Package brave

Class Tag<I>

java.lang.Object

brave.Tag<I>

Direct Known Subclasses:

ErrorParser

public abstract class Tag<I>
extends Object

This is a centralized type to parse a tag into any variant of a span. This also avoids the clutter of checking null or guarding on exceptions. Here's an example of a potentially expensive tag:

{@code
 SUMMARY_TAG = new Tag("summary") {

Since:

5.11

See Also:

Tags, SpanCustomizer.tag(String, String), MutableSpan.tag(String, String)

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Tag(String key)

Method Summary

Modifier and Type	Method	Description
String	key()
protected String	key(I input)	Overrides the tag key based on the input
protected abstract String	parseValue(I input, TraceContext context)	Override to change what data from the input are parsed into the span modeling it.
void	tag(I input, TraceContext context, MutableSpan span)	Tags the value parsed from the input.
void	tag(I input, TraceContext context, SpanCustomizer span)	Tags the value parsed from the input.
void	tag(I input, ScopedSpan span)	Tags the value parsed from the input.
void	tag(I input, Span span)	Tags the value parsed from the input.
void	tag(I input, SpanCustomizer span)	Tags the value parsed from the input.
String	toString()
protected static String	validateNonEmpty(String label, String value)
String	value(I input, TraceContext context)	Returns the value that would be tagged to the span or null.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Tag

protected Tag(String key)

Since:

5.11

Method Detail

key

public final String key()

parseValue

@Nullable
protected abstract String parseValue(I input,
                                     @Nullable
                                     TraceContext context)

Override to change what data from the input are parsed into the span modeling it. Any exceptions will be logged and ignored.

Note: Overrides of Tags.ERROR must return a valid value when {@param context} is null, even if that value is "" (empty string). Otherwise, error spans will not be marked as such.

Returns:

The result to add as a span tag. null means no tag will be added. Note: empty string is a valid tag value!

Since:

5.11

value

@Nullable
public String value(@Nullable
                    I input,
                    @Nullable
                    TraceContext context)

Returns the value that would be tagged to the span or null.

Since:

5.12

See Also:

key(), parseValue(Object, TraceContext)

key

protected String key(I input)

Overrides the tag key based on the input

tag

public final void tag(I input,
                      ScopedSpan span)

Tags the value parsed from the input.

Since:

5.11

tag

public final void tag(I input,
                      Span span)

Tags the value parsed from the input.

Since:

5.11

tag

public final void tag(I input,
                      @Nullable
                      TraceContext context,
                      SpanCustomizer span)

Tags the value parsed from the input.

Since:

5.11

tag

public final void tag(I input,
                      SpanCustomizer span)

Tags the value parsed from the input.

Since:

5.11

tag

public final void tag(I input,
                      @Nullable
                      TraceContext context,
                      MutableSpan span)

Tags the value parsed from the input.

Since:

5.11

See Also:

SpanHandler.end(TraceContext, MutableSpan, SpanHandler.Cause)

toString

public String toString()

Overrides:

toString in class Object

validateNonEmpty

protected static String validateNonEmpty(String label,
                                         String value)