Grails Error Handling With Custom Http Status Code

First need to create a trait Groovy file as follows under src/groovy:

trait CustomExceptionHandler {
    /* Handle common exception */
    def handleException(Exception e) {
        handleCustomException(new CustomException(e.getMessage()))
    }

    /* Handle defined custom exception */
    def handleCustomException2(CustomException2 e) {
        handleCustomException(e)
    }

    /* Handle defined custom exception */
    def handleCustomException(CustomException e) {
        if (!CommonUtils.request) {
            // do something
        }
        else {
            CommonUtils.currentResponse.status = 220 (Custom response code)
            if(e.getStatusCode()) {
                CommonUtils.currentResponse.status = e.getStatusCode()
            }
            if (CommonUtils.request.xhr) {
                def error = [
                        type: "error",
                        message: e.getMessage()
                ]
                render error as JSON
            }
            else {
                render(view: "/error/error", model: [exception: e])
            }
        }
    }
}

Create a groovy class under src/groovy:

import org.springframework.web.context.request.RequestContextHolder
class CommonUtils {
    public static def getRequest() {
        def request = RequestContextHolder.getRequestAttributes()
        return request ? request.request : null
    }

    public static HttpServletResponse getCurrentResponse() {
        return WebUtils.retrieveGrailsWebRequest().getCurrentResponse()
    }
}

Exception Types (Reside in src/groovy):

class CustomException extends RuntimeException {

}
class CustomException2 extends CustomException {

}

How controller can use this feature:

class Controller1 implements CustomExceptionHandler {
    def index() {
        throw new Exception("Common exception")
    }

    def index2() {
        throw new CustomException("Defined custom exception")
    }

    def index3() {
        someService.index3()
    }

    def index4() {
        someService.index4()
    }
}

Exception thrown from service bahave same as from controller

class SomeService {
    def index3() {
        throw new Exception("Common exception")
    }

    def index4() {
        throw new CustomException("Defined custom exception")
    }
}

Java Code To Check Repeated Character In String

import java.util.regex.Pattern;
import java.util.regex.Matcher;

class RepeatedCharacterCheck {
    public static void main (String[] args) throws java.lang.Exception {
        String stringToMatch = "abccdeeefenonn";
        Pattern p = Pattern.compile("(\\w)\\1+");
        Matcher m = p.matcher(stringToMatch);
        while (m.find()) {
            System.out.println("Duplicate character " + m.group(0));
        }
    }
}

Output

Duplicate character cc
Duplicate character eee
Duplicate character nn

Using a CASE Statement/If Condition in HQL select query

SELECT name, 

CASE WHEN name = 'Name' then 'Name is Name' else 'Name is not Name' end
From Domain

HQL Use MySQL Functions By Implementing Custom Dialect

Datasource.groovy File

hibernate {
    cache.use_second_level_cache = true
    cache.use_query_cache = true
    cache.region.factory_class = 'net.sf.ehcache.hibernate.EhCacheRegionFactory'
    cache.provider_class = 'net.sf.ehcache.hibernate.EhCacheProvider'
    format_sql = false
    use_sql_comments = false
}
grails.cache.config = {
    cache {
        name 'org.hibernate.cache.UpdateTimestampsCache'
        eternal true
        maxEntriesLocalHeap 500
        persistence {
            strategy localTempSwap
        }
    }
}

/* environment specific settings */
environments {
    development {
        dataSource {
            pooled = true
            url = "jdbc:mysql://localhost/db_name?useUnicode=yes&characterEncoding=UTF-8"
            driverClassName = "com.mysql.jdbc.Driver"
            username = "root"
            password = ""
            dialect = "com.pkm.custom.CustomMySQLDialect"
            dbCreate = "update"
            properties {
                maxActive = 1000
                maxIdle = 100
                minIdle = 50
                initialSize = 1
                minEvictableIdleTimeMillis = 60000
                timeBetweenEvictionRunsMillis = 60000
                numTestsPerEvictionRun = 3
                maxWait = 10000
                testOnBorrow = true
                testWhileIdle = true
                testOnReturn = true
                validationQuery = "SELECT 1"
                minEvictableIdleTimeMillis = 1800000
                timeBetweenEvictionRunsMillis = 1800000
            }
            logSql = false
            loggingSql = false
        }
    }
    test {
        dataSource {
            
