java.lang.Object
- io.spine.logging.flogger.context.Tags

```
public final class Tags
extends Object
```
Immutable tags which can be attached to log statements via platform specific injection mechanisms.
A tag is either a "simple" tag, added via Tags.Builder.addTag(String) or a tag with a value, added via one of the addTag(name,value) methods. When thinking of tags as a Map<String, Set<Object>>, the value of a "simple" tag is the empty set.
Tag values can be of several simple types and are held in a stable, sorted order within a Tags instance. In other words it never matters in which order two Tags instances are merged.
When tags are merged, the result is the union of the values. This is easier to explain When thinking of tags as a Map<String, Set<Object>>, where "merging" means taking the union of the Set associated with the tag name. In particular, for a given tag name:
- Adding the same value for a given tag twice has no additional effect.
- Adding a simple tag twice has no additional effect.
- Adding a tag with a value is also implicitly like adding a simple tag with the same name.
The toString() implementation of this class provides a human readable, machine parsable representation of the tags.
See Also:

Original Java code of Google Flogger

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class Tags.Builder
A mutable builder for tags.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Map<String,Set<Object>>`	`asMap()`	Returns an immutable map containing the tag values.
`static Tags.Builder`	`builder()`	Returns a new builder for adding tags.
`static Tags`	`empty()`	Returns the immutable empty tags instance.
`boolean`	`equals(@Nullable Object obj)`
`int`	`hashCode()`
`boolean`	`isEmpty()`	Returns whether this instance is empty.
`Tags`	`merge(Tags other)`	Merges two tags instances, combining values for any name contained in both.
`static Tags`	`of(String name, boolean value)`	Returns a single tag without needing to use the builder API.
`static Tags`	`of(String name, double value)`	Returns a single tag without needing to use the builder API.
`static Tags`	`of(String name, long value)`	Returns a single tag without needing to use the builder API.
`static Tags`	`of(String name, String value)`	Returns a single tag without needing to use the builder API.
`String`	`toString()`	Returns human readable representation of the tags.

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

- Method Detail
  - builder
```
public static Tags.Builder builder()
```
    Returns a new builder for adding tags.
  - empty
```
public static Tags empty()
```
    Returns the immutable empty tags instance.
  - of
```
public static Tags of(String name,
                      String value)
```
    Returns a single tag without needing to use the builder API. Where multiple tags are needed, it is always better to use the builder directly.
  - of
```
public static Tags of(String name,
                      boolean value)
```
    Returns a single tag without needing to use the builder API. Where multiple tags are needed, it is always better to use the builder directly.
  - of
```
public static Tags of(String name,
                      long value)
```
    Returns a single tag without needing to use the builder API. Where multiple tags are needed, it is always better to use the builder directly.
  - of
```
public static Tags of(String name,
                      double value)
```
    Returns a single tag without needing to use the builder API. Where multiple tags are needed, it is always better to use the builder directly.
  - asMap
```
public Map<String,Set<Object>> asMap()
```
    Returns an immutable map containing the tag values.
  - isEmpty
```
public boolean isEmpty()
```
    Returns whether this instance is empty.
  - merge
```
public Tags merge(Tags other)
```
    Merges two tags instances, combining values for any name contained in both.
  - equals
```
public boolean equals(@Nullable Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Returns human readable representation of the tags. This is not a stable representation and may change over time. If you need to format tags reliably for logging, you should not rely on this method.
    
    Overrides:
    
    toString in class Object

Class Tags

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

builder

empty

of

of

of

of

asMap

isEmpty

merge

equals

hashCode

toString