public final class Preconditions extends Object
| Modifier and Type | Method and Description |
|---|---|
static void |
checkArgument(boolean expression,
String message)
Checks the truth of the given expression and throws a customized
IllegalArgumentException if it is false. |
static void |
checkArgument(boolean expression,
String messageFormat,
Object... messageArgs)
Checks the truth of the given expression and throws a customized
IllegalArgumentException if it is false. |
static String |
checkNotBlank(String str,
String message)
Checks that the given string is not blank and throws a customized
NullPointerException if it is null, and a customized
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 customized
NullPointerException if it is null, and a customized
IllegalArgumentException if it is empty or whitespace. |
static <T> T |
checkNotNull(T reference,
String message)
Checks that the given object reference is not
null
and throws a customized NullPointerException if it is. |
static <T> T |
checkNotNull(T reference,
String messageFormat,
Object... messageArgs)
Checks that the given object reference is not
null
and throws a customized NullPointerException if it is. |
static void |
checkState(boolean expression,
String message)
Checks the truth of the given expression and throws a customized
IllegalStateException if it is false. |
static void |
checkState(boolean expression,
String messageFormat,
Object... messageArgs)
Checks the truth of the given expression and throws a customized
IllegalStateException if it is false. |
public static void checkArgument(boolean expression,
String message)
IllegalArgumentException if it is false. Intended for doing
parameter validation in methods and constructors, e.g.:
public void foo(int count) {
Preconditions.checkArgument(count > 0, "count must be positive.");
}
expression - the precondition to check involving one ore more
parameters to the calling method or constructormessage - the detail message to be used in the event that
an exception is thrownIllegalArgumentException - if expression is falsepublic static void checkArgument(boolean expression,
String messageFormat,
Object... messageArgs)
IllegalArgumentException if it is false. Intended for doing
parameter validation in methods and constructors, e.g.:
public void foo(int count) {
Preconditions.checkArgument(count > 0, "count must be positive: %s.", count);
}
expression - the precondition to check involving one ore more
parameters to the calling method or constructormessageFormat - a format string for the detail message to be used
in the event that an exception is thrown.messageArgs - the arguments referenced by the format specifiers
in the messageFormatIllegalArgumentException - if expression is falsepublic static <T> T checkNotNull(T reference,
String message)
null
and throws a customized NullPointerException if it is.
Intended for doing parameter validation in methods and constructors,
e.g.:
public void foo(Bar bar, Baz baz) {
this.bar = Preconditions.checkNotNull(bar, "bar must not be null.");
Preconditions.checkNotBull(baz, "baz must not be null.");
}
T - the type of the referencereference - the object reference to check for being nullmessage - the detail message to be used in the event that
an exception is thrownreference if not nullNullPointerException - if reference is nullpublic static <T> T checkNotNull(T reference,
String messageFormat,
Object... messageArgs)
null
and throws a customized NullPointerException if it is.
Intended for doing parameter validation in methods and constructors,
e.g.:
public void foo(Bar bar, Baz baz) {
this.bar = Preconditions.checkNotNull(bar, "bar must not be null.");
Preconditions.checkNotBull(baz, "The %s must not be null.", "baz");
}
T - the type of the referencereference - the object reference to check for being nullmessageFormat - a format string for the detail message to be used
in the event that an exception is thrown.messageArgs - the arguments referenced by the format specifiers
in the messageFormatreference if not nullNullPointerException - if reference is nullpublic static void checkState(boolean expression,
String message)
IllegalStateException if it is false. Intended for doing
validation in methods involving the state of the calling instance,
but not involving parameters of the calling method, e.g.:
public void unlock() {
Preconditions.checkState(locked, "Must be locked to be unlocked.");
}
expression - the precondition to check involving the state
of the calling instancemessage - the detail message to be used in the event that
an exception is thrownIllegalStateException - if expression is falsepublic static void checkState(boolean expression,
String messageFormat,
Object... messageArgs)
IllegalStateException if it is false. Intended for doing
validation in methods involving the state of the calling instance,
but not involving parameters of the calling method, e.g.:
public void unlock() {
Preconditions.checkState(locked,
"Must be locked to be unlocked. Most recent lock: %s",
mostRecentLock);
}
expression - the precondition to check involving the state
of the calling instancemessageFormat - a format string for the detail message to be used
in the event that an exception is thrown.messageArgs - the arguments referenced by the format specifiers
in the messageFormatIllegalStateException - if expression is falsepublic static String checkNotBlank(String str, String message)
NullPointerException if it is null, and a customized
IllegalArgumentException if it is empty or whitespace.
Intended for doing parameter validation in methods and constructors,
e.g.:
public void foo(String text) {
checkNotBlank(text, "The text must not be null, empty or whitespace.");
}
str - the string to check for being blankmessage - the detail message to be used in the event that
an exception is thrownstr if not nullNullPointerException - if str is nullIllegalArgumentException - if str is empty or whitespacepublic static String checkNotBlank(String str, String messageFormat, Object... messageArgs)
NullPointerException if it is null, and a customized
IllegalArgumentException if it is empty or whitespace.
Intended for doing parameter validation in methods and constructors,
e.g.:
public void foo(String text, String id) {
checkNotBlank(
text,
"The text for %s must not be null, empty or whitespace.",
id);
}
str - the string to check for being blankmessageFormat - a format string for the detail message to be used
in the event that an exception is thrown.messageArgs - the arguments referenced by the format specifiers
in the messageFormatstr if not nullNullPointerException - if str is nullIllegalArgumentException - if str is empty or whitespaceCopyright © 2009-2014 JGoodies Software GmbH. All Rights Reserved.