Add public ref doc

Author: wu-hui

google-cloud-firestore/src/main/java/com/google/cloud/firestore/PipelineUtils.java

@@ -62,7 +62,7 @@ static FilterCondition toPipelineFilterCondition(FilterInternal f) {
           return and(field.exists(), inAny(field, Lists.newArrayList(valuesList)));
         case ARRAY_CONTAINS_ANY:
           List<Value> valuesListAny = value.getArrayValue().getValuesList();
-          return and(field.exists(), arrayContainsAny(field, valuesListAny.toArray()));
+          return and(field.exists(), arrayContainsAny(field, Lists.newArrayList(valuesListAny)));
         case NOT_IN:
           List<Value> notInValues = value.getArrayValue().getValuesList();
           return and(field.exists(), not(inAny(field, Lists.newArrayList(notInValues))));

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/expressions/Field.java

@@ -8,6 +8,22 @@
 import com.google.firestore.v1.Value;
 import javax.annotation.Nullable;
 
+/**
+ * Represents a reference to a field in a Firestore document.
+ *
+ * <p>Field references are used to access document field values in expressions and to specify fields
+ * for sorting, filtering, and projecting data in Firestore pipelines.
+ *
+ * <p>You can create a `Field` instance using the static {@link #of(String)} method:
+ *
+ * <pre>{@code
+ * // Create a Field instance for the 'name' field
+ * Field nameField = Field.of("name");
+ *
+ * // Create a Field instance for a nested field 'address.city'
+ * Field cityField = Field.of("address.city");
+ * }</pre>
+ */
 @BetaApi
 public final class Field implements Expr, Selectable {
   public static final String DOCUMENT_ID = "__name__";
@@ -18,6 +34,25 @@ private Field(FieldPath path) {
     this.path = path;
   }
 
+  /**
+   * Creates a {@code Field} instance representing the field at the given path.
+   *
+   * <p>The path can be a simple field name (e.g., "name") or a dot-separated path to a nested field
+   * (e.g., "address.city").
+   *
+   * <p>Example:
+   *
+   * <pre>{@code
+   * // Create a Field instance for the 'title' field
+   * Field titleField = Field.of("title");
+   *
+   * // Create a Field instance for a nested field 'author.firstName'
+   * Field authorFirstNameField = Field.of("author.firstName");
+   * }</pre>
+   *
+   * @param path The path to the field.
+   * @return A new {@code Field} instance representing the specified field.
+   */
   @BetaApi
   public static Field of(String path) {
     if (path.equals(DOCUMENT_ID)) {
@@ -52,9 +87,4 @@ public int hashCode() {
   public FieldPath getPath() {
     return path;
   }
-
-  @InternalApi
-  public Pipeline getPipeline() {
-    return pipeline;
-  }
 }

google-cloud-firestore/src/main/java/com/google/cloud/firestore/pipeline/expressions/Fields.java

@@ -7,6 +7,23 @@
 import java.util.List;
 import java.util.stream.Collectors;
 
+/**
+ * Represents a selection of multiple {@link Field} instances.
+ *
+ * <p>This class is used to conveniently specify multiple fields for operations like selecting
+ * fields in a pipeline.
+ *
+ * <p>Example:
+ *
+ * <pre>{@code
+ * // Select the 'name', 'email', and 'age' fields
+ * Fields selectedFields = Fields.of("name", "email", "age");
+ *
+ * firestore.pipeline().collection("users")
+ *     .select(selectedFields)
+ *     .execute();
+ * }</pre>
+ */
 @BetaApi
 public final class Fields implements Expr, Selectable {
   private final List<Field> fields;
@@ -15,18 +32,38 @@ private Fields(List<Field> fs) {
     this.fields = fs;
   }
 
+  /**
+   * Creates a {@code Fields} instance containing the specified fields.
+   *
+   * @param f1 The first field to include.
+   * @param f Additional fields to include.
+   * @return A new {@code Fields} instance containing the specified fields.
+   */
   @BetaApi
   public static Fields of(String f1, String... f) {
     List<Field> fields = Arrays.stream(f).map(Field::of).collect(Collectors.toList());
     fields.add(0, Field.of(f1)); // Add f1 at the beginning
     return new Fields(fields);
   }
 
+  /**
+   * Creates a {@code Fields} instance representing a selection of all fields.
+   *
+   * <p>This is equivalent to not specifying any fields in a select operation, resulting in all
+   * fields being included in the output.
+   *
+   * @return A new {@code Fields} instance representing all fields.
+   */
   @BetaApi
   public static Fields ofAll() {
     return new Fields(Collections.singletonList(Field.of("")));
   }
 
+  /**
+   * Returns the list of {@link Field} instances contained in this {@code Fields} object.
+   *
+   * @return The list of fields.
+   */
   @InternalApi
   public List<Field> getFields() {
     return fields;