Class Assert
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 {link 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.
- Since:
- 1.1.2
- Author:
- Keith Donald, Juergen Hoeller, Sam Brannen, Colin Sampaleanu, Rob Harrop
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionstatic void
Assert a boolean expression, throwing anIllegalArgumentException
if the expression evaluates tofalse
.static void
Assert that an object is notnull
.static void
Assert a boolean expression, throwing anIllegalStateException
if the expression evaluates tofalse
.
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Constructor Details
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Assert
public Assert()
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Method Details
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state
Assert a boolean expression, throwing anIllegalStateException
if the expression evaluates tofalse
.Call {link #isTrue} if you wish to throw an
IllegalArgumentException
on an assertion failure.Assert.state(id == null, "The id property must not already be initialized");
- Parameters:
expression
- a boolean expressionmessage
- the exception message to use if the assertion fails- Throws:
IllegalStateException
- ifexpression
isfalse
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isTrue
Assert a boolean expression, throwing anIllegalArgumentException
if the expression evaluates tofalse
.Assert.isTrue(i > 0, "The value must be greater than zero");
- Parameters:
expression
- a boolean expressionmessage
- the exception message to use if the assertion fails- Throws:
IllegalArgumentException
- ifexpression
isfalse
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notNull
Assert that an object is notnull
.Assert.notNull(clazz, "The class must not be null");
- Parameters:
object
- the object to checkmessage
- the exception message to use if the assertion fails- Throws:
IllegalArgumentException
- if the object isnull
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