Package com.google.api.client.util
Class Preconditions
java.lang.Object
com.google.api.client.util.Preconditions
Simple static methods to be called at the start of your own methods to verify correct arguments
and state.
NOTE: proxy for the Guava implementation of Preconditions
.
- Since:
- 1.14
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic void
checkArgument
(boolean expression) Ensures the truth of an expression involving one or more parameters to the calling method.static void
checkArgument
(boolean expression, Object errorMessage) Ensures the truth of an expression involving one or more parameters to the calling method.static void
checkArgument
(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) Ensures the truth of an expression involving one or more parameters to the calling method.static <T> T
checkNotNull
(T reference) Ensures that an object reference passed as a parameter to the calling method is not null.static <T> T
checkNotNull
(T reference, Object errorMessage) Ensures that an object reference passed as a parameter to the calling method is not null.static <T> T
checkNotNull
(T reference, String errorMessageTemplate, Object... errorMessageArgs) Ensures that an object reference passed as a parameter to the calling method is not null.static void
checkState
(boolean expression) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.static void
checkState
(boolean expression, Object errorMessage) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.static void
checkState
(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.
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Constructor Details
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Preconditions
private Preconditions()
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Method Details
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checkArgument
public static void checkArgument(boolean expression) Ensures the truth of an expression involving one or more parameters to the calling method.- Parameters:
expression
- a boolean expression- Throws:
IllegalArgumentException
- ifexpression
is false
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checkArgument
Ensures the truth of an expression involving one or more parameters to the calling method.- Parameters:
expression
- a boolean expressionerrorMessage
- the exception message to use if the check fails; will be converted to a string usingString.valueOf(Object)
- Throws:
IllegalArgumentException
- ifexpression
is false
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checkArgument
public static void checkArgument(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) Ensures the truth of an expression involving one or more parameters to the calling method.- Parameters:
expression
- a boolean expressionerrorMessageTemplate
- a template for the exception message should the check fail. The message is formed by replacing each%s
placeholder in the template with an argument. These are matched by position - the first%s
getserrorMessageArgs[0]
, etc. Unmatched arguments will be appended to the formatted message in square braces. Unmatched placeholders will be left as-is.errorMessageArgs
- the arguments to be substituted into the message template. Arguments are converted to strings usingString.valueOf(Object)
.- Throws:
IllegalArgumentException
- ifexpression
is falseNullPointerException
- if the check fails and eithererrorMessageTemplate
orerrorMessageArgs
is null (don't let this happen)
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checkState
public static void checkState(boolean expression) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.- Parameters:
expression
- a boolean expression- Throws:
IllegalStateException
- ifexpression
is false
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checkState
Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.- Parameters:
expression
- a boolean expressionerrorMessage
- the exception message to use if the check fails; will be converted to a string usingString.valueOf(Object)
- Throws:
IllegalStateException
- ifexpression
is false
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checkState
public static void checkState(boolean expression, String errorMessageTemplate, Object... errorMessageArgs) Ensures the truth of an expression involving the state of the calling instance, but not involving any parameters to the calling method.- Parameters:
expression
- a boolean expressionerrorMessageTemplate
- a template for the exception message should the check fail. The message is formed by replacing each%s
placeholder in the template with an argument. These are matched by position - the first%s
getserrorMessageArgs[0]
, etc. Unmatched arguments will be appended to the formatted message in square braces. Unmatched placeholders will be left as-is.errorMessageArgs
- the arguments to be substituted into the message template. Arguments are converted to strings usingString.valueOf(Object)
.- Throws:
IllegalStateException
- ifexpression
is falseNullPointerException
- if the check fails and eithererrorMessageTemplate
orerrorMessageArgs
is null (don't let this happen)
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checkNotNull
public static <T> T checkNotNull(T reference) Ensures that an object reference passed as a parameter to the calling method is not null.- Parameters:
reference
- an object reference- Returns:
- the non-null reference that was validated
- Throws:
NullPointerException
- ifreference
is null
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checkNotNull
Ensures that an object reference passed as a parameter to the calling method is not null.- Parameters:
reference
- an object referenceerrorMessage
- the exception message to use if the check fails; will be converted to a string usingString.valueOf(Object)
- Returns:
- the non-null reference that was validated
- Throws:
NullPointerException
- ifreference
is null
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checkNotNull
public static <T> T checkNotNull(T reference, String errorMessageTemplate, Object... errorMessageArgs) Ensures that an object reference passed as a parameter to the calling method is not null.- Parameters:
reference
- an object referenceerrorMessageTemplate
- a template for the exception message should the check fail. The message is formed by replacing each%s
placeholder in the template with an argument. These are matched by position - the first%s
getserrorMessageArgs[0]
, etc. Unmatched arguments will be appended to the formatted message in square braces. Unmatched placeholders will be left as-is.errorMessageArgs
- the arguments to be substituted into the message template. Arguments are converted to strings usingString.valueOf(Object)
.- Returns:
- the non-null reference that was validated
- Throws:
NullPointerException
- ifreference
is null
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