randoop.contract

Class IsNull

java.lang.Object

randoop.contract.ObjectContract

randoop.contract.IsNull

public final class IsNull
extends ObjectContract

The contract: x == null.

Obviously, this is not a property that must hold of all objects in a test. Randoop creates an instance of this contract when, during execution of a sequence, it determines that the above property holds. The property thus represents a regression as it captures the behavior of the code when it is executed.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static TypeTuple	inputTypes The arguments to which this contract can be applied.

Constructor Summary

Constructors

Constructor and Description
IsNull()

Method Summary

Modifier and Type	Method and Description
boolean	equals(@Nullable java.lang.Object o)
boolean	evaluate(java.lang.Object... objects) Evaluates the contract on the given values.
java.lang.String	get_observer_str() Returns a string describing the observer.
int	getArity() The number of values that this contract is over.
TypeTuple	getInputTypes() Returns the input types for this contract.
int	hashCode()
java.lang.String	toCodeString() A string that can be used as Java source code and will result in the expression being evaluated.
java.lang.String	toCommentString() A string that will be inserted as a comment in the test before the code corresponding to this contract.

Methods inherited from class randoop.contract.ObjectContract

checkContract, failedContract, toStringHandleExceptions

Methods inherited from class java.lang.Object

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

Field Detail

inputTypes

static TypeTuple inputTypes

The arguments to which this contract can be applied.

Constructor Detail

IsNull

public IsNull()

Method Detail

equals

public boolean equals(@Nullable java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

evaluate

public boolean evaluate(java.lang.Object... objects)
                 throws java.lang.Throwable

Description copied from class: ObjectContract

Evaluates the contract on the given values. Returns false if the contract was violated. Returns true if the contract was satisfied or was not applicable.

When calling this method during execution of a test, Randoop guarantees that objects does not contain any null objects, and that objects.length == getArity().

Specified by:

evaluate in class ObjectContract

Parameters:

objects - the actual parameters to this contract

Returns:

false if the contract is violated, true otherwise

Throws:

java.lang.Throwable - if an exception is thrown in evaluation

getArity

public int getArity()

Description copied from class: ObjectContract

The number of values that this contract is over.

Specified by:

getArity in class ObjectContract

Returns:

the number of arguments to the contract

getInputTypes

public TypeTuple getInputTypes()

Description copied from class: ObjectContract

Returns the input types for this contract.

Specified by:

getInputTypes in class ObjectContract

Returns:

the input types for this contract

toCodeString

public java.lang.String toCodeString()

Description copied from class: ObjectContract

A string that can be used as Java source code and will result in the expression being evaluated.

The N-th object that participates in the contract check should be referred to as "xN" (for N one of 0, ... , 9). For example, if the expression of arity 2 represents a call of the equals method between two objects, the code should be something like assert x0.equals(x1);".

The string does not contain a trailing newline. When there is a leading comment, it should start with a newline.

Specified by:

toCodeString in class ObjectContract

Returns:

the code string representation of this contract; must be non-null

toCommentString

public java.lang.String toCommentString()

Description copied from class: ObjectContract

A string that will be inserted as a comment in the test before the code corresponding to this contract. Occurrences of variables x0, x1, x2, etc. in the string will be replaced by actual values.

Specified by:

toCommentString in class ObjectContract

Returns:

the comment string representation of this contract

get_observer_str

public java.lang.String get_observer_str()

Description copied from class: ObjectContract

Returns a string describing the observer.

Specified by:

get_observer_str in class ObjectContract

Returns:

a string description of the contract