feat: add Content.text() quick accessor

PiperOrigin-RevId: 757886339

Author: jaycee-li

src/main/java/com/google/genai/types/Content.java

@@ -23,9 +23,12 @@
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.google.auto.value.AutoValue;
 import com.google.genai.JsonSerializable;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Optional;
+import java.util.logging.Logger;
+import org.jspecify.annotations.Nullable;
 
 /** Contains the multi-part content of a message. */
 @AutoValue
@@ -76,8 +79,72 @@ public static Content fromJson(String jsonString) {
     return JsonSerializable.fromJsonString(jsonString, Content.class);
   }
 
+  private static final Logger logger = Logger.getLogger(Content.class.getName());
+
   /** Constructs a Content from parts, assuming the role is "user". */
   public static Content fromParts(Part... parts) {
     return builder().role("user").parts(Arrays.asList(parts)).build();
   }
+
+  /**
+   * Returns the concatenation of all text parts in this content.
+   *
+   * <p>Returns null if there are no parts in the content. Returns an empty string if parts exists
+   * but none of the parts contain text.
+   */
+  public @Nullable String text() {
+    return aggregateTextFromParts(parts().orElse(null));
+  }
+
+  /**
+   * Aggregates all text parts in a list of parts.
+   *
+   * <p>Returns null if there are no parts in the list. Returns an empty string if parts exists but
+   * none of the parts contain text.
+   */
+  static @Nullable String aggregateTextFromParts(List<Part> parts) {
+    if (parts == null || parts.isEmpty()) {
+      return null;
+    }
+
+    StringBuilder sb = new StringBuilder();
+    ArrayList<String> nonTextParts = new ArrayList<>();
+    for (Part part : parts) {
+      if (part.inlineData().isPresent()) {
+        nonTextParts.add("inlineData");
+      }
+      if (part.codeExecutionResult().isPresent()) {
+        nonTextParts.add("codeExecutionResult");
+      }
+      if (part.executableCode().isPresent()) {
+        nonTextParts.add("executableCode");
+      }
+      if (part.fileData().isPresent()) {
+        nonTextParts.add("fileData");
+      }
+      if (part.functionCall().isPresent()) {
+        nonTextParts.add("functionCall");
+      }
+      if (part.functionResponse().isPresent()) {
+        nonTextParts.add("functionResponse");
+      }
+      if (part.videoMetadata().isPresent()) {
+        nonTextParts.add("videoMetadata");
+      }
+      if (part.thought().orElse(false)) {
+        continue;
+      }
+      sb.append(part.text().orElse(""));
+    }
+
+    if (!nonTextParts.isEmpty()) {
+      logger.warning(
+          String.format(
+              "There are non-text parts %s in the content, returning concatenation of all text"
+                  + " parts. Please refer to the non text parts for a full response from model.",
+              String.join(", ", nonTextParts)));
+    }
+
+    return sb.toString();
+  }
 }

src/main/java/com/google/genai/types/GenerateContentResponse.java

@@ -144,50 +144,7 @@ public static GenerateContentResponse fromJson(String jsonString) {
    * content.
    */
   public @Nullable String text() {
-    ImmutableList<Part> parts = parts();
-    if (parts == null || parts.isEmpty()) {
-      return null;
-    }
-
-    String text = "";
-    ArrayList<String> nonTextParts = new ArrayList<>();
-    for (Part part : parts) {
-      if (part.inlineData().isPresent()) {
-        nonTextParts.add("inlineData");
-      }
-      if (part.codeExecutionResult().isPresent()) {
-        nonTextParts.add("codeExecutionResult");
-      }
-      if (part.executableCode().isPresent()) {
-        nonTextParts.add("executableCode");
-      }
-      if (part.fileData().isPresent()) {
-        nonTextParts.add("fileData");
-      }
-      if (part.functionCall().isPresent()) {
-        nonTextParts.add("functionCall");
-      }
-      if (part.functionResponse().isPresent()) {
-        nonTextParts.add("functionResponse");
-      }
-      if (part.videoMetadata().isPresent()) {
-        nonTextParts.add("videoMetadata");
-      }
-      if (part.thought().orElse(false)) {
-        continue;
-      }
-      text += part.text().orElse("");
-    }
-
-    if (!nonTextParts.isEmpty()) {
-      logger.warning(
-          String.format(
-              "There are non-text parts %s in the response, returning concatenation of all text"
-                  + " parts. Please refer to the non text parts for a full response from model.",
-              String.join(", ", nonTextParts)));
-    }
-
-    return text;
+    return Content.aggregateTextFromParts(parts());
   }
 
