ch.trick17.betterchecks.fluent

Class ObjectBaseCheck<T,C extends ObjectBaseCheck<T,C>>

java.lang.Object

ch.trick17.betterchecks.fluent.BaseCheck<C>

ch.trick17.betterchecks.fluent.ObjectBaseCheck<T,C>

Type Parameters:

T - The argument type, defined by the concrete check classes

C - The type of the concrete check class. This parameter is necessary for this base class to define methods that return the check object itself (with the correct static type), which is necessary for the fluent interface of all checks.

Direct Known Subclasses:

CollectionCheck, NumberCheck, ObjectArrayCheck, ObjectCheck, PrimitiveArrayCheck, StringCheck, UrlCheck

@GwtCompatible
public abstract class ObjectBaseCheck<T,C extends ObjectBaseCheck<T,C>>
extends BaseCheck<C>

The base class for all object checks (as opposed to primitive value checks). It manages the state and provides implementations common to all these checks. The state consists of the argument, the argument class and the null-allowed flag plus the state managed by BaseCheck.

Author:

Michael Faes

See Also:

PrimitiveBaseCheck

Field Summary

Fields

Modifier and Type	Field and Description
protected T	arg The argument that is checked.
protected boolean	nullAllowed This flag indicates that null is a valid value for the argument of this check.

Fields inherited from class ch.trick17.betterchecks.fluent.BaseCheck

argName, inverted

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ObjectBaseCheck(T arg)

Method Summary

Modifier and Type	Method and Description
protected C	check(boolean condition, MessageType msgType, Object... msgArgs) A helper method that allows subclasses to perform simple checks conveniently with a one-liner.
protected void	checkNull() Performs the implicit null check that should be done before each check.
protected C	checkWithCause(boolean condition, MessageType msgType, Throwable cause, Object... msgArgs) The same as check(boolean, MessageType, Object...) but with the possibility to define a cause for the exception that is thrown if the check fails.
C	hasClass(Class<?> clazz) Checks that the argument has the given class, throwing an exception otherwise.
protected IntCheck	intPropertyCheck(int property, String propertyName) Creates an int property check for this argument.
C	isEqualTo(Object object) Checks that the argument is equal to the given object, throwing an exception otherwise.
C	isInstanceOf(Class<?> type) Checks that the argument is an instance of the given type, throwing an exception otherwise.
C	isNotNull() Checks that the argument is not null, throwing an exception otherwise.
C	isNullOr() Allow the argument to be null.
C	isSameAs(Object object) Checks that the argument is the same instance as the given object, throwing an exception otherwise.
protected <T1,C1 extends ObjectBaseCheck<T1,C1>> C1	objectPropertyCheck(Class<C1> checkClass, T1 property, String propertyName) Creates an object property check for this argument.

Methods inherited from class ch.trick17.betterchecks.fluent.BaseCheck

checkConversion, me, named, not

Methods inherited from class java.lang.Object

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

Field Detail

arg

protected final T arg

The argument that is checked.

nullAllowed

protected boolean nullAllowed

This flag indicates that null is a valid value for the argument of this check. It is initialized to false and may be set using the isNullOr() modifier.

All checks must respect this flag. If the check(boolean, MessageType, Object...) helper method is used, the condition passed to it must always start with " arg == null ||" to not cause a NullPointerException.

Constructor Detail

ObjectBaseCheck

protected ObjectBaseCheck(T arg)

Method Detail

isNullOr

public final C isNullOr()

Allow the argument to be null. This method modifies all subsequent checks of this check object to not perform the implicit not- null check that is done by default. It should be called before any of the check methods because the checks are performed immediately when a check method is called.

Returns:

This check

isNotNull

public final C isNotNull()

Checks that the argument is not null, throwing an exception otherwise. This check is sensitive to both the isNullOr() and the BaseCheck.not() modifier. If the former is called before this one, this check is redundant. The later however, changes this check to only accept null as a value.

The message type used for exceptions thrown by this method is MessageType.ARG_NULL.

