Util (Feign Core 13.5 API)

java.lang.Object
- feign.Util

```
public class Util
extends Object
```
Utilities, typically copied in from guava, so as to avoid dependency conflicts.

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`ACCEPT_ENCODING` The HTTP Accept-Encoding header field name.
`static String`	`CONTENT_ENCODING` The HTTP Content-Encoding header field name.
`static String`	`CONTENT_LENGTH` The HTTP Content-Length header field name.
`static String`	`ENCODING_DEFLATE` Value for the Content-Encoding header that indicates that DEFLATE encoding is in use.
`static String`	`ENCODING_GZIP` Value for the Content-Encoding header that indicates that GZIP encoding is in use.
`static Charset`	`ISO_8859_1` ISO-8859-1: ISO Latin Alphabet Number 1 (ISO-LATIN-1).
`static Type`	`MAP_STRING_WILDCARD` Type literal for {@code Map
`static String`	`RETRY_AFTER` The HTTP Retry-After header field name.
`static Charset`	`UTF_8` UTF-8: eight-bit UCS Transformation Format.

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static List<Field>`	`allFields(Class<?> clazz)`
`static Map<String,Collection<String>>`	`caseInsensitiveCopyOf(Map<String,Collection<String>> map)` Copy entire map of string collection.
`static void`	`checkArgument(boolean expression, String errorMessageTemplate, Object... errorMessageArgs)` Copy of `com.google.common.base.Preconditions#checkArgument`.
`static <T> T`	`checkNotNull(T reference, String errorMessageTemplate, Object... errorMessageArgs)` Copy of `com.google.common.base.Preconditions#checkNotNull`.
`static void`	`checkState(boolean expression, String errorMessageTemplate, Object... errorMessageArgs)` Copy of `com.google.common.base.Preconditions#checkState`.
`static String`	`decodeOrDefault(byte[] data, Charset charset, String defaultValue)`
`static String`	`emptyToNull(String string)` Adapted from `com.google.common.base.Strings#emptyToNull`.
`static Object`	`emptyValueOf(Type type)` This returns well known empty values for well-known java types.
`static void`	`ensureClosed(Closeable closeable)`
`static <T extends Enum<?>> T`	`enumForName(Class<T> enumClass, Object object)`
`static String`	`getThreadIdentifier()`
`static boolean`	`isBlank(String value)` If the provided String is null or empty.
`static boolean`	`isDefault(Method method)` Identifies a method as a default instance method.
`static boolean`	`isNotBlank(String value)` If the provided String is not null or empty.
`static <T> T[]`	`removeValues(T[] values, Predicate<T> shouldRemove, Class<T> type)` Removes values from the array that meet the criteria for removal via the supplied `Predicate` value
`static Type`	`resolveLastTypeParameter(Type genericContext, Class<?> supertype)` Deprecated.
`static <T> T[]`	`toArray(Iterable<? extends T> iterable, Class<T> type)` Adapted from `com.google.common.base.Strings#emptyToNull`.
`static byte[]`	`toByteArray(InputStream in)` Adapted from `com.google.common.io.ByteStreams.toByteArray()`.
`static String`	`toString(Reader reader)` Adapted from `com.google.common.io.CharStreams.toString()`.
`static <T> Collection<T>`	`valuesOrEmpty(Map<String,Collection<T>> map, String key)` Returns an unmodifiable collection which may be empty, but is never null.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail
- CONTENT_LENGTH
```
public static final String CONTENT_LENGTH
```
  The HTTP Content-Length header field name.
  
  See Also:
  
  Constant Field Values
- CONTENT_ENCODING
```
public static final String CONTENT_ENCODING
```
  The HTTP Content-Encoding header field name.
  
  See Also:
  
  Constant Field Values
- ACCEPT_ENCODING
```
public static final String ACCEPT_ENCODING
```
  The HTTP Accept-Encoding header field name.
  
  See Also:
  
  Constant Field Values
- RETRY_AFTER
```
public static final String RETRY_AFTER
```
  The HTTP Retry-After header field name.
  
  See Also:
  
  Constant Field Values
- ENCODING_GZIP
```
public static final String ENCODING_GZIP
```
  Value for the Content-Encoding header that indicates that GZIP encoding is in use.
  
