Package org.apache.hadoop.util.dynamic

Class BindingUtils

java.lang.Object

org.apache.hadoop.util.dynamic.BindingUtils

@LimitedPrivate("testing")
@Unstable
public final class BindingUtils
extends java.lang.Object

Utility methods to assist binding to Hadoop APIs through reflection. Source: org.apache.parquet.hadoop.util.wrapped.io.BindingUtils.

Method Summary

Modifier and Type	Method	Description
static boolean	available(DynMethods.UnboundMethod method)	Is a method available?
static void	checkAvailable(DynMethods.UnboundMethod method)	Require a method to be available.
static <T> T	extractIOEs(java.util.function.Supplier<T> call)	Invoke the supplier, catching any UncheckedIOException raised, extracting the inner IOException and rethrowing it.
static boolean	implemented(DynMethods.UnboundMethod... methods)	Given a sequence of methods, verify that they are all available.
static java.lang.Class<?>	loadClass(java.lang.ClassLoader cl, java.lang.String className)	Load a class by name.
static java.lang.Class<?>	loadClass(java.lang.String className)	Load a class by name.
static java.lang.Class<?>	loadClassSafely(java.lang.String className)	Load a class by name.
static <T> DynMethods.UnboundMethod	loadInvocation(java.lang.Class<?> source, java.lang.Class<? extends T> returnType, java.lang.String name, java.lang.Class<?>... parameterTypes)	Get an invocation from the source class, which will be unavailable() if the class is null or the method isn't found.
static <T> DynMethods.UnboundMethod	loadStaticMethod(java.lang.Class<?> source, java.lang.Class<? extends T> returnType, java.lang.String name, java.lang.Class<?>... parameterTypes)	Load a static method from the source class, which will be a noop() if the class is null or the method isn't found.
static DynMethods.UnboundMethod	noop(java.lang.String name)	Create a no-op method.

Methods inherited from class java.lang.Object

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

Method Detail

loadClass

public static java.lang.Class<?> loadClass(java.lang.String className)

Load a class by name.

Parameters:

className - classname

Returns:

the class or null if it could not be loaded.

loadClassSafely

public static java.lang.Class<?> loadClassSafely(java.lang.String className)

Load a class by name.

Parameters:

className - classname

Returns:

the class.

Throws:

java.lang.RuntimeException - if the class was not found.

loadClass

public static java.lang.Class<?> loadClass(java.lang.ClassLoader cl,
                                           java.lang.String className)

Load a class by name.

Parameters:

cl - classloader to use.

className - classname

Returns:

the class or null if it could not be loaded.

loadInvocation

public static <T> DynMethods.UnboundMethod loadInvocation(java.lang.Class<?> source,
                                                          java.lang.Class<? extends T> returnType,
                                                          java.lang.String name,
                                                          java.lang.Class<?>... parameterTypes)

Get an invocation from the source class, which will be unavailable() if the class is null or the method isn't found.

Type Parameters:

T - return type

Parameters:

source - source. If null, the method is a no-op.

returnType - return type class (unused)

name - method name

parameterTypes - parameters

Returns:

the method or "unavailable"

loadStaticMethod

public static <T> DynMethods.UnboundMethod loadStaticMethod(java.lang.Class<?> source,
                                                            java.lang.Class<? extends T> returnType,
                                                            java.lang.String name,
                                                            java.lang.Class<?>... parameterTypes)

Load a static method from the source class, which will be a noop() if the class is null or the method isn't found. If the class and method are not found, then an IllegalStateException is raised on the basis that this means that the binding class is broken, rather than missing/out of date.

Type Parameters:

T - return type

Parameters:

source - source. If null, the method is a no-op.

returnType - return type class (unused)

name - method name

parameterTypes - parameters

Returns:

the method or a no-op.

Throws:

java.lang.IllegalStateException - if the method is not static.

noop

public static DynMethods.UnboundMethod noop(java.lang.String name)

Create a no-op method.

Parameters:

name - method name

Returns:

a no-op method.

implemented

public static boolean implemented(DynMethods.UnboundMethod... methods)

Given a sequence of methods, verify that they are all available.

Parameters:

methods - methods

Returns:

true if they are all implemented

checkAvailable

public static void checkAvailable(DynMethods.UnboundMethod method)
                           throws java.lang.UnsupportedOperationException

Require a method to be available.

Parameters:

method - method to probe

Throws:

java.lang.UnsupportedOperationException - if the method was not found.

available

public static boolean available(DynMethods.UnboundMethod method)

Is a method available?

Parameters:

method - method to probe

Returns:

true iff the method is found and loaded.

extractIOEs

public static <T> T extractIOEs(java.util.function.Supplier<T> call)
                         throws java.io.IOException

Invoke the supplier, catching any UncheckedIOException raised, extracting the inner IOException and rethrowing it.

Type Parameters:

T - type of result

Parameters:

call - call to invoke

Returns:

result

Throws:

java.io.IOException - if the call raised an IOException wrapped by an UncheckedIOException.