Returns:

This check

Throws:

IllegalArgumentException - if the argument is null

isSameAs

public final C isSameAs(Object object)

Checks that the argument is the same instance as the given object, throwing an exception otherwise. This check probably only makes sense if used together with BaseCheck.not().

The message type used for exceptions thrown by this method is MessageType.ARG_SAME_AS.

Returns:

This check

Throws:

IllegalArgumentException - if the argument is not the same as the given object

isEqualTo

public final C isEqualTo(Object object)

Checks that the argument is equal to the given object, throwing an exception otherwise.

The message type used for exceptions thrown by this method is MessageType.ARG_EQUAL_TO.

Returns:

This check

Throws:

IllegalArgumentException - if the argument is not equal to the given object

isInstanceOf

@GwtIncompatible(value="Class.isAssignableFrom")
public final C isInstanceOf(Class<?> type)

Checks that the argument is an instance of the given type, throwing an exception otherwise. Note that the argument's class may also be a subclass of the given type. To check the exact class, use the hasClass(Class) method.

The message type used for exceptions thrown by this method is MessageType.ARG_INSTANCE_OF.

Parameters:

type - The type the argument should be an instance of

Returns:

This check

Throws:

IllegalArgumentException - if the argument is not an instance of the given type

hasClass

public final C hasClass(Class<?> clazz)

Checks that the argument has the given class, throwing an exception otherwise. Note that this is different from the isInstanceOf(Class) check.

The message type used for exceptions thrown by this method is MessageType.ARG_CLASS.

Parameters:

clazz - The class the argument should have

Returns:

This check

Throws:

IllegalArgumentException - if the argument does not have the given class

check

protected final C check(boolean condition,
                        MessageType msgType,
                        Object... msgArgs)

A helper method that allows subclasses to perform simple checks conveniently with a one-liner. It checks the given condition in the context of this check object's current state. This means:

• First, it performs the (isNullOr-aware) null-check
• Then, it checks if the given condition is true or false respectively, depending on the inverted flag. If the check fails, an IllegalArgumentException is thrown, with a message formatted using the format belonging to the given message type and the given message arguments.
• Then, it resets the inverted flag.
• Finally, it returns this check.

Parameters:

condition - The check condition

msgType - The message type to be used for the exception message thrown if the check fails

msgArgs - The arguments for the exception message

Returns:

This check

checkWithCause

protected final C checkWithCause(boolean condition,
                                 MessageType msgType,
                                 Throwable cause,
                                 Object... msgArgs)

The same as check(boolean, MessageType, Object...) but with the possibility to define a cause for the exception that is thrown if the check fails.

Parameters:

condition - The check condition

msgType - The message type to be used for the exception message thrown if the check fails

cause - The cause for the exception

msgArgs - The arguments for the exception message

Returns:

This check

checkNull

protected final void checkNull()

Performs the implicit null check that should be done before each check. It takes the isNullOr() modifier into account.

This method can be used by check methods if the check can not be implemented using a check(boolean, MessageType, Object...) one-liner.

objectPropertyCheck

protected final <T1,C1 extends ObjectBaseCheck<T1,C1>> C1 objectPropertyCheck(Class<C1> checkClass,
                                                                              T1 property,
                                                                              String propertyName)

Creates an object property check for this argument. An example of an object property check is UrlCheck.hasHostWhich(). It can be used to write something like this:

Check.that(url).hasHostWhich().endsWith(".ch");

This method can only be used to create property checks for object properties (as opposed to primitive properties). The intPropertyCheck(int, String) method can be used to create checks for int checks. Other primitive types are not supported (or needed) yet.

Parameters:

checkClass - The class of the property check

property - The property to be checked

propertyName - The name of the property. This is used to provide meaningful exception messages for property checks

Returns:

A check of the given class for the given property

intPropertyCheck

protected final IntCheck intPropertyCheck(int property,
                                          String propertyName)

Creates an int property check for this argument. An example of an int property check is StringCheck.hasLengthWhich(). It can be used to write something like this:

Check.that(name).hasLengthWhich().isGreaterThan(10);

Parameters:

property - The int property to be checked

propertyName - The name of the property. This is used to provide meaningful exception messages for property checks

Returns:

A check for the given property