Add convenience value builder

Author: trask

api/all/src/main/java/io/opentelemetry/api/common/Value.java

@@ -84,6 +84,11 @@ static Value<List<KeyValue>> of(Map<String, Value<?>> value) {
     return KeyValueList.createFromMap(value);
   }
 
+  /** Returns a new {@link ValueBuilder} instance for creating an arbitrary {@link Value}. */
+  static ValueBuilder builder() {
+    return new ValueBuilderImpl();
+  }
+
   /** Returns the type of this {@link Value}. Useful for building switch statements. */
   ValueType getType();
 

api/all/src/main/java/io/opentelemetry/api/common/ValueBuilder.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.api.common;
+
+public interface ValueBuilder {
+
+  default ValueBuilder put(String key, String value) {
+    put(key, Value.of(value));
+    return this;
+  }
+
+  default ValueBuilder put(String key, long value) {
+    put(key, Value.of(value));
+    return this;
+  }
+
+  default ValueBuilder put(String key, double value) {
+    put(key, Value.of(value));
+    return this;
+  }
+
+  default ValueBuilder put(String key, boolean value) {
+    put(key, Value.of(value));
+    return this;
+  }
+
+  ValueBuilder put(String key, Value<?> value);
+
+  Value<?> build();
+}

api/all/src/main/java/io/opentelemetry/api/common/ValueBuilderImpl.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.api.common;
+
+import java.util.ArrayList;
+import java.util.List;
+
+class ValueBuilderImpl implements ValueBuilder {
+
+  private final List<KeyValue> keyValues = new ArrayList<>();
+
+  @Override
+  public ValueBuilder put(String key, Value<?> value) {
+    keyValues.add(KeyValue.of(key, value));
+    return this;
+  }
+
+  @Override
+  public Value<?> build() {
+    return Value.of(keyValues.toArray(new KeyValue[0]));
+  }
+}