Useful for identifying programmer errors early and clearly at runtime.
For example, if the contract of a public method states it does not allow
null arguments, Assert can be used to validate that contract.
Doing this clearly indicates a contract violation when it occurs and protects
the class's invariants.
Typically used to validate method arguments rather than configuration properties, to check for cases that are usually programmer errors rather than configuration errors. In contrast to configuration initialization code, there is usually no point in falling back to defaults in such methods.
This class is similar to JUnit's assertion library. If an argument value is
deemed invalid, an IllegalArgumentException is thrown (typically).
For example:
Assert.notNull(clazz, "The class must not be null"); Assert.isTrue(i > 0, "The value must be greater than zero");
Mainly for internal use within the framework; for a more comprehensive suite
of assertion utilities consider org.apache.commons.lang3.Validate
from Apache Commons
Lang, Google Guava's Preconditions,
or similar third-party libraries.
| Access | Constructor and Description |
|---|---|
| private |
| Modifier and Type | Method and Description |
|---|---|
| public static void | |
| public static void | |
| public static void |
| Assert | back to summary |
|---|---|
| private Assert() | |
| isTrue | back to summary |
|---|---|
| public static void isTrue(boolean expression, String message) Assert a boolean expression, throwing an Assert.isTrue(i > 0, "The value must be greater than zero");
| |
| notNull | back to summary |
|---|---|
| public static void notNull(Object object, String message) Assert that an object is not Assert.notNull(clazz, "The class must not be null");
| |
| state | back to summary |
|---|---|
| public static void state(boolean expression, String message) Assert a boolean expression, throwing an Assert.state(id == null, "The id property must not already be initialized");
| |