   /**

src/test/java/com/google/genai/types/ContentTest.java

@@ -24,24 +24,71 @@
 
 public class ContentTest {
 
+  private static final String TEXT_1 = "test-text-1";
+  private static final String TEXT_2 = "test-text-2";
+  private static final Part TEXT_PART_1 = Part.fromText(TEXT_1);
+  private static final Part TEXT_PART_2 = Part.fromText(TEXT_2);
+  private static final Part FILE_PART = Part.fromUri("test-uri", "test-mime-type");
+  private static final Part INLINE_DATA_PART =
+      Part.fromBytes(new byte[] {1, 2, 3}, "test-mime-type");
+  private static final Part FUNCTION_CALL_PART =
+      Part.fromFunctionCall("test-function-name", ImmutableMap.of("test-key", "test-value"));
+  private static final Part FUNCTION_RESPONSE_PART =
+      Part.fromFunctionResponse("test-function-name", ImmutableMap.of("test-key", "test-value"));
+
   @Test
   public void testContentFromParts() {
-    Part textPart = Part.fromText("test-text");
-    Part filePart = Part.fromUri("test-uri", "test-mime-type");
-    Part inlineDataPart = Part.fromBytes(new byte[] {1, 2, 3}, "test-mime-type");
-    Part functionCallPart =
-        Part.fromFunctionCall("test-function-name", ImmutableMap.of("test-key", "test-value"));
-    Part functionResponsePart =
-        Part.fromFunctionResponse("test-function-name", ImmutableMap.of("test-key", "test-value"));
-
     Content content =
         Content.fromParts(
-            textPart, filePart, inlineDataPart, functionCallPart, functionResponsePart);
+            TEXT_PART_1, FILE_PART, INLINE_DATA_PART, FUNCTION_CALL_PART, FUNCTION_RESPONSE_PART);
 
     assertEquals(
         ImmutableList.of(
-            textPart, filePart, inlineDataPart, functionCallPart, functionResponsePart),
+            TEXT_PART_1, FILE_PART, INLINE_DATA_PART, FUNCTION_CALL_PART, FUNCTION_RESPONSE_PART),
         content.parts().get());
     assertEquals("user", content.role().get());
   }
+
+  @Test
+  public void testText_ConcatenatesTextParts() {
+    Content content = Content.fromParts(TEXT_PART_1, TEXT_PART_2);
+    String text = content.text();
+
+    assertEquals(TEXT_1 + TEXT_2, text);
+  }
+
+  @Test
+  public void testText_NullParts() {
+    Content content = Content.builder().build();
+    String text = content.text();
+
+    assertEquals(null, text);
+  }
+
+  @Test
+  public void testText_EmptyParts() {
+    Content content = Content.builder().parts(ImmutableList.of()).build();
+    String text = content.text();
+
+    assertEquals(null, text);
+  }
+
+  @Test
+  public void testText_NonTextParts() {
+    Content content =
+        Content.fromParts(
+            TEXT_PART_1, FILE_PART, INLINE_DATA_PART, FUNCTION_CALL_PART, FUNCTION_RESPONSE_PART);
+    String text = content.text();
+
+    assertEquals(TEXT_1, text);
+  }
+
+  @Test
+  public void testText_NoTextParts() {
+    Content content =
+        Content.fromParts(FILE_PART, INLINE_DATA_PART, FUNCTION_CALL_PART, FUNCTION_RESPONSE_PART);
+    String text = content.text();
+
+    assertEquals("", text);
+  }
 }