org.apache.hadoop.metrics2.util
Class Contracts

java.lang.Object
  org.apache.hadoop.metrics2.util.Contracts

public class Contracts
extends Object

Utilities for programming by contract (preconditions, postconditions etc.)

Method Summary

static double	checkArg(double arg, boolean expression, Object msg) Check an argument for false conditions
static float	checkArg(float arg, boolean expression, Object msg) Check an argument for false conditions
static int	checkArg(int arg, boolean expression, Object msg) Check an argument for false conditions
static long	checkArg(long arg, boolean expression, Object msg) Check an argument for false conditions
static <T> T	checkArg(T arg, boolean expression, Object msg) Check an argument for false conditions
static <T> T	checkNotNull(T ref, Object msg) Check that a reference is not null.
static void	checkState(boolean expression, Object msg) Check the state expression for false conditions

Methods inherited from class java.lang.Object

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

Method Detail

checkNotNull

public static <T> T checkNotNull(T ref,
                                 Object msg)

Check that a reference is not null.

Type Parameters:

T - type of the reference

Parameters:

ref - the reference to check

msg - the error message

Returns:

the checked reference for convenience

Throws:

NullPointerException - if ref is null

checkState

public static void checkState(boolean expression,
                              Object msg)

Check the state expression for false conditions

Parameters:

expression - the boolean expression to check

msg - the error message if expression is false

Throws:

IllegalStateException - if expression is false

checkArg

public static <T> T checkArg(T arg,
                             boolean expression,
                             Object msg)

Check an argument for false conditions

Type Parameters:

T - type of the argument

Parameters:

arg - the argument to check

expression - the boolean expression for the condition

msg - the error message if expression is false

Returns:

the argument for convenience

checkArg

public static int checkArg(int arg,
                           boolean expression,
                           Object msg)

Check an argument for false conditions

Parameters:

arg - the argument to check

expression - the boolean expression for the condition

msg - the error message if expression is false

Returns:

the argument for convenience

checkArg

public static long checkArg(long arg,
                            boolean expression,
                            Object msg)

Check an argument for false conditions

Parameters:

arg - the argument to check

expression - the boolean expression for the condition

msg - the error message if expression is false

Returns:

the argument for convenience

checkArg

public static float checkArg(float arg,
                             boolean expression,
                             Object msg)

Check an argument for false conditions

Parameters:

arg - the argument to check

expression - the boolean expression for the condition

msg - the error message if expression is false

Returns:

the argument for convenience

checkArg

public static double checkArg(double arg,
                              boolean expression,
                              Object msg)

Check an argument for false conditions

Parameters:

arg - the argument to check

expression - the boolean expression for the condition

msg - the error message if expression is false

Returns:

the argument for convenience