com.jgoodies.common.base
Class Preconditions

java.lang.Object
  com.jgoodies.common.base.Preconditions

public final class Preconditions
extends Object

Reduces the code necessary to check preconditions on method state an parameters.

Version:

$Revision: 1.3 $

Author:

Karsten Lentzsch

Method Summary

static void	checkArgument(boolean expression, String message) Checks the truth of the given expression and throws a customize IllegalArgumentException if it is false.
static void	checkArgument(boolean expression, String messageFormat, Object... messageArgs) Checks the truth of the given expression and throws a customize IllegalArgumentException if it is false.
static String	checkNotBlank(String str, String message) Checks that the given string is not blank and throws a customize NullPointerException if it is null, and a customize IllegalArgumentException if it is empty or whitespace.
static String	checkNotBlank(String str, String messageFormat, Object... messageArgs) Checks that the given string is not blank and throws a customize NullPointerException if it is null, and a customize IllegalArgumentException if it is empty or whitespace.
static <T> T	checkNotNull(T reference, String message) Checks that the given object reference is not nullNullPointerException if it is.
static <T> T	checkNotNull(T reference, String messageFormat, Object... messageArgs) Checks that the given object reference is not nullNullPointerException if it is.
static void	checkState(boolean expression, String message) Checks the truth of the given expression and throws a customize IllegalStateException if it is false.
static void	checkState(boolean expression, String messageFormat, Object... messageArgs) Checks the truth of the given expression and throws a customize IllegalStateException if it is false.

Methods inherited from class java.lang.Object

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

Method Detail

checkArgument

public static void checkArgument(boolean expression,
                                 String message)

Checks the truth of the given expression and throws a customize IllegalArgumentException if it is false. Intended for doin parameter validation in methods and constructors, e.g.

 0, "count must be positive.")
 
 

Parameters:

expression - the precondition to check involving one ore mor parameters to the calling method or constructor

message - the detail message to be used in the event tha an exception is thrown

Throws:

IllegalArgumentException - if expression is false

checkArgument

public static void checkArgument(boolean expression,
                                 String messageFormat,
                                 Object... messageArgs)

Checks the truth of the given expression and throws a customize IllegalArgumentException if it is false. Intended for doin parameter validation in methods and constructors, e.g.

 0, "count must be positive: %s.", count)
 
 

Parameters:

expression - the precondition to check involving one ore mor parameters to the calling method or constructor

messageFormat - a format string for the detail message to be use in the event that an exception is thrown.

messageArgs - the arguments referenced by the format specifier in the messageFormat

Throws:

IllegalArgumentException - if expression is false

checkNotNull

public static <T> T checkNotNull(T reference,
                                 String message)

Checks that the given object reference is not nullNullPointerException if it is Intended for doing parameter validation in methods and constructors e.g.

Type Parameters:

T - the type of the reference

Parameters:

reference - the object reference to check for being null

message - the detail message to be used in the event tha an exception is thrown

Returns:

reference if not null

Throws:

NullPointerException - if reference is null

checkNotNull

public static <T> T checkNotNull(T reference,
                                 String messageFormat,
                                 Object... messageArgs)

Checks that the given object reference is not nullNullPointerException if it is Intended for doing parameter validation in methods and constructors e.g.

Type Parameters:

T - the type of the reference

Parameters:

reference - the object reference to check for being null

messageFormat - a format string for the detail message to be use in the event that an exception is thrown.

messageArgs - the arguments referenced by the format specifier in the messageFormat

Returns:

reference if not null

Throws:

NullPointerException - if reference is null

checkState

public static void checkState(boolean expression,
                              String message)

Checks the truth of the given expression and throws a customize IllegalStateException if it is false. Intended for doin validation in methods involving the state of the calling instance but not involving parameters of the calling method, e.g.

Parameters:

expression - the precondition to check involving the stat of the calling instance

message - the detail message to be used in the event tha an exception is thrown

Throws:

IllegalStateException - if expression is false

checkState

public static void checkState(boolean expression,
                              String messageFormat,
                              Object... messageArgs)

Checks the truth of the given expression and throws a customize IllegalStateException if it is false. Intended for doin validation in methods involving the state of the calling instance but not involving parameters of the calling method, e.g.

Parameters:

expression - the precondition to check involving the stat of the calling instance

messageFormat - a format string for the detail message to be use in the event that an exception is thrown.

messageArgs - the arguments referenced by the format specifier in the messageFormat

Throws:

IllegalStateException - if expression is false

checkNotBlank

public static String checkNotBlank(String str,
                                   String message)

Checks that the given string is not blank and throws a customize NullPointerException if it is null, and a customize IllegalArgumentException if it is empty or whitespace Intended for doing parameter validation in methods and constructors e.g.

Parameters:

str - the string to check for being blank

message - the detail message to be used in the event tha an exception is thrown

Returns:

str if not null

Throws:

NullPointerException - if str is null

IllegalArgumentException - if str is empty or whitespace

checkNotBlank

public static String checkNotBlank(String str,
                                   String messageFormat,
                                   Object... messageArgs)

Checks that the given string is not blank and throws a customize NullPointerException if it is null, and a customize IllegalArgumentException if it is empty or whitespace Intended for doing parameter validation in methods and constructors e.g.

Parameters:

str - the string to check for being blank

messageFormat - a format string for the detail message to be use in the event that an exception is thrown.

messageArgs - the arguments referenced by the format specifier in the messageFormat

Returns:

str if not null

Throws:

NullPointerException - if str is null

IllegalArgumentException - if str is empty or whitespace