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java.lang.Objectcom.google.gwt.inject.rebind.util.Preconditions
public final class Preconditions
Simple static methods to be called at the start of your own methods to verify correct arguments and state. This allows constructs such as
     if (count <= 0) {
       throw new IllegalArgumentException("must be positive: " + count);
     }
 to be replaced with the more compact
 
     checkArgument(count > 0, "must be positive: %s", count);
 Note that the sense of the expression is inverted; with Preconditions
 you declare what you expect to be true, just as you do with an
 
 assert or a JUnit assertTrue call.
 Warning: only the "%s" specifier is recognized as a
 placeholder in these messages, not the full range of String.format(String, Object[]) specifiers.
 
Take care not to confuse precondition checking with other similar types
 of checks! Precondition exceptions -- including those provided here, but also
 IndexOutOfBoundsException, UnsupportedOperationException and others -- are used to signal that the
 calling method has made an error. This tells the caller that it should
 not have invoked the method when it did, with the arguments it did, or
 perhaps ever. Postcondition or other invariant failures should not throw
 these types of exceptions.
 
 
This class was adapted from google-collections project.
| Method Summary | ||
|---|---|---|
| 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,
              java.lang.Object errorMessage)Ensures the truth of an expression involving one or more parameters to the calling method. | |
| static void | checkArgument(boolean expression,
              java.lang.String errorMessageTemplate,
              java.lang.Object... errorMessageArgs)Ensures the truth of an expression involving one or more parameters to the calling method. | |
| static int | checkElementIndex(int index,
                  int size)Ensures that indexspecifies a valid element in an array,
 list or string of sizesize. | |
| static int | checkElementIndex(int index,
                  int size,
                  java.lang.String desc)Ensures that indexspecifies a valid element in an array,
 list or string of sizesize. | |
| static
 | checkNotNull(T reference)Ensures that an object reference passed as a parameter to the calling method is not null. | |
| static
 | checkNotNull(T reference,
             java.lang.Object errorMessage)Ensures that an object reference passed as a parameter to the calling method is not null. | |
| static
 | checkNotNull(T reference,
             java.lang.String errorMessageTemplate,
             java.lang.Object... errorMessageArgs)Ensures that an object reference passed as a parameter to the calling method is not null. | |
| static int | checkPositionIndex(int index,
                   int size)Ensures that indexspecifies a valid position in an array,
 list or string of sizesize. | |
| static int | checkPositionIndex(int index,
                   int size,
                   java.lang.String desc)Ensures that indexspecifies a valid position in an array,
 list or string of sizesize. | |
| static void | checkPositionIndexes(int start,
                     int end,
                     int size)Ensures that startandendspecify a valid positions
 in an array, list or string of sizesize, and are in order. | |
| 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,
           java.lang.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,
           java.lang.String errorMessageTemplate,
           java.lang.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 | 
| Method Detail | 
|---|
public static void checkArgument(boolean expression)
expression - a boolean expression
java.lang.IllegalArgumentException - if expression is false
public static void checkArgument(boolean expression,
                                 java.lang.Object errorMessage)
expression - a boolean expressionerrorMessage - the exception message to use if the check fails; will
     be converted to a string using String.valueOf(Object)
java.lang.IllegalArgumentException - if expression is false
public static void checkArgument(boolean expression,
                                 java.lang.String errorMessageTemplate,
                                 java.lang.Object... errorMessageArgs)
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 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).
java.lang.IllegalArgumentException - if expression is false
java.lang.NullPointerException - if the check fails and either errorMessageTemplate or errorMessageArgs is null (don't let
     this happen)
public static int checkElementIndex(int index,
                                    int size)
index specifies a valid element in an array,
 list or string of size size. An element index may range from zero,
 inclusive, to size, exclusive.
index - a user-supplied index identifying an element of an array, list
     or stringsize - the size of that array, list or string
index
java.lang.IndexOutOfBoundsException - if index is negative or is not
     less than size
java.lang.IllegalArgumentException - if size is negative
public static int checkElementIndex(int index,
                                    int size,
                                    java.lang.String desc)
index specifies a valid element in an array,
 list or string of size size. An element index may range from zero,
 inclusive, to size, exclusive.
index - a user-supplied index identifying an element of an array, list
     or stringsize - the size of that array, list or stringdesc - the text to use to describe this index in an error message
index
java.lang.IndexOutOfBoundsException - if index is negative or is not
     less than size
java.lang.IllegalArgumentException - if size is negativepublic static <T> T checkNotNull(T reference)
reference - an object reference
java.lang.NullPointerException - if reference is null
public static <T> T checkNotNull(T reference,
                                 java.lang.Object errorMessage)
reference - an object referenceerrorMessage - the exception message to use if the check fails; will
     be converted to a string using String.valueOf(Object)
java.lang.NullPointerException - if reference is null
public static <T> T checkNotNull(T reference,
                                 java.lang.String errorMessageTemplate,
                                 java.lang.Object... errorMessageArgs)
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 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).
java.lang.NullPointerException - if reference is null
public static int checkPositionIndex(int index,
                                     int size)
index specifies a valid position in an array,
 list or string of size size. A position index may range from zero
 to size, inclusive.
index - a user-supplied index identifying a position in an array, list
     or stringsize - the size of that array, list or string
index
java.lang.IndexOutOfBoundsException - if index is negative or is
     greater than size
java.lang.IllegalArgumentException - if size is negative
public static int checkPositionIndex(int index,
                                     int size,
                                     java.lang.String desc)
index specifies a valid position in an array,
 list or string of size size. A position index may range from zero
 to size, inclusive.
index - a user-supplied index identifying a position in an array, list
     or stringsize - the size of that array, list or stringdesc - the text to use to describe this index in an error message
index
java.lang.IndexOutOfBoundsException - if index is negative or is
     greater than size
java.lang.IllegalArgumentException - if size is negative
public static void checkPositionIndexes(int start,
                                        int end,
                                        int size)
start and end specify a valid positions
 in an array, list or string of size size, and are in order. A
 position index may range from zero to size, inclusive.
start - a user-supplied index identifying a starting position in an
     array, list or stringend - a user-supplied index identifying a ending position in an array,
     list or stringsize - the size of that array, list or string
java.lang.IndexOutOfBoundsException - if either index is negative or is
     greater than size, or if end is less than start
java.lang.IllegalArgumentException - if size is negativepublic static void checkState(boolean expression)
expression - a boolean expression
java.lang.IllegalStateException - if expression is false
public static void checkState(boolean expression,
                              java.lang.Object errorMessage)
expression - a boolean expressionerrorMessage - the exception message to use if the check fails; will
     be converted to a string using String.valueOf(Object)
java.lang.IllegalStateException - if expression is false
public static void checkState(boolean expression,
                              java.lang.String errorMessageTemplate,
                              java.lang.Object... errorMessageArgs)
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 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).
java.lang.IllegalStateException - if expression is false
java.lang.NullPointerException - if the check fails and either errorMessageTemplate or errorMessageArgs is null (don't let
     this happen)| 
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