        }
    }
    production {
        dataSource {
            
        }
    }
}
log4j = {
    debug 'org.hibernate.SQL'
    trace 'org.hibernate.type.descriptor.sql.BasicBinder'
}

Custom Dialect (.groovy) Used In Datasource

import org.hibernate.dialect.MySQL5InnoDBDialect
import org.hibernate.dialect.function.SQLFunctionTemplate
import org.hibernate.dialect.function.StandardSQLFunction
import org.hibernate.type.IntegerType
import org.hibernate.type.StringType
import org.hibernate.type.TimestampType

class CustomMySQLDialect extends MySQL5InnoDBDialect {
    public CustomMySQLDialect() {
        super()

        /* convert_tz('2015-01-01', '+00:00', '+10:00') = '2015-01-01 10:00' */
        /* convert_tz('2015-01-01 00:00', '+00:00', '+10:00') = '2015-01-01 10:00' */
        /* convert_tz('2015-01-01 20:00', '+00:00', '-10:00') = '2015-01-01 10:00' */
        registerFunction("convert_tz", new StandardSQLFunction("convert_tz"))

        /* group_concat(name) = 'a,b,c,c,d' */
        registerFunction("group_concat", new StandardSQLFunction("group_concat", new StringType()))

        /* group_concat_unique(name) = 'a,b,c,d' */
        registerFunction("group_concat_unique", new SQLFunctionTemplate(new StringType(), "group_concat(DISTINCT ?1)"))

        /* date_add_interval('2015-01-01', DAY, 10) = '2015-01-11' */
        /* date_add_interval('2015-01-20', DAY, -10) = '2015-01-10' */
        registerFunction("date_add_interval", new SQLFunctionTemplate(TimestampType.INSTANCE, "date_add(?1, INTERVAL ?3 ?2)"))

        /* index_of('am', 'i am good') = 3 */
        /* index_of('asm', 'i am good') = 0 */
        registerFunction("index_of", new SQLFunctionTemplate(new IntegerType(), "LOCATE(?1, ?2)"))

        /* format(number, decimal_place, locale) = format(200.343, 2, 'en_AU') = '200.34' */
        registerFunction("format", new StandardSQLFunction("format", new StringType()))
    }

    @Override
    public String transformSelectString(String select) {
        select = super.transformSelectString(select);
        return select;
    }
}

Myob Cloud Integration: Use Filter In Myob Integration

Equal Method (String)
{domain}/{cf guid}/Sale/Invoice/?$filter=PaymentDetails/Method eq 'Cash'

Equal Method (UID)
{domain}/{cf guid}/Sale/Invoice/?$filter=Customer/UID eq guid'd61a6a86-453a-48bf-9402-6eb6b4ea23cf'

Equal Method (Boolean)
{domain}/{cf guid}/Contact/?$filter=IsIndividual eq true

Filtering in List
{domain}/{cf guid}/Contact/Customer/?$filter=Addresses/any(x: x/Email eq null) 

Equal Method (Date)
{domain}/{cf guid}/Purchase/Bill/?$filter=Date ge datetime'2014-07-01' and Date le datetime'2014-09-24'

Grails Get/Use Http Session In Service Or Util Class

import org.codehaus.groovy.grails.web.util.WebUtils
import javax.servlet.http.HttpSession

HttpSession httpSession = WebUtils.retrieveGrailsWebRequest().request.session

Grails :: How To Override g Message Tag

1. Create a tab lib (grails-app/taglib)

2. Extend with ValidationTagLib

3. Example

package com.test.taglib

import org.codehaus.groovy.grails.plugins.web.taglib.ValidationTagLib

class MyCustomTagLib extends ValidationTagLib {
 static validationTagLibStatic = null

    static namespace = "g"

    Closure message = { attrs ->
        ValidationTagLib validationTagLib = validationTagLibStatic ?: (validationTagLibStatic = grailsAttributes.applicationContext.getBean('org.codehaus.groovy.grails.plugins.web.taglib.ValidationTagLib'))
        validationTagLib.message.call(attrs)
    }
}