Package dev.hypera.chameleon.util

Class Preconditions

java.lang.Object

dev.hypera.chameleon.util.Preconditions

public final class Preconditions
extends Object

Preconditions, a set of convenience methods to aid in validating method or constructor invocation.

We use JetBrains Annotations for nullability indication, however this makes everything a lot stricter so that Chameleon does not end up in an illegal state.

Heavily inspired by Google Guava's Preconditions.

Method Summary

Modifier and Type	Method	Description
static void	checkArgument(boolean expression)	Ensures the expression is true to validate an argument.
static void	checkArgument(boolean expression, @NotNull String message)	Ensures the expression is true to validate an argument.
static void	checkArgument(boolean expression, @NotNull String messageFormat, @NotNull Object... messageArgs)	Ensures the expression is true to validate an argument.
static @NotNull String	checkMatches(@NotNull String name, @NotNull Pattern regex, @Nullable String value)	Ensures the given value matches the given pattern.
static <T> @NotNull Collection<T>	checkNoneNull(@NotNull String name, @Nullable Collection<T> value)	Ensures the given value does not contain null.
static <T> T	checkNotNull(@NotNull String name, T value)	Ensures the given value is not null.
static <T> T	checkNotNull(T value)	Ensures the given value is not null.
static @NotNull String	checkNotNullOrEmpty(@NotNull String name, @Nullable String value)	Ensures the given value is not null or empty.
static @NotNull String	checkNotNullOrEmpty(@Nullable String value)	Ensures the given value is not null or empty.
static <T> T	checkNotNullState(@NotNull String name, T value)	Ensures the given value is not null.
static void	checkState(boolean expression)	Ensures that expression is true to validate a state.
static void	checkState(boolean expression, @NotNull String message)	Ensures the expression is true to validate a state.
static void	checkState(boolean expression, @NotNull String messageFormat, @NotNull Object... messageArgs)	Ensures the expression is true to validate a state.

Methods inherited from class java.lang.Object

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

Method Detail

checkArgument

@Contract("false -> fail")
public static void checkArgument(boolean expression)

Ensures the expression is true to validate an argument.

Parameters:

expression - Expression.

Throws:

IllegalArgumentException - if expression is false.

checkArgument

@Contract("false, _ -> fail")
public static void checkArgument(boolean expression,
                                 @NotNull
                                 @NotNull String message)

Ensures the expression is true to validate an argument.

Parameters:

expression - Expression.

message - The exception message to use if check fails.

Throws:

IllegalArgumentException - if expression is false.

checkArgument

@Contract("false, _, _ -> fail")
public static void checkArgument(boolean expression,
                                 @NotNull
                                 @NotNull String messageFormat,
                                 @NotNull
                                 @NotNull Object... messageArgs)

Ensures the expression is true to validate an argument.

Parameters:

expression - Expression.

messageFormat - The exception message format to use if check fails.

messageArgs - The arguments to use with the message format if the check fails.

Throws:

IllegalArgumentException - if expression is false.

checkState

@Contract("false -> fail")
public static void checkState(boolean expression)

Ensures that expression is true to validate a state.

Parameters:

expression - Expression.

Throws:

IllegalStateException - if expression is false.

checkState

@Contract("false, _ -> fail")
public static void checkState(boolean expression,
                              @NotNull
                              @NotNull String message)

Ensures the expression is true to validate a state.

Parameters:

expression - Expression.

message - The exception message to use if check fails.

Throws:

IllegalStateException - if expression is false.

checkState

@Contract("false, _, _ -> fail")
public static void checkState(boolean expression,
                              @NotNull
                              @NotNull String messageFormat,
                              @NotNull
                              @NotNull Object... messageArgs)

Ensures the expression is true to validate a state.

Parameters:

expression - Expression.

messageFormat - The exception message format to use if check fails.

messageArgs - The arguments to use with the message format if the check fails.

Throws:

IllegalStateException - if expression is false.

checkNotNull

@Contract("!null -> param1; null -> fail")
@NotNull
public static <T> T checkNotNull(@Nullable
                                 T value)

Ensures the given value is not null.

Type Parameters:

T - Value type.

Parameters:

value - Argument value.

Returns:

value

Throws:

NullPointerException - if value is null.

checkNotNull

@Contract("_, !null -> param2; _, null -> fail")
@NotNull
public static <T> T checkNotNull(@NotNull
                                 @NotNull String name,
                                 @Nullable
                                 T value)

Ensures the given value is not null.

Type Parameters:

T - Value type.

Parameters:

name - Argument name, used in the exception message if value is null.

value - Argument value.

Returns:

value.

Throws:

IllegalArgumentException - if value is null.

checkNotNullState

@Contract("_, !null -> param2; _, null -> fail")
@NotNull
public static <T> T checkNotNullState(@NotNull
                                      @NotNull String name,
                                      @Nullable
                                      T value)

Ensures the given value is not null.

Type Parameters:

T - Value type.

Parameters:

name - Argument name, used in the exception message if value is null.

value - Argument value.

Returns:

value.

Throws:

IllegalStateException - if value is null.

checkNotNullOrEmpty

@Contract("!null -> param1; null -> fail")
@NotNull
public static @NotNull String checkNotNullOrEmpty(@Nullable
                                                  @Nullable String value)

Ensures the given value is not null or empty.

Parameters:

value - Argument value.

Returns:

value.

Throws:

IllegalArgumentException - if value is null or empty.

checkNotNullOrEmpty

@Contract("_, !null -> param2; _, null -> fail")
@NotNull
public static @NotNull String checkNotNullOrEmpty(@NotNull
                                                  @NotNull String name,
                                                  @Nullable
                                                  @Nullable String value)

Ensures the given value is not null or empty.

Parameters:

name - Argument name.

value - Argument value.

Returns:

value.

Throws:

IllegalArgumentException - if value is null or empty.

checkNoneNull

@Contract("_, !null -> param2; _, null -> fail")
@NotNull
public static <T> @NotNull Collection<T> checkNoneNull(@NotNull
                                                       @NotNull String name,
                                                       @Nullable
                                                       @Nullable Collection<T> value)

Ensures the given value does not contain null.

Type Parameters:

T - Value type.

Parameters:

name - Argument name, used in the exception message if value contains null.

value - Argument value.

Returns:

value.

Throws:

IllegalArgumentException - if value contains null.

checkMatches

@Contract("_, _, null -> fail; _, _, _ -> param3")
@NotNull
public static @NotNull String checkMatches(@NotNull
                                           @NotNull String name,
                                           @NotNull
                                           @NotNull Pattern regex,
                                           @Nullable
                                           @Nullable String value)

Ensures the given value matches the given pattern.

Parameters:

name - Argument name.

regex - RegEx pattern to match against.

value - Argument value.

Returns:

value.

Throws:

IllegalArgumentException - if the given value does not match the given pattern.