#168: explicitly require and possibly convert property types

Author: bbottema

Diff for: src/main/java/org/simplejavamail/internal/util/SimpleConversions.java

@@ -0,0 +1,45 @@
+package org.simplejavamail.internal.util;
+
+import javax.annotation.Nullable;
+
+import static org.simplejavamail.internal.util.Preconditions.assumeTrue;
+
+public class SimpleConversions {
+	
+	@Nullable
+	public static String convertToString(@Nullable final Object value) {
+		return value != null ? value.toString() : null;
+	}
+	
+	@Nullable
+	public static Integer convertToInteger(@Nullable final Object value) {
+		if (value == null || value instanceof Integer) {
+			return (Integer) value;
+		} else if (value instanceof Number) {
+			return ((Number) value).intValue();
+		} else if (value instanceof Boolean) {
+			return ((Boolean) value) ? 1 : 0;
+		} else {
+			assumeTrue(value instanceof String, "Wrong property must have been requested");
+			return Integer.valueOf((String) value);
+		}
+	}
+	
+	@Nullable
+	public static Boolean convertToBoolean(@Nullable final Object value) {
+		if (value == null || value instanceof Boolean) {
+			return (Boolean) value;
+		} else if (value instanceof Number) {
+			return ((Number) value).intValue() != 0;
+		} else {
+			assumeTrue(value instanceof String, "Wrong property must have been requested");
+			String strValue = (String) value;
+			if (strValue.equalsIgnoreCase("true") || strValue.equalsIgnoreCase("1")) {
+				return true;
+			} else if (strValue.equalsIgnoreCase("false") || strValue.equalsIgnoreCase("0")) {
+				return false;
+			}
+			throw new AssertionError("Wrong property must have been requested");
+		}
+	}
+}