Class Preconditions

java.lang.Object
com.google.api.client.util.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 Preconditions.

Since:
1.14
  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    private
     
  • Method Summary

    Modifier and Type
    Method
    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.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Constructor Details

    • Preconditions

      private Preconditions()
  • Method Details

    • 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