Package com.thebuzzmedia.exiftool.commons.lang

Class PreConditions

java.lang.Object

com.thebuzzmedia.exiftool.commons.lang.PreConditions

public final class PreConditions
extends Object

Static PreConditions Utilities.

Method Summary

Modifier and Type	Method	Description
static <T extends Number> T	isPositive(T nb, String message, Object... params)	Check if given number is strictly positive (strictly greater than zero).
static File	isReadable(File file, String message, Object... params)	Check that a given file exist and is readable.
static File	isWritable(File file, String message, Object... params)	Check that a given file exist and is writable.
static String	notBlank(String val, String message, Object... params)	Ensures that a string is: Not null. Not empty. Not blank (i.e contains at least one character other than space).
static <T> Iterable<T>	notEmpty(Iterable<T> val, String message, Object... params)	Ensures that iterable element is: Not null. Not empty.
static <T,U> Map<T,U>	notEmpty(Map<T,U> val, String message, Object... params)	Ensures that map is: Not null. Not empty.
static <T> T[]	notEmpty(T[] val, String message, Object... params)	Ensures that array is: Not null. Not empty.
static <T> T	notNull(T val, String message, Object... params)	Ensures that an object reference passed as a parameter to the calling method is not null.

Methods inherited from class java.lang.Object

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

Method Detail

notNull

public static <T> T notNull(T val,
                            String message,
                            Object... params)

Ensures that an object reference passed as a parameter to the calling method is not null.

Type Parameters:

T - Type of parameter.

Parameters:

val - Value to check.

message - Message passed to NullPointerException.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original value if it is not null.

Throws:

NullPointerException - If val is null.

notBlank

public static String notBlank(String val,
                              String message,
                              Object... params)

Ensures that a string is:

• Not null.
• Not empty.
• Not blank (i.e contains at least one character other than space).

Parameters:

val - Value to check.

message - Message passed to thrown exception.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original value if it is not null.

Throws:

NullPointerException - If val is null.

IllegalArgumentException - If val is empty or blank.

notEmpty

public static <T> T[] notEmpty(T[] val,
                               String message,
                               Object... params)

Ensures that array is:

• Not null.
• Not empty.

Type Parameters:

T - Type of elements in array.

Parameters:

val - Value to check.

message - Message passed to thrown exception.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original value if it is not empty.

Throws:

NullPointerException - If val is null.

IllegalArgumentException - If val is empty.

notEmpty

public static <T,U> Map<T,U> notEmpty(Map<T,U> val,
                                                  String message,
                                                  Object... params)

Ensures that map is:

• Not null.
• Not empty.

Type Parameters:

T - Type of keys in map.

U - Type of values in map.

Parameters:

val - Value to check.

message - Message passed to thrown exception.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original value if it is not empty.

Throws:

NullPointerException - If val is null.

IllegalArgumentException - If val is empty.

notEmpty

public static <T> Iterable<T> notEmpty(Iterable<T> val,
                                       String message,
                                       Object... params)

Ensures that iterable element is:

• Not null.
• Not empty.

Type Parameters:

T - Type of elements in iterable structure.

Parameters:

val - Value to check.

message - Message passed to thrown exception.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original value if it is not empty.

Throws:

NullPointerException - If val is null.

IllegalArgumentException - If val is empty.

isPositive

public static <T extends Number> T isPositive(T nb,
                                              String message,
                                              Object... params)

Check if given number is strictly positive (strictly greater than zero).

Type Parameters:

T - Type of number.

Parameters:

nb - Number.

message - Error message.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original number.

Throws:

NullPointerException - If nb is null.

IllegalArgumentException - If nb is less than or equal to zero.

isReadable

public static File isReadable(File file,
                              String message,
                              Object... params)

Check that a given file exist and is readable.

Parameters:

file - File to check.

message - Error message.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original file.

Throws:

NullPointerException - If file is null.

UnreadableFileException - If file does not exist.

UnreadableFileException - If file cannot be read.

isWritable

public static File isWritable(File file,
                              String message,
                              Object... params)

Check that a given file exist and is writable.

Parameters:

file - File to check.

message - Error message.

params - Message parameters (formatted with String.format(String, Object...)).

Returns:

Original file.

Throws:

NullPointerException - If file is null.

UnreadableFileException - If file does not exist.

UnreadableFileException - If file cannot be updated.