org.apache.hadoop.metrics2.util
Class Contracts

java.lang.Object
  extended by 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


Copyright © 2009 The Apache Software Foundation