Hooking into or extends the GormInstanceApi methods of the GORM API for Grails

Main class defination

package com.autobill.enhancer

import org.codehaus.groovy.grails.commons.DefaultGrailsDomainClass
import org.codehaus.groovy.grails.orm.hibernate.HibernateDatastore
import org.codehaus.groovy.grails.orm.hibernate.HibernateGormInstanceApi
/**
 * Created by pritom on 17/10/2016.
 */
class MyCustomInstanceApi<D> extends HibernateGormInstanceApi<D> {
    private HibernateGormInstanceApi gormInstanceApi

    MyCustomInstanceApi(HibernateGormInstanceApi gormInstanceApi) {
        super(gormInstanceApi.persistentClass, gormInstanceApi.datastore as HibernateDatastore, gormInstanceApi.classLoader)
        this.gormInstanceApi = gormInstanceApi
    }

    @Override
    D save(D instance) {
        println("Saving-${instance}")
        super.save(instance)
    }

    static void init(servletContext) {
        servletContext.grailsApplication.domainClasses.each { DefaultGrailsDomainClass domainClass ->
            def gormInstanceApi = domainClass.clazz.currentGormInstanceApi()
            domainClass.clazz.setInstanceGormInstanceApi(new MyCustomInstanceApi(gormInstanceApi))
        }
    }
}

And invoke MyCustomInstanceApi.init(servletContext) from Bootstrap.groovy

Get caller class name from inherited static method using java

Base class to test caller call name extractor

package com.pritom.kumar;

/**
 * Created by pritom on 10/10/2016.
 */
abstract class StaticMethodCallerClassName {
    static String returnCallerClassNameUsingThreadStackTrace() {
        StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
        return stackTraceElements[2].getClassName();
    }

    static String returnCallerClassNameUsingThrowable() {
        return new Throwable().getStackTrace()[2].getClassName();
    }

    static String returnCallerClassNameUsingSecurityManager() {
        Class[] classes = CallingClassManager.INSTANCE.getCallingClasses();
        return classes[classes.length - 2].getCanonicalName();
    }

    private static class CallingClassManager extends SecurityManager {
        static final CallingClassManager INSTANCE = new CallingClassManager();

        Class[] getCallingClasses() {
            return getClassContext();
        }
    }

    static void printElapsedTime(String title, Long startTime, String className) {
        startTime = System.nanoTime() - startTime;
        System.out.println(title + " took=" + ((double) startTime) / 1000000D + " ms and class_name=" + className);
    }
}

Example class 1

package com.pritom.kumar;

/**
 * Created by pritom on 10/10/2016.
 */
public class StaticMethodCallerClassNameTest1 extends StaticMethodCallerClassName {
    public static void main(String[] args) {
        x1();
    }

    static void x1() {
        long startTime = System.nanoTime();
        String className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingThreadStackTrace();
        }
        printElapsedTime("ThreadStackTrace", startTime, className);

        startTime = System.nanoTime();
        className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingThrowable();
        }
        printElapsedTime("Throwable", startTime, className);

        startTime = System.nanoTime();
        className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingSecurityManager();
        }
        printElapsedTime("SecurityManager", startTime, className);
    }
}

Example class 2

package com.pritom.kumar;

/**
 * Created by pritom on 10/10/2016.
 */
public class StaticMethodCallerClassNameTest2 extends StaticMethodCallerClassNameTest1 {
    public static void main(String[] args) {
        x2();
    }

    static void x2() {
        long startTime = System.nanoTime();
        String className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingThreadStackTrace();
        }
        printElapsedTime("ThreadStackTrace", startTime, className);

        startTime = System.nanoTime();
        className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingThrowable();
        }
        printElapsedTime("Throwable", startTime, className);

        startTime = System.nanoTime();
        className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingSecurityManager();
        }
        printElapsedTime("SecurityManager", startTime, className);
    }
}