  See Also:
  
  Constant Field Values
- ENCODING_DEFLATE
```
public static final String ENCODING_DEFLATE
```
  Value for the Content-Encoding header that indicates that DEFLATE encoding is in use.
  
  See Also:
  
  Constant Field Values
- UTF_8
```
public static final Charset UTF_8
```
  UTF-8: eight-bit UCS Transformation Format.
- ISO_8859_1
```
public static final Charset ISO_8859_1
```
  ISO-8859-1: ISO Latin Alphabet Number 1 (ISO-LATIN-1).
- MAP_STRING_WILDCARD
```
public static final Type MAP_STRING_WILDCARD
```
  Type literal for Map<String, ?>.

Method Detail

checkArgument

public static void checkArgument(boolean expression,
                                 String errorMessageTemplate,
                                 Object... errorMessageArgs)

Copy of com.google.common.base.Preconditions#checkArgument.

checkNotNull

public static <T> T checkNotNull(T reference,
                                 String errorMessageTemplate,
                                 Object... errorMessageArgs)

Copy of com.google.common.base.Preconditions#checkNotNull.

checkState

public static void checkState(boolean expression,
                              String errorMessageTemplate,
                              Object... errorMessageArgs)

Copy of com.google.common.base.Preconditions#checkState.

isDefault
```
public static boolean isDefault(Method method)
```
Identifies a method as a default instance method.

emptyToNull
```
public static String emptyToNull(String string)
```
Adapted from com.google.common.base.Strings#emptyToNull.

removeValues

public static <T> T[] removeValues(T[] values,
                                   Predicate<T> shouldRemove,
                                   Class<T> type)

Removes values from the array that meet the criteria for removal via the supplied Predicate value

toArray

public static <T> T[] toArray(Iterable<? extends T> iterable,
                              Class<T> type)

Adapted from com.google.common.base.Strings#emptyToNull.

valuesOrEmpty

public static <T> Collection<T> valuesOrEmpty(Map<String,Collection<T>> map,
                                              String key)

Returns an unmodifiable collection which may be empty, but is never null.

ensureClosed

public static void ensureClosed(Closeable closeable)

resolveLastTypeParameter

@Deprecated
public static Type resolveLastTypeParameter(Type genericContext,
                                                        Class<?> supertype)
                                                 throws IllegalStateException

Deprecated.

Moved to feign.Types.resolveLastTypeParameter

Throws:: IllegalStateException

emptyValueOf
```
public static Object emptyValueOf(Type type)
```
This returns well known empty values for well-known java types. This returns null for types not in the following list.
- [Bb]oolean
- byte[]
- Collection
- Iterator
- List
- Map
- Set
When decoding HTTP 404 status, you'll need to teach decoders a default empty value for a type. This method cheaply supports typical types by only looking at the raw type (vs type hierarchy). Decorate for sophistication.

toString

public static String toString(Reader reader)
                       throws IOException

Adapted from com.google.common.io.CharStreams.toString().

Throws:: IOException

toByteArray

public static byte[] toByteArray(InputStream in)
                          throws IOException

Adapted from com.google.common.io.ByteStreams.toByteArray().

Throws:: IOException

decodeOrDefault

public static String decodeOrDefault(byte[] data,
                                     Charset charset,
                                     String defaultValue)

isNotBlank
```
public static boolean isNotBlank(String value)
```
If the provided String is not null or empty.

Parameters:

value - to evaluate.

Returns:

true of the value is not null and not empty.

isBlank
```
public static boolean isBlank(String value)
```
If the provided String is null or empty.

Parameters:

value - to evaluate.

Returns:

true if the value is null or empty.

caseInsensitiveCopyOf
```
public static Map<String,Collection<String>> caseInsensitiveCopyOf(Map<String,Collection<String>> map)
```
Copy entire map of string collection.
The copy is unmodifiable map of unmodifiable collections.

Parameters:

map - string collection map

Returns:

copy of the map or an empty map if the map is null.

enumForName

public static <T extends Enum<?>> T enumForName(Class<T> enumClass,
                                                Object object)

allFields

public static List<Field> allFields(Class<?> clazz)

getThreadIdentifier

public static String getThreadIdentifier()

Class Util

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CONTENT_LENGTH

CONTENT_ENCODING

ACCEPT_ENCODING

RETRY_AFTER

ENCODING_GZIP

ENCODING_DEFLATE

UTF_8

ISO_8859_1

MAP_STRING_WILDCARD