je/examples/persist/sqlapp/SQLApp.java
2021-06-06 13:46:45 -04:00

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/*-
* Copyright (C) 2002, 2017, Oracle and/or its affiliates. All rights reserved.
*
* This file was distributed by Oracle as part of a version of Oracle Berkeley
* DB Java Edition made available at:
*
* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
*
* Please see the LICENSE file included in the top-level directory of the
* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
* license and additional information.
*/
package persist.sqlapp;
import java.io.File;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.Environment;
import com.sleepycat.je.EnvironmentConfig;
import com.sleepycat.persist.EntityStore;
import com.sleepycat.persist.ForwardCursor;
import com.sleepycat.persist.StoreConfig;
/**
* An example shows how some common SQL queries are implemented using DPL.
*
* @see #usage
*
* @author chao
*/
public class SQLApp {
private static String envDir = "./tmp";
private static boolean cleanEnvOnExit = false;
private static Environment env = null;
private static EntityStore store = null;
private static DataAccessor dao = null;
/**
* Setup a Berkeley DB engine environment, and preload some example records.
*
* @throws com.sleepycat.je.DatabaseException
*/
public void setup()
throws DatabaseException {
/* Open a transactional Berkeley DB engine environment. */
EnvironmentConfig envConfig = new EnvironmentConfig();
envConfig.setAllowCreate(true);
envConfig.setTransactional(true);
env = new Environment(new File(envDir), envConfig);
/* Open a transactional entity store. */
StoreConfig storeConfig = new StoreConfig();
storeConfig.setAllowCreate(true);
storeConfig.setTransactional(true);
store = new EntityStore(env, "SQLAppStore", storeConfig);
/* Initialize the data access object. */
dao = new DataAccessor(store);
/* Preload some example records. */
loadDepartmentDb();
loadEmployeeDb();
}
/* Load the department database. */
private void loadDepartmentDb()
throws DatabaseException {
dao.departmentById.put
(new Department(1, "CEO Office", "North America"));
dao.departmentById.put
(new Department(2, "Sales", "EURO"));
dao.departmentById.put
(new Department(3, "HR", "MEA"));
dao.departmentById.put
(new Department(4, "Engineering", "APAC"));
dao.departmentById.put
(new Department(5, "Support", "LATAM"));
}
/* Load the employee database. */
private void loadEmployeeDb()
throws DatabaseException {
/* Add the corporate's CEO using the Employee primary index. */
dao.employeeById.put(new Employee(1, // employeeId
"Abraham Lincoln", //employeeName
10000.0f, //salary
null, //managerId
1, //departmentId
"Washington D.C., USA")); //address
/* Add 4 managers responsible for 4 departments. */
dao.employeeById.put(new Employee(2,
"Augustus",
9000.0f,
1,
2,
"Rome, Italy"));
dao.employeeById.put(new Employee(3,
"Cleopatra",
7000.0f,
1,
3,
"Cairo, Egypt"));
dao.employeeById.put(new Employee(4,
"Confucius",
7500.0f,
1,
4,
"Beijing, China"));
dao.employeeById.put(new Employee(5,
"Toussaint Louverture",
6800.0f,
1,
5,
"Port-au-Prince, Haiti"));
/* Add 2 employees per department. */
dao.employeeById.put(new Employee(6,
"William Shakespeare",
7300.0f,
2,
2,
"London, England"));
dao.employeeById.put(new Employee(7,
"Victor Hugo",
7000.0f,
2,
2,
"Paris, France"));
dao.employeeById.put(new Employee(8,
"Yitzhak Rabin",
6500.0f,
3,
3,
"Jerusalem, Israel"));
dao.employeeById.put(new Employee(9,
"Nelson Rolihlahla Mandela",
6400.0f,
3,
3,
"Cape Town, South Africa"));
dao.employeeById.put(new Employee(10,
"Meiji Emperor",
6600.0f,
4,
4,
"Tokyo, Japan"));
dao.employeeById.put(new Employee(11,
"Mohandas Karamchand Gandhi",
7600.0f,
4,
4,
"New Delhi, India"));
