Fix OpenAI image dimension handling

The OpenAiImageOptions class previously had inconsistent behavior when
setting width and height properties. This change ensures that the size
property is only computed when both dimensions are available, preventing
invalid states in the API requests.

Key changes:
- Update setWidth/setHeight to only set size when both are non-null
- Add test cases to verify null size when dimensions are incomplete
- Improve code organization with proper import conventions

This change aligns with OpenAI's API requirements for image generation
where both dimensions must be specified for valid requests.

Author: dennysfredericci

models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiImageOptions.java

@@ -16,13 +16,12 @@
 
 package org.springframework.ai.openai;
 
-import java.util.Objects;
-
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
-
 import org.springframework.ai.image.ImageOptions;
 
+import java.util.Objects;
+
 /**
  * OpenAI Image API options. OpenAiImageOptions.java
  *
@@ -48,12 +47,18 @@ public class OpenAiImageOptions implements ImageOptions {
 
 	/**
 	 * The width of the generated images. Must be one of 256, 512, or 1024 for dall-e-2.
+	 * This property is interconnected with the 'size' property - setting both width and height
+	 * will automatically compute and set the size in "widthxheight" format. Conversely,
+	 * setting a valid size string will parse and set the individual width and height values.
 	 */
 	@JsonProperty("size_width")
 	private Integer width;
 
 	/**
 	 * The height of the generated images. Must be one of 256, 512, or 1024 for dall-e-2.
+	 * This property is interconnected with the 'size' property - setting both width and height
+	 * will automatically compute and set the size in "widthxheight" format. Conversely,
+	 * setting a valid size string will parse and set the individual width and height values.
 	 */
 	@JsonProperty("size_height")
 	private Integer height;
@@ -76,6 +81,10 @@ public class OpenAiImageOptions implements ImageOptions {
 	/**
 	 * The size of the generated images. Must be one of 256x256, 512x512, or 1024x1024 for
 	 * dall-e-2. Must be one of 1024x1024, 1792x1024, or 1024x1792 for dall-e-3 models.
+	 * This property is automatically computed when both width and height are set, following
+	 * the format "widthxheight". When setting this property directly, it must follow the
+	 * format "WxH" where W and H are valid integers. Invalid formats will result in null
+	 * width and height values.
 	 */
 	@JsonProperty("size")
 	private String size;
@@ -142,9 +151,13 @@ public Integer getWidth() {
 		}
 		else if (this.size != null) {
 			try {
-				return Integer.parseInt(this.size.split("x")[0]);
+				String[] dimensions = this.size.split("x");
+				if (dimensions.length != 2) {
+					return null;
+				}
+				return Integer.parseInt(dimensions[0]);
 			}
-			catch (NumberFormatException ex) {
+			catch (Exception ex) {
 				return null;
 			}
 		}
@@ -153,7 +166,9 @@ else if (this.size != null) {
 
 	public void setWidth(Integer width) {
 		this.width = width;
-		this.size = this.width + "x" + this.height;
+		if (this.width != null && this.height != null) {
+			this.size = this.width + "x" + this.height;
+		}
 	}
 
 	@Override
@@ -163,9 +178,13 @@ public Integer getHeight() {
 		}
 		else if (this.size != null) {
 			try {
-				return Integer.parseInt(this.size.split("x")[1]);
+				String[] dimensions = this.size.split("x");
+				if (dimensions.length != 2) {
+					return null;
+				}
+				return Integer.parseInt(dimensions[1]);
 			}
-			catch (NumberFormatException ex) {
+			catch (Exception ex) {
 				return null;
 			}
 		}
@@ -174,7 +193,9 @@ else if (this.size != null) {
 
 	public void setHeight(Integer height) {
 		this.height = height;
-		this.size = this.width + "x" + this.height;
+		if (this.width != null && this.height != null) {
+			this.size = this.width + "x" + this.height;
+		}
 	}
 
 	@Override

models/spring-ai-openai/src/test/java/org/springframework/ai/openai/OpenAiImageOptionsTests.java

@@ -58,20 +58,56 @@ void whenWidthAndHeightAreSet() {
 	void whenWidthIsSet() {
 		OpenAiImageOptions options = new OpenAiImageOptions();
 		options.setWidth(1920);
-		assertThat(options.getHeight()).isEqualTo(null);
+		assertThat(options.getHeight()).isNull();
 		assertThat(options.getWidth()).isEqualTo(1920);
-		// This is because "setWidth()" computes "size" without checking for null values.
-		assertThat(options.getSize()).isEqualTo("1920xnull");
+		// 1920xnull is not a valid size, so "size" should be null.
+		assertThat(options.getSize()).isNull();
 	}
 
 	@Test
 	void whenHeightIsSet() {
 		OpenAiImageOptions options = new OpenAiImageOptions();
 		options.setHeight(1080);
 		assertThat(options.getHeight()).isEqualTo(1080);
-		assertThat(options.getWidth()).isEqualTo(null);
-		// This is because "setHeight()" computes "size" without checking for null values.
-		assertThat(options.getSize()).isEqualTo("nullx1080");
+		assertThat(options.getWidth()).isNull();
+		// nullx1080 is not a valid size, so "size" should be null.
+		assertThat(options.getSize()).isNull();
+	}
+
+	@Test
+	void whenInvalidSizeFormatIsSet() {
+		OpenAiImageOptions options = new OpenAiImageOptions();
+		options.setSize("invalid");
+		assertThat(options.getHeight()).isNull();
+		assertThat(options.getWidth()).isNull();
+		assertThat(options.getSize()).isEqualTo("invalid");
+	}
+
+	@Test
+	void whenSizeWithInvalidNumbersIsSet() {
+		OpenAiImageOptions options = new OpenAiImageOptions();
+		options.setSize("axb");
+		assertThat(options.getHeight()).isNull();
+		assertThat(options.getWidth()).isNull();
+		assertThat(options.getSize()).isEqualTo("axb");
+	}
+
+	@Test
+	void whenSizeWithMissingDimensionIsSet() {
+		OpenAiImageOptions options = new OpenAiImageOptions();
+		options.setSize("1024x");
+		assertThat(options.getHeight()).isNull();
+		assertThat(options.getWidth()).isNull();
+		assertThat(options.getSize()).isEqualTo("1024x");
+	}
+
+	@Test
+	void whenSizeWithExtraSeparatorsIsSet() {
+		OpenAiImageOptions options = new OpenAiImageOptions();
+		options.setSize("1024x1024x1024");
+		assertThat(options.getHeight()).isNull();
+		assertThat(options.getWidth()).isNull();
+		assertThat(options.getSize()).isEqualTo("1024x1024x1024");
 	}
 
 }