public Builder addProductCategories(java.lang.String value) {
      if (value == null) {
        throw new NullPointerException();
      }
      ensureProductCategoriesIsMutable();
      productCategories_.add(value);
      bitField0_ |= 0x00000004;
      onChanged();
      return this;
    }
<pre>
The list of product categories to search in. Currently, we only consider
the first category, and either "homegoods-v2", "apparel-v2", "toys-v2",
"packagedgoods-v1", or "general-v1" should be specified. The legacy
categories "homegoods", "apparel", and "toys" are still supported but will
be deprecated. For new products, please use "homegoods-v2", "apparel-v2",
or "toys-v2" for better product search accuracy. It is recommended to
migrate existing products to these categories as well.
</pre>

<code>repeated string product_categories = 7;</code>

@param value The productCategories to add.
@return This builder for chaining.
java-vision/proto-google-cloud-vision-v1/src/main/java/com/google/cloud/vision/v1/ProductSearchParams.java