dao.employeeById.put(new Employee(12,
"Ayrton Senna da Silva",
5600.0f,
5,
5,
"Brasilia, Brasil"));
dao.employeeById.put(new Employee(13,
"Ronahlinho De Assis Moreira",
6100.0f,
5,
5,
"Brasilia, Brasil"));
}
/** Run the SQL examples. */
public void runApp()
throws DatabaseException {
/* Print departmemt database contents order by departmentId. */
System.out.println("SELECT * FROM department ORDER BY departmentId;");
printQueryResults(dao.departmentById.entities());
/* Print departmemt database contents order by departmentName. */
System.out.println("SELECT * FROM department " +
"ORDER BY departmentName;");
printQueryResults(dao.departmentByName.entities());
/* Print employee database contents order by employeeId. */
System.out.println("SELECT * FROM employee ORDER BY employeeId;");
printQueryResults(dao.employeeById.entities());
/* Do a prefix query. */
System.out.println("SELECT * FROM employee WHERE employeeName " +
"LIKE 'M%';");
printQueryResults(dao.doPrefixQuery(dao.employeeByName, "M"));
/* Do a range query. */
System.out.println("SELECT * FROM employee WHERE salary >= 6000 AND " +
"salary <= 8000;");
printQueryResults(dao.doRangeQuery(dao.employeeBySalary,
new Float(6000), //fromKey
true, //fromInclusive
new Float(8000), //toKey
true)); //toInclusive
/* Two conditions join on a single primary database. */
System.out.println("SELECT * FROM employee " +
"WHERE employeeName = 'Victor Hugo' " +
"AND departmentId = 2;");
printQueryResults(dao.doTwoConditionsJoin(dao.employeeById,
dao.employeeByName,
new String("Victor Hugo"),
dao.employeeByDepartmentId,
new Integer(2)));
/*
* Two conditions join on two primary databases combined with a
* secondary key search.
*/
System.out.println("SELECT * FROM employee e, department d " +
"WHERE e.departmentId = d.departmentId " +
"AND d.departmentName = 'Engineering';");
dao.getEmployeeByDeptName("Engineering");
/*
* Two conditions join on two primary databases combined with a
* filtering on the non-secondary-key.
*/
System.out.println("SELECT * FROM employee e, department d " +
"WHERE e.departmentId = d.departmentId " +
"AND d.location = 'North America';");
dao.getEmployeeByDeptLocation("North America");
}
/** Print query results. */
public <V> void printQueryResults(ForwardCursor<V> cursor)
throws DatabaseException {
try {
for (Object entity : cursor) {
System.out.println(entity);
}
System.out.println();
} finally {
cursor.close();
}
}
/**
* Close the store and environment.
*/
public void close() {
if (store != null) {
try {
store.close();
} catch (DatabaseException dbe) {
System.err.println("Error closing store: " +
dbe.toString());
System.exit(-1);
}
}
if (env != null) {
try {
// Finally, close environment.
env.close();
} catch (DatabaseException dbe) {
System.err.println("Error closing env: " +
dbe.toString());
System.exit(-1);
}
}
if (cleanEnvOnExit) {
removeDbFiles();
}
}
private void removeDbFiles() {
File file = new File(envDir);
for (File f : file.listFiles()) {
f.delete();
}
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
/* Parse the arguments list. */
parseArgs(args);
try {
SQLApp s = new SQLApp();
s.setup();
s.runApp();
s.close();
} catch (DatabaseException e) {
e.printStackTrace();
System.exit(-1);
}
}
/* Parse input arguments. */
private static void parseArgs(String args[]) {
for(int i = 0; i < args.length; ++i) {
if (args[i].startsWith("-")) {
switch(args[i].charAt(1)) {
case 'h':
envDir = args[++i];
break;
case 'd':
cleanEnvOnExit = true;
break;
default:
usage();
}
}
}
}
private static void usage() {
System.out.println("Usage: java SQLApp" +
"\n [-h <env directory>] " +
"# environment home directory" +
"\n [-d] # clean environment after program exits");
System.exit(-1);
}
}