Some times in our applications, while saving a domain object we may desire to have a save or update behavior on the basis of certain fieldSupp<\/p>\n
Suppose we have a domain class Personwith following definition:<\/p>\n
[java]class Person{
\nString name
\nString source
\nString description<\/p>\n
def static saveOrUpdateBy = [‘name’, ‘source’]<\/p>\n
} [\/java]<\/p>\n
Details of a person are coming from multiple sources at multiple intervals of time. We want to maintain the latest records from each source at any given time.<\/p>\n
We want to saveOrUpdate a person if the name and source are same. So, If we happen to execute following three lines of code…<\/p>\n
[java]new Person(name: ‘Alex’, source: ‘source-1’, ‘Hello’).saveOrUpdate();
\n new Person(name: ‘Alex’, source: ‘source-1’, ‘Hi’).saveOrUpdate();
\n new Person(name: ‘Alex’, source: ‘source-1’, ‘Wow’).saveOrUpdate();[\/java]<\/p>\n
By the end of last line we would like to have only one row in the table corresponding to Person domain. Because we want to saveOrUpdate() on the basis of name , source combination.<\/p>\n
We can have\u00a0 a metaclass method injected in all our domain classes to have this method. The properties to be considered while doing saveOrUpdate can be specified through a static field in class.. Some thing like<\/p>\n
[java]def static saveOrUpdateBy = [‘name’, ‘source’][\/java]<\/p>\n
The following is the piece of code for achieving the same:<\/p>\n
Fetching the static property of the domain class.<\/p>\n
[java]\/\/GrailsDomainClass
\n application.domainClasses.each {
\n domainClass->
\n List saveOrUpdateBy = GrailsClassUtils.getStaticPropertyValue(domainClass.clazz, ‘saveOrUpdateBy’)
\n if(saveOrUpdateBy)
\n {
\n SaveOrUpdatePlugin.addSOUToDomainClass(domainClass, saveOrUpdateBy)
\n }
\n }<\/p>\n
[\/java]<\/p>\n
A method to add a meta-method saveOrUpdate to given domain classes.<\/p>\n
[java]<\/p>\n
class SaveOrUpdatePlugin {<\/p>\n
static void addSOUToDomainClass(GrailsDomainClass domainClassObject, List saveOrUpdateBy) {
\n println "Adding saveOrUpdate method to $domainClassObject.clazz"
\n Class domainClass = domainClassObject.clazz
\n domainClass.metaClass.saveOrUpdate = {
\n def savedInst
\n try {
\n log.debug "[SAVE OR UPDATE] Trying to do saveOrUpdate for ${SaveOrUpdatePlugin.getToStringForGivenFields(delegate, saveOrUpdateBy)}"<\/p>\n
def inst = domainClass.findWhere(delegate.properties.subMap(saveOrUpdateBy))<\/p>\n
if (!inst) {
\n synchronized (domainClass) {
\n inst = domainClass.findWhere(delegate.properties.subMap(saveOrUpdateBy))<\/p>\n
if (!inst) {
\n log.info("[SAVE OR UPDATE] Saving a new object ${SaveOrUpdatePlugin.getToStringForGivenFields(delegate, saveOrUpdateBy)}")
\n if (!delegate.validate()) {
\n delegate.errors.each {
\n log.error "Error while saving scrapedMovie\u00a0 $it"
\n }
\n }<\/p>\n
if (!delegate.save(flush: true)) {
\n delegate.errors.each {
\n log.error it
\n }
\n }
\n log.debug("[SAVE OR UPDATE] Saved a new object with id ${delegate.id} – ${SaveOrUpdatePlugin.getToStringForGivenFields(delegate, saveOrUpdateBy)}")
\n }
\n }
\n }
\n else {
\n log.info "[SAVE OR UPDATE] matching object found: ${SaveOrUpdatePlugin.getToStringForGivenFields(inst, saveOrUpdateBy)}"
\n long id = inst.id
\n \/\/inst.properties = delegate.properties
\n SaveOrUpdatePlugin.copyProperties(domainClassObject, delegate, inst)
\n log.info "[SAVE OR UPDATE] Updating an existing object ${SaveOrUpdatePlugin.getToStringForGivenFields(inst, saveOrUpdateBy)}"
\n if (!inst.save(flush: true)) {
\n inst.errors.each {
\n log.error it
\n }
\n }
\n log.debug("[SAVE OR UPDATE] Updated existing object with id ${inst.id} – ${SaveOrUpdatePlugin.getToStringForGivenFields(inst, saveOrUpdateBy)}")
\n }<\/p>\n
savedInst = domainClass.findWhere(delegate.properties.subMap(saveOrUpdateBy))<\/p>\n
\/\/returning the saved instance…<\/p>\n
} catch (Exception ex) {
\n log.error("Failed to saveOrUpdate the object ${delegate} ", ex)
\n }
\n return savedInst
\n }
\n }<\/p>\n
static String getToStringForGivenFields(def object, List fields) {
\n StringBuilder sb = new StringBuilder()
\n sb.append(object.toString() + " SaveOrUpdateBy: ")
\n fields.each {
\n sb.append(", ${it}=")
\n sb.append(object."$it")
\n }
\n sb.toString().replaceFirst(‘, ‘, ”)
\n }<\/p>\n
static void copyProperties(GrailsDomainClass domainClassObject, def source, def target) {
\n domainClassObject.persistantProperties.each {prop ->
\n if (!(prop.name in [‘dateCreated’, ‘lastUpdated’, ‘id’])) {
\n target."${prop.name}" = source."${prop.name}"
\n \/\/println "adding property ${prop.name}"
\n }
\n }
\n }
\n}
\n[\/java]<\/p>\n
Hope this would help someone in need.<\/pre>\nAny comments \/ suggestion for improvement of the same are most welcome.<\/p>\n
Thanks & Regards
\nMohd Farid
\nfarid@intelligrape.com<\/p>\n","protected":false},"excerpt":{"rendered":"Some times in our applications, while saving a domain object we may desire to have a save or update behavior on the basis of certain fieldSupp Suppose we have a domain class Personwith following definition: [java]class Person{ String name String source String description def static saveOrUpdateBy = [‘name’, ‘source’] } [\/java] Details of a person […]<\/p>\n","protected":false},"author":26,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"iawp_total_views":1},"categories":[7],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/posts\/3365"}],"collection":[{"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/users\/26"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/comments?post=3365"}],"version-history":[{"count":1,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/posts\/3365\/revisions"}],"predecessor-version":[{"id":54611,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/posts\/3365\/revisions\/54611"}],"wp:attachment":[{"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/media?parent=3365"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/categories?post=3365"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/tags?post=3365"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}