{"id":4903,"date":"2011-12-29T23:17:16","date_gmt":"2011-12-29T17:47:16","guid":{"rendered":"http:\/\/www.tothenew.com\/blog\/?p=4903"},"modified":"2011-12-29T23:19:11","modified_gmt":"2011-12-29T17:49:11","slug":"grails-custom-data-binding-in-3-simple-steps","status":"publish","type":"post","link":"https:\/\/www.tothenew.com\/blog\/grails-custom-data-binding-in-3-simple-steps\/","title":{"rendered":"Grails Custom Data Binding in 3 Simple Steps"},"content":{"rendered":"

The other day, Farid<\/a> came with an interesting problem of binding a Time String to java.sql.Time. We straight away found the answer in using a CustomTimeEditor and registering it using a CustomPropertyEditorRegistrar bean. We were able to come arrive at this solution, thanks to this StackOverflow thread<\/a>.<\/p>\n

This set me thinking into using a CustomProperty Editor for, say a Cost object, which could contain a unit and an amount<\/p>\n

[java]<\/p>\n

class Cost{<\/p>\n

String unit \/\/Could be constrained to belong to some range of values<\/p>\n

BigDecimal amount<\/p>\n

}<\/p>\n

[\/java]<\/p>\n

I was able to solve this issue in 3 simple steps which I would like to share with you. I felt that this would take a lesser amount of time compared to the Extended Data Binding Plugin(my gut feeling)<\/p>\n

1. Add a CustomCostEditor to src\/groovy<\/strong><\/p>\n

[java]<\/p>\n

import java.beans.PropertyEditorSupportimport org.springframework.util.StringUtils
\nclass CustomCostEditor extends PropertyEditorSupport {\u00a0 \u00a0 private final boolean allowEmpty
\n CustomCostEditor(boolean allowEmpty) {
\n this.allowEmpty = allowEmpty
\n }
\n @Override
\n void setAsText(String text) {
\n if (this.allowEmpty && !StringUtils.hasText(text)) {
\n \/\/ Treat empty String as null value.
\n setValue(null);
\n } else {
\n setValue(parse(text))
\n }
\n }
\n @Override
\n String getAsText() {
\n Cost cost = (Cost) getValue()
\n return "${cost.unit} ${cost.amount}"
\n }
\n Cost parse(String text){
\n try{
\n new Cost(unit: text.substring(0, text.indexOf(" ")), amount: text.substring(text.indexOf(" ") + 1).toBigDecimal())
\n } catch(Exception exception){
\n throw new IllegalArgumentException("Cost should be of the format ‘Unit Amount’")
\n }
\n }
\n}
\n[\/java]<\/p>\n

The methods which we need to override are setAsText() and getAsText()
\n 2. Add a CustomPropertyEditorRegistrar class, which has a registerCustomEditorMethods<\/strong><\/p>\n

[java]
\nimport org.springframework.beans.PropertyEditorRegistrar
\nimport org.springframework.beans.PropertyEditorRegistry<\/p>\n

class CustomPropertyEditorRegistrar implements PropertyEditorRegistrar{
\n public void registerCustomEditors(PropertyEditorRegistry registry) {
\n registry.registerCustomEditor(Cost.class, new com.intelligrape.example.CustomCostEditor(true));
\n }
\n}
\n[\/java]<\/p>\n

3. Add a spring bean to add an instance of this custom property editor registrar<\/strong>
\nFinally, we create a spring bean by adding the following line in resources.groovy<\/p>\n

[java]
\nbeans = {
\n customPropertyEditorRegistrar(CustomPropertyEditorRegistrar)
\n}
\n[\/java]<\/p>\n

Now, assuming that we have an embedded field cost of type Cost in a domain class Item, we can simply use<\/p>\n

[html]
\n<input type="text" name="cost" value="${fieldValue(bean: item, field:’cost’)}"\/>
\n[\/html]<\/p>\n

and input “$ 123”<\/strong> to store $<\/strong> in the cost.unit<\/strong> and 123<\/strong> in the cost.amount<\/strong>.<\/p>\n

I believe that the possibilities with such an approach are infinite!<\/p>\n","protected":false},"excerpt":{"rendered":"

The other day, Farid came with an interesting problem of binding a Time String to java.sql.Time. We straight away found the answer in using a CustomTimeEditor and registering it using a CustomPropertyEditorRegistrar bean. We were able to come arrive at this solution, thanks to this StackOverflow thread. This set me thinking into using a CustomProperty […]<\/p>\n","protected":false},"author":10,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"iawp_total_views":18},"categories":[7],"tags":[733,735,734,664],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/posts\/4903"}],"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\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/comments?post=4903"}],"version-history":[{"count":0,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/posts\/4903\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/media?parent=4903"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/categories?post=4903"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tothenew.com\/blog\/wp-json\/wp\/v2\/tags?post=4903"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}