unhacks and adds note about thing to do

Author: Adrian Cole

src/main/java/brave/opentracing/BraveSpanBuilder.java

@@ -90,8 +90,16 @@ public final class BraveSpanBuilder implements Tracer.SpanBuilder {
   }
 
   @Override public <T> BraveSpanBuilder withTag(Tag<T> tag, T value) {
-    new TagSetterHack<>(this, tag, value);
-    return this;
+    if (tag == null) throw new NullPointerException("tag == null");
+    if (value == null) throw new NullPointerException("value == null");
+    if (value instanceof String) {
+      return withTag(tag.getKey(), (String) value);
+    } else if (value instanceof Number) {
+      return withTag(tag.getKey(), (Number) value);
+    } else if (value instanceof Boolean) {
+      return withTag(tag.getKey(), (Boolean) value);
+    }
+    throw new IllegalArgumentException("value must be a string, number or boolean");
   }
 
   @Override public BraveSpanBuilder withStartTimestamp(long microseconds) {
@@ -173,78 +181,4 @@ public final class BraveSpanBuilder implements Tracer.SpanBuilder {
 
     return result;
   }
-
-  static class TagSetterHack<T> implements Span {
-    static final String ERROR_FORMAT = "%s.set(span, %s) should only call Span.setTag";
-
-    final Tracer.SpanBuilder delegate;
-    final Tag<T> tag;
-    final T value;
-
-    TagSetterHack(Tracer.SpanBuilder delegate, Tag<T> tag, T value) {
-      this.delegate = delegate;
-      this.tag = tag;
-      this.value = value;
-    }
-
-    @Override public SpanContext context() {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public Span setTag(String key, String value) {
-      delegate.withTag(key, value);
-      return this;
-    }
-
-    @Override public Span setTag(String key, boolean value) {
-      delegate.withTag(key, value);
-      return this;
-    }
-
-    @Override public Span setTag(String key, Number value) {
-      delegate.withTag(key, value);
-      return this;
-    }
-
-    @Override public <T2> Span setTag(Tag<T2> tag, T2 value) {
-      delegate.withTag(tag, value);
-      return this;
-    }
-
-    @Override public Span log(Map<String, ?> fields) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public Span log(long timestampMicroseconds, Map<String, ?> fields) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public Span log(String event) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public Span log(long timestampMicroseconds, String event) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public Span setBaggageItem(String key, String value) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public String getBaggageItem(String key) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public Span setOperationName(String operationName) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public void finish() {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-
-    @Override public void finish(long finishMicros) {
-      throw new IllegalArgumentException(String.format(ERROR_FORMAT, tag, value));
-    }
-  }
 }

src/main/java/brave/opentracing/BraveTracer.java

@@ -92,6 +92,7 @@ public static final class Builder {
       if (tracing == null) throw new NullPointerException("brave tracing component == null");
       this.tracing = tracing;
       formatToPropagation.put(Format.Builtin.HTTP_HEADERS, tracing.propagation());
+      // TODO: TEXT_MAP_INJECT and TEXT_MAP_EXTRACT (not excited about this)
       formatToPropagation.put(Format.Builtin.TEXT_MAP, tracing.propagation());
     }