Example class 3

package com.pritom.kumar;

/**
 * Created by pritom on 10/10/2016.
 */
public class StaticMethodCallerClassNameTest3 extends StaticMethodCallerClassNameTest2 {
    public static void main(String[] args) {
        x3();
    }

    static void x3() {
        long startTime = System.nanoTime();
        String className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingThreadStackTrace();
        }
        printElapsedTime("ThreadStackTrace", startTime, className);

        startTime = System.nanoTime();
        className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingThrowable();
        }
        printElapsedTime("Throwable", startTime, className);

        startTime = System.nanoTime();
        className = null;
        for (int i = 0; i < 10000; i++) {
            className = returnCallerClassNameUsingSecurityManager();
        }
        printElapsedTime("SecurityManager", startTime, className);
    }
}

Cannot change column used in a foreign key constraint

Disabling foreign key check using following SQL:
SET FOREIGN_KEY_CHECKS=0;

Enabling foreign key check:
SET FOREIGN_KEY_CHECKS=1;

If you want it globally then:
SET GLOBAL FOREIGN_KEY_CHECKS=0;
SET GLOBAL FOREIGN_KEY_CHECKS=1;

Alter all table of a mysql database using java

package com.pritom.kumar;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by pritom on 18/10/2016.
 */
public class StoredProcedureUtils {
    static Connection connection = null;

    public static void main(String[] args) throws Exception {
        alterTableSchema("some_db_name");
    }

    static void alterTableSchema(String databaseName) throws Exception {
        /* Query for retrieve table names from database */
        String query = "SELECT table_name FROM information_schema.tables " +
                "WHERE table_schema='" + databaseName + "' ORDER BY table_name;";

        /* Create statement */
        Statement statement = getConnection().createStatement();

        /* Retrieving all table names */
        ResultSet resultSet = statement.executeQuery(query);
        List<String> tableList = new ArrayList<String>();
        while (resultSet.next()) {
            tableList.add(resultSet.getString(1));
        }

        /* Set database not to check foreign key constraints */
        statement.execute("SET FOREIGN_KEY_CHECKS=0;");

        /* Alter table structure */
        for (Integer index = 0; index < tableList.size(); index++) {
            String tableName = tableList.get(index);
            try {
                statement.execute("ALTER TABLE " + databaseName + "." + tableName + " MODIFY id BIGINT(20) AUTO_INCREMENT;");
                pl(formatAsLength("Done Alter Table=" + tableName, 70, "") + (index + 1) + " Of " + tableList.size());
            }
            catch (Exception ex) {
                pl(formatAsLength("Error Alter Table=" + tableName, 70, "") + "Error=" + ex.getMessage());
            }
        }

        /* Set database mode to check foreign key constraints again */
        statement.execute("SET FOREIGN_KEY_CHECKS=1;");

        /* Close statement */
        statement.close();
    }

    static Connection getConnection() throws Exception {
        if (connection != null) {
            return connection;
        }
        connection = DriverManager.getConnection("jdbc:mysql://localhost/some_db_name?user=root&password=");
        return connection;
    }

    static void pl(Object o) {
        System.out.println("" + o);
    }

    static String formatAsLength(String number, Integer minLength, String replaceEmptyWith) {
        number = String.format("%-" + minLength + "s", number);
        return replaceEmptyWith.length() > 0 ? number.replace(" ", replaceEmptyWith) : number;
    }
}

How to pass the entire model to a template in Grails

<g:render template="/layouts/view_name" model="${pageScope.variables}"/>

java - JDBC connection error : unrecognized timezone

java.sql.SQLException: The server time zone value is unrecognized or represents more than one time zone

Have to add "serverTimezone" parameter to connect url.

jdbc:mysql://localhost/db?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC

Apparently, to get version 5.1.33 of MySQL JDBC driver to work with UTC time zone, one has to specify the serverTimezone explicitly in the connection string

