feat(spring): improve type conversion in DiminishedReturnsProperty (#2250)

Co-authored-by: Lukáš Petrovický <lukas@petrovicky.net>

Author: chenlingmin

spring-integration/spring-boot-autoconfigure/src/main/java/ai/timefold/solver/spring/boot/autoconfigure/config/DiminishedReturnsProperty.java

@@ -1,5 +1,6 @@
 package ai.timefold.solver.spring.boot.autoconfigure.config;
 
+import java.time.Duration;
 import java.util.Collections;
 import java.util.Set;
 import java.util.TreeSet;
@@ -12,11 +13,29 @@
 
 public enum DiminishedReturnsProperty {
     ENABLED("enabled", DiminishedReturnsProperties::setEnabled,
-            value -> Boolean.parseBoolean((String) value)),
+            value -> {
+                if (value instanceof Boolean b)
+                    return b;
+                if (value instanceof String s)
+                    return Boolean.parseBoolean(s);
+                throw new IllegalArgumentException("Cannot convert (%s) to Boolean".formatted(value));
+            }),
     SLIDING_WINDOW_DURATION("sliding-window-duration", DiminishedReturnsProperties::setSlidingWindowDuration,
-            value -> DurationStyle.detectAndParse((String) value)),
+            value -> {
+                if (value instanceof Duration d)
+                    return d;
+                if (value instanceof String s)
+                    return DurationStyle.detectAndParse(s);
+                throw new IllegalArgumentException("Cannot convert (%s) to Duration".formatted(value));
+            }),
     MINIMUM_IMPROVEMENT_RATIO("minimum-improvement-ratio", DiminishedReturnsProperties::setMinimumImprovementRatio,
-            value -> Double.valueOf((String) value)),;
+            value -> {
+                if (value instanceof Number n)
+                    return n.doubleValue();
+                if (value instanceof String s)
+                    return Double.valueOf(s);
+                throw new IllegalArgumentException("Cannot convert (%s) to Double".formatted(value));
+            }),;
 
     private final String propertyName;
     private final BiConsumer<DiminishedReturnsProperties, Object> propertyUpdater;