument: the object receiving the method call. The Function return type must match the method's return type. For example to invoke `String#length()`: `final Method method = String.class.getMethod("length"); final Function<String, Integer> function = MethodInvokers.asFunction(method); assertEquals(3, function.apply("ABC"));` Parameters <T> the type of the first argument to the function: The type containing the method. <R> the type of the result of the function: The method return type. method:Method the method to invoke. Returns:Function<T, R> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <T, R> Function<T, R> asFunction(final Method method)

Produces a Function for a given a supplier Method. You call the Function with one argument: the object receiving the method call. The Function return type must match the method's return type.

For example to invoke String#length():

final Method method = String.class.getMethod("length");
final Function<String, Integer> function = MethodInvokers.asFunction(method);
assertEquals(3, function.apply("ABC"));

Parameters

<T>: the type of the first argument to the function: The type containing the method.
<R>: the type of the result of the function: The method return type.
method:Method: the method to invoke.

Returns:Function<T, R>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

asInterfaceInstance back to summary

asInterfaceInstance	back to summary
public static <T> T asInterfaceInstance(final Class<T> interfaceClass, final Method method) Produces an instance of the given single-method interface which redirects its calls to the given method. For the definition of "single-method", see `MethodHandleProxies#asInterfaceInstance(Class, MethodHandle)`. Parameters <T> The interface type. interfaceClass:Class<T> a class object representing `T`. method:Method the method to invoke. Returns:T a correctly-typed wrapper for the given target. See Also `MethodHandleProxies#asInterfaceInstance(Class, MethodHandle)`

public static <T> T asInterfaceInstance(final Class<T> interfaceClass, final Method method)

Produces an instance of the given single-method interface which redirects its calls to the given method.

For the definition of "single-method", see MethodHandleProxies#asInterfaceInstance(Class, MethodHandle).

Parameters

<T>: The interface type.
interfaceClass:Class<T>: a class object representing T.
method:Method: the method to invoke.

Returns:T

a correctly-typed wrapper for the given target.

asSupplier back to summary

asSupplier	back to summary
public static <R> Supplier<R> asSupplier(final Method method) Produces a `Supplier` for a given a supplier Method. The Supplier return type must match the method's return type. Only works with static methods. Parameters <R> The Method return type. method:Method the method to invoke. Returns:Supplier<R> a correctly-typed wrapper for the given target. Annotations @SuppressWarnings:unchecked

public static <R> Supplier<R> asSupplier(final Method method)

Produces a Supplier for a given a supplier Method. The Supplier return type must match the method's return type.

Only works with static methods.

Parameters

<R>: The Method return type.
method:Method: the method to invoke.

Returns:Supplier<R>

a correctly-typed wrapper for the given target.

Annotations

@SuppressWarnings:unchecked

requireMethod back to summary

requireMethod	back to summary
private static Method requireMethod(final Method method) Throws NullPointerException if `method` is `null`. Parameters method:Method The method to test. Returns:Method The given method. Exceptions NullPointerException: if `method` is `null`.

private static Method requireMethod(final Method method)

Throws NullPointerException if method is null.

Parameters

method:Method: The method to test.

Returns:Method

The given method.

Exceptions

NullPointerException:: if method is null.

unreflect	back to summary
private static MethodHandle unreflect(final Method method) throws IllegalAccessException

unreflectUnchecked	back to summary
private static MethodHandle unreflectUnchecked(final Method method)

public final Class MethodInvokers

Calling supplier methods with no arguments

Calling function methods with one argument

Constructor Summary

Method Summary

Constructor Detail

Method Detail