Grails send email using grails.plugin.mail.MailService and track unique message ID

At first have to extend "grails.plugin.mail.MailService" as follows:

class MyMailService extends MailService MyMailService would be like: package com.pkm.services.mail import grails.plugin.mail.MailMessageBuilder import grails.plugin.mail.MailService import org.springframework.mail.MailMessage import org.springframework.mail.javamail.MimeMessageHelper class MyMailService extends MailService { MailMessage sendMail(Closure callable) { if (isDisabled()) { throw new Exception("Sending emails disabled by configuration option") return null } MailMessageBuilder messageBuilder = mailMessageBuilderFactory.createBuilder(mailConfig) messageBuilder.multipart(true) /* Sending some custom headers with this email */ Map<String, String> v = new HashMap<String,String>() v.put("header_1", "Header_1") v.put("header_2", "Header_2") messageBuilder.headers(v) callable.delegate = messageBuilder callable.resolveStrategy = Closure.DELEGATE_FIRST callable.call(messageBuilder) MailMessage mailMessage = messageBuilder.sendMessage(mailExecutorService) /* Reading unique message ID */ MimeMessageHelper mimeMessageHelper = messageBuilder.getProperty("helper") String messageID = mimeMessageHelper.mimeMessage.getHeader("Message-ID").toString().trim() /* Now you can do your stuff with messageID */ return mailMessage } }

Use below code snippet to send mail

myMailService.sendMail() { mailSender.host = "host.mail.com" mailSender.javaMailProperties.put("mail.smtp.auth", "true") mailSender.username = "pritomkucse@gmail.com" mailSender.password = "xxxxxxxxx" mailSender.port = 569 multipart true from "Pritom<pritomkucse@gmail.com>" to replyTo cc bcc subject text html attachBytes "some.name" "file_type" fileBytes }

You need to add following dependency to BuildConfig.groovy as follows:

grails.project.dependency.resolution = { // inherit Grails' default dependencies inherits("global") { // specify dependency exclusions here; for example, uncomment this to disable ehcache: // excludes 'ehcache' } log "error" // log level of Ivy resolver, either 'error', 'warn', 'info', 'debug' or 'verbose' checksums true // Whether to verify checksums on resolve legacyResolve false // whether to do a secondary resolve on plugin installation, not advised and here for backwards compatibility repositories { inherits true // Whether to inherit repository definitions from plugins grailsPlugins() grailsHome() mavenLocal() grailsCentral() mavenCentral() // uncomment these (or add new ones) to enable remote dependency resolution from public Maven repositories //mavenRepo "http://repository.codehaus.org" //mavenRepo "http://download.java.net/maven/2/" //mavenRepo "http://repository.jboss.com/maven2/" } dependencies { // specify dependencies here under either 'build', 'compile', 'runtime', 'test' or 'provided' scopes e.g. // runtime 'mysql:mysql-connector-java:5.1.29' // runtime 'org.postgresql:postgresql:9.3-1101-jdbc41' test "org.grails:grails-datastore-test-support:1.0.2-grails-2.4" compile "org.springframework:spring-orm:$springVersion" runtime 'mysql:mysql-connector-java:5.1.29' } plugins { // plugins for the build system only build ":tomcat:7.0.55" // plugins for the compile step compile ":scaffolding:2.1.2" compile ':cache:1.1.8' compile ":asset-pipeline:1.9.9" compile ":mail:1.0.5" // plugins needed at runtime but not for compilation runtime ":hibernate4:4.3.6.1" // or ":hibernate:3.6.10.18" runtime ":database-migration:1.4.0" runtime ":jquery:1.11.1" // Uncomment these to enable additional asset-pipeline capabilities //compile ":sass-asset-pipeline:1.9.0" //compile ":less-asset-pipeline:1.10.0" //compile ":coffee-asset-pipeline:1.8.0" //compile ":handlebars-asset-pipeline:1.3.0.3" } }