Enhance FormBodyPartBuilder create methods for mode support

Author: arturobernalg

httpclient5/src/main/java/org/apache/hc/client5/http/entity/mime/FormBodyPartBuilder.java

@@ -27,6 +27,7 @@
 
 package org.apache.hc.client5.http.entity.mime;
 
+import java.nio.charset.CharsetEncoder;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
@@ -48,24 +49,53 @@ public class FormBodyPartBuilder {
     private String name;
     private ContentBody body;
     private final Header header;
+
+    /**
+     * The multipart mode determining how filenames are encoded in the {@code Content-Disposition}
+     * header, defaults to {@link HttpMultipartMode#STRICT}.
+     *
+     * @since 5.5
+     */
     private HttpMultipartMode mode;
 
+    /**
+     * Reusable encoder for ISO-8859-1 charset checks, improving performance by avoiding
+     * repeated instance creation.
+     */
+    private final CharsetEncoder iso8859_1Encoder = StandardCharsets.ISO_8859_1.newEncoder();
+
+    /**
+     * Creates a new builder instance with the specified name, content body, and multipart mode.
+     *
+     * @param name the name of the form field
+     * @param body the content body of the part
+     * @param mode the {@link HttpMultipartMode} to use, determining filename encoding behavior;
+     *
+     * @return a new {@code FormBodyPartBuilder} instance
+     * @since 5.5
+     */
+    public static FormBodyPartBuilder create(final String name, final ContentBody body, final HttpMultipartMode mode) {
+        return new FormBodyPartBuilder(name, body, mode);
+    }
+
     public static FormBodyPartBuilder create(final String name, final ContentBody body) {
-        return new FormBodyPartBuilder(name, body);
+        return new FormBodyPartBuilder(name, body, HttpMultipartMode.STRICT);
     }
 
     public static FormBodyPartBuilder create() {
         return new FormBodyPartBuilder();
     }
 
-    FormBodyPartBuilder(final String name, final ContentBody body) {
+    FormBodyPartBuilder(final String name, final ContentBody body, final HttpMultipartMode mode) {
         this();
         this.name = name;
         this.body = body;
+        this.mode = mode != null ? mode : HttpMultipartMode.STRICT;
     }
 
     FormBodyPartBuilder() {
         this.header = new Header();
+        this.mode = HttpMultipartMode.STRICT;
     }
 
     public FormBodyPartBuilder setName(final String name) {
@@ -99,29 +129,6 @@ public FormBodyPartBuilder setField(final String name, final String value) {
         return this;
     }
 
-    /**
-     * Sets the multipart mode for this builder, determining how filenames are encoded in the
-     * {@code Content-Disposition} header. The mode affects whether the {@code filename*} parameter
-     * is included for non-ISO-8859-1 filenames.
-     * <p>
-     * In {@link HttpMultipartMode#LEGACY} mode, only the {@code filename} parameter is included
-     * with the raw value, mimicking pre-RFC 7578 behavior. In {@link HttpMultipartMode#STRICT}
-     * or {@link HttpMultipartMode#EXTENDED} modes, the {@code filename*} parameter is added
-     * with RFC 5987 encoding for filenames containing non-ISO-8859-1 characters.
-     * </p>
-     * <p>
-     * If {@code mode} is {@code null}, it defaults to {@link HttpMultipartMode#STRICT}.
-     * </p>
-     *
-     * @param mode the {@link HttpMultipartMode} to use, or {@code null} for default behavior
-     * @return this builder instance for method chaining
-     * @since 5.5
-     */
-    public FormBodyPartBuilder setMode(final HttpMultipartMode mode) {
-        this.mode = mode != null ? mode : HttpMultipartMode.STRICT;
-        return this;
-    }
-
     public FormBodyPartBuilder removeFields(final String name) {
         Args.notNull(name, "Field name");
         this.header.removeFields(name);
@@ -137,8 +144,8 @@ public FormBodyPartBuilder removeFields(final String name) {
      * @return {@code true} if the string can be encoded in ISO-8859-1, {@code false} otherwise
      * @since 5.5
      */
-    private static boolean canEncodeToISO8859_1(final String input) {
-        return StandardCharsets.ISO_8859_1.newEncoder().canEncode(input);
+    private boolean canEncodeToISO8859_1(final String input) {
+        return iso8859_1Encoder.canEncode(input);
     }
 
     /**
@@ -196,5 +203,4 @@ public FormBodyPart build() {
         }
         return new FormBodyPart(this.name, this.body, headerCopy);
     }
-
-}
+}

httpclient5/src/test/java/org/apache/hc/client5/http/entity/mime/TestMultipartForm.java

@@ -295,11 +295,11 @@ void testMultipartFormBrowserCompatibleNonASCIIHeaders() throws Exception {
         @SuppressWarnings("resource")
         final FormBodyPart p1 = FormBodyPartBuilder.create(
                 "field1",
-                new InputStreamBody(new FileInputStream(tmpfile), s1 + ".tmp")).setMode(HttpMultipartMode.LEGACY).build();
+                new InputStreamBody(new FileInputStream(tmpfile), s1 + ".tmp"), HttpMultipartMode.LEGACY).build();
         @SuppressWarnings("resource")
         final FormBodyPart p2 = FormBodyPartBuilder.create(
                 "field2",
-                new InputStreamBody(new FileInputStream(tmpfile), s2 + ".tmp")).setMode(HttpMultipartMode.LEGACY).build();
+                new InputStreamBody(new FileInputStream(tmpfile), s2 + ".tmp"), HttpMultipartMode.LEGACY).build();
         final LegacyMultipart multipart = new LegacyMultipart(
                 StandardCharsets.UTF_8, "foo",
                 Arrays.asList(p1, p2));