My goal was to create a simple, extensible Enum converter that would work with<\/p>\n
iBatis<\/a>. This seems like a trivial problem, but took me a while to find a proper solution. There were some additional preconditions: “No big deal”, you say. I beg to differ. What I wanted to achieve was a simple construction which would look like this when used for another Enum (CommonEnumTypeHandler is the name of my generic converter):<\/p>\n Unfortunately due to the fact, that Java does not have reified generics, which is described in<\/p>\n multiple<\/a> places<\/a>, I had to stick with passing through a Class type of my enum. So it looks like this:<\/p>\n My final class has to look like this one below:<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":"My goal was to create a simple, extensible Enum converter that would work with iBatis. This seems like…\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[687,68],"class_list":{"0":"post-241","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-development-design","7":"tag-db","8":"tag-java"},"_links":{"self":[{"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/posts\/241","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/comments?post=241"}],"version-history":[{"count":7,"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/posts\/241\/revisions"}],"predecessor-version":[{"id":15349,"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/posts\/241\/revisions\/15349"}],"wp:attachment":[{"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/media?parent=241"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/categories?post=241"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/touk.pl\/blog\/wp-json\/wp\/v2\/tags?post=241"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n* all given Enums are jaxb generated objects – but any standard Java Enum should work
\n* conversion was 1-to-1, no special conditions and processing The example Enum for this problem looks like this one (copy&paste from jaxb generated source):<\/p>\n@XmlType(name =\"ServiceType\") \r\n@XmlEnum\r\npublic enum ServiceType {\r\n\r\n @XmlEnumValue(\"stationary\")\r\n STATIONARY(\"stationary\"),\r\n @XmlEnumValue(\"mobile\")\r\n MOBILE(\"mobile\");\r\n private final String value;\r\n\r\n ServiceType(String v) {\r\n value = v;\r\n }\r\n\r\n public String value() {\r\n return value;\r\n }\r\n\r\n public static ServiceType fromValue(String v) {\r\n for (ServiceType c: ServiceType.values()) {\r\n if (c.value.equals(v)) {\r\n return c;\r\n }\r\n }\r\n throw new IllegalArgumentException(v);\r\n }\r\n\r\n}<\/pre>\npublic class ServiceTypeHandler extends CommonEnumTypeHandler { }<\/pre>\npublic class ServiceTypeHandler extends CommonEnumTypeHandler {\r\n\r\n public ServiceTypeHandler() {\r\n super(ServiceType.class);\r\n }\r\n}<\/pre>\nimport java.sql.SQLException;\r\n\r\nimport com.ibatis.sqlmap.client.extensions.ParameterSetter;\r\nimport com.ibatis.sqlmap.client.extensions.ResultGetter;\r\nimport com.ibatis.sqlmap.client.extensions.TypeHandlerCallback;\r\n\r\npublic abstract class CommonEnumTypeHandler implements TypeHandlerCallback {\r\n\r\n Class enumClass;\r\n\r\n public CommonEnumTypeHandler(Class clazz) {\r\n this.enumClass = clazz;\r\n }\r\n\r\n public void setParameter(ParameterSetter ps, Object o) throws SQLException {\r\n if (o.getClass().isAssignableFrom(enumClass)) {\r\n ps.setString(((T) o).name().toUpperCase());\r\n } else\r\n throw new SQLException(\"Excpected \" + enumClass + \" object than: \" + o);\r\n }\r\n\r\n public Object getResult(ResultGetter rs) throws SQLException {\r\n Object o = valueOf(rs.getString());\r\n if (o == null)\r\n throw new SQLException(\"Unknown parameter type: \" + rs.getString());\r\n return o;\r\n }\r\n\r\n public Object valueOf(String s) {\r\n return Enum.valueOf(enumClass, s.toUpperCase());\r\n }\r\n}<\/pre>\n