import java.io.BufferedReader; import java.io.File; import java.io.FileReader; import java.io.Reader; import java.util.SortedSet; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.OneToMany; import javax.persistence.Table; import org.apache.log4j.BasicConfigurator; import org.apache.log4j.Level; import org.apache.log4j.Logger; import org.hibernate.annotations.Sort; import org.hibernate.annotations.SortType; import org.hibernate.cfg.AnnotationConfiguration; import org.hibernate.cfg.Configuration; import org.hibernate.tool.hbm2ddl.SchemaExport; /** * Example on how one might use hibernate annotations to create a parent/child * relationship * * @author Jake Carr <resume@dawley-carr.org> * * @version 2007-01-02 */ public class ParentChild { /** * getter/setter removed for brevity */ @Entity @Table(name = "parent") public static class Parent { @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "parent_id") protected Long id; @OneToMany(mappedBy = "parent") @Sort(type = SortType.COMPARATOR, comparator = Child.Comparator.class) protected SortedSet childSet; } /** * getter/setter removed for brevity */ @Entity @Table(name = "child") public static class Child { public static class Comparator implements java.util.Comparator { public int compare(Child a, Child b) { int retval = 0; if (retval == 0) { retval = a.lastName.compareTo(b.lastName); } if (retval == 0) { retval = a.firstName.compareTo(b.firstName); } return retval; } } @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "child_id") protected Long id; @Column(name = "last_name", nullable = false) protected String lastName; @Column(name = "first_name", nullable = false) protected String firstName; @ManyToOne @JoinColumn(name = "parent_id") protected Parent parent; @Override public boolean equals(Object o) { if (o instanceof Child) { Child a = (Child) o; if (!lastName.equals(a.lastName)) { return false; } if (!firstName.equals(a.firstName)) { return false; } return true; } return false; } @Override public int hashCode() { int retval = 2; retval += 3 * lastName.hashCode(); retval += 3 * firstName.hashCode(); return retval; } @Override public String toString() { return lastName + ", " + firstName; } } private static final Logger log = Logger.getLogger(ParentChild.class); public static void dumpSchema() throws Exception { BasicConfigurator.configure(); Logger.getRootLogger().setLevel(Level.INFO); File file = File.createTempFile("tmp.", ".tmp"); file.deleteOnExit(); Configuration configuration = getConfiguration(); SchemaExport export = new SchemaExport(configuration); export.setDelimiter(";"); export.setFormat(true); export.setOutputFile(file.getAbsolutePath()); export.execute(false, false, false, true); Reader rawReader = new FileReader(file); BufferedReader reader = new BufferedReader(rawReader); String line; while ((line = reader.readLine()) != null) { log.info(line); } reader.close(); } public static Configuration getConfiguration() { AnnotationConfiguration configuration = new AnnotationConfiguration(); configuration.addAnnotatedClass(Parent.class); configuration.addAnnotatedClass(Child.class); configuration.setProperty("hibernate.dialect", "org.hibernate.dialect.HSQLDialect"); return configuration; } public static void main(String[] argv) throws Exception { dumpSchema(); } }