com.google.api.client.util

Class Preconditions


  • public final class Preconditions
extends Object
    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 com.google.common.base.Preconditions.

    Since:
    1.14

    • Method Summary

      Methods

      Modifier and Type Method and Description
      static 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.

    • Method Detail

      • 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 - if expression is false

      • checkArgument

        public static void checkArgument(boolean expression,
                                 Object errorMessage)
        Ensures the truth of an expression involving one or more parameters to the calling method.
        Parameters:
        expression - a boolean expression
        errorMessage - the exception message to use if the check fails; will be converted to a string using String.valueOf(Object)
        Throws:
        IllegalArgumentException - if expression is false

      • 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 expression
        errorMessageTemplate - 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 gets errorMessageArgs[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 using String.valueOf(Object).
        Throws:
        IllegalArgumentException - if expression is false
        NullPointerException - if the check fails and either errorMessageTemplate or errorMessageArgs is null (don't let this happen)

      • 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 - if expression is false

      • checkState

        public 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.
        Parameters:
        expression - a boolean expression
        errorMessage - the exception message to use if the check fails; will be converted to a string using String.valueOf(Object)
        Throws:
        IllegalStateException - if expression is false

      • 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 expression
        errorMessageTemplate - 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 gets errorMessageArgs[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 using String.valueOf(Object).
        Throws:
        IllegalStateException - if expression is false
        NullPointerException - if the check fails and either errorMessageTemplate or errorMessageArgs is null (don't let this happen)

      • 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 - if reference is null

      • checkNotNull

        public static <T> T checkNotNull(T reference,
                                 Object errorMessage)
        Ensures that an object reference passed as a parameter to the calling method is not null.
        Parameters:
        reference - an object reference
        errorMessage - the exception message to use if the check fails; will be converted to a string using String.valueOf(Object)
        Returns:
        the non-null reference that was validated
        Throws:
        NullPointerException - if reference is null

      • 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 reference
        errorMessageTemplate - 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 gets errorMessageArgs[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 using String.valueOf(Object).
        Returns:
        the non-null reference that was validated
        Throws:
        NullPointerException - if reference is null