Add support for mapping the Java Period object to a PostgreSQL interv…

…al type #128

In PostgreSQL, an interval may comprise years, months, days, hours,
minutes and seconds. In Java, an interval is distinguished between
a temporal interval (Duration) and a quantity in terms of days, months
and years (Period).

For example `age(timestamp, timestamp)` returns an interval between two
timestamps in days, months and years. The result of this function should
as such be mapped to a Java Period instead of an Duration.

On the contrary, `timestamp - timestamp` returns an interval between two
timestamps in days, hours, minutes and seconds, for which the existing
Duration-based type is appropiate.

changelog.txt

@@ -3,6 +3,8 @@ Version 2.7.0 - IN PROGRESS
 
 Add support for JSON column values for Oracle #131
 
+Add support for mapping the Java Period object to a PostgreSQL interval type #128
+
 Add YearMonthTimestampType #127
 
 Ability to use PostgreSQLEnumType and EnumArrayType with TypedParameterValue #125

hibernate-types-52/src/main/java/com/vladmihalcea/hibernate/type/interval/PostgreSQLPeriodType.java

@@ -0,0 +1,63 @@
+package com.vladmihalcea.hibernate.type.interval;
+
+import com.vladmihalcea.hibernate.type.ImmutableType;
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
+import org.postgresql.util.PGInterval;
+
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Types;
+import java.time.Duration;
+import java.time.Period;
+
+/**
+ * Maps a Java {@link Duration} object to a PostgreSQL Interval column type.
+ *
+ * @author Jan-Willem Gmelig Meyling
+ * @author Vlad Mihalcea
+ * @since 2.6.2
+ */
+public class PostgreSQLPeriodType extends ImmutableType<Period> {
+
+    public static final PostgreSQLPeriodType INSTANCE = new PostgreSQLPeriodType();
+
+    public PostgreSQLPeriodType() {
+        super(Period.class);
+    }
+
+    @Override
+    protected Period get(ResultSet rs, String[] names, SharedSessionContractImplementor session, Object owner) throws SQLException {
+        final PGInterval interval = (PGInterval) rs.getObject(names[0]);
+
+        if (interval == null) {
+            return null;
+        }
+
+        final int years = interval.getYears();
+        final int months = interval.getMonths();
+        final int days = interval.getDays();
+
+        return Period.ofYears(years)
+                .plusMonths(months)
+                .plusDays(days);
+    }
+
+    @Override
+    protected void set(PreparedStatement st, Period value, int index, SharedSessionContractImplementor session) throws SQLException {
+        if (value == null) {
+            st.setNull(index, Types.OTHER);
+        } else {
+            final int days = value.getDays();
+            final int months = value.getMonths();
+            final int years = value.getYears();
+            st.setObject(index, new PGInterval(years, months, days, 0, 0, 0));
+        }
+    }
+
+    @Override
+    public int[] sqlTypes() {
+        return new int[]{Types.OTHER};
+    }
+
+}

hibernate-types-52/src/test/java/com/vladmihalcea/hibernate/type/interval/PostgreSQLPeriodTypeTest.java

@@ -0,0 +1,59 @@
+package com.vladmihalcea.hibernate.type.interval;
+
+import com.vladmihalcea.hibernate.type.model.BaseEntity;
+import com.vladmihalcea.hibernate.type.util.AbstractPostgreSQLIntegrationTest;
+import org.hibernate.annotations.TypeDef;
+import org.junit.Test;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import java.time.Period;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Tests for {@see PostgreSQLIntervalType} Hibernate type.
+ *
+ * @author Jan-Willem Gmelig Meyling
+ */
+public class PostgreSQLPeriodTypeTest extends AbstractPostgreSQLIntegrationTest {
+
+    @Override
+    protected Class<?>[] entities() {
+        return new Class[]{WorkShift.class};
+    }
+
+    @Test
+    public void test() {
+        Period duration = Period.of(1, 2, 3);
+
+        doInJPA(entityManager -> {
+            WorkShift intervalEntity = new WorkShift();
+            intervalEntity.setId(1L);
+            intervalEntity.setDuration(duration);
+
+            entityManager.persist(intervalEntity);
+        });
+
+        doInJPA(entityManager -> {
+            WorkShift result = entityManager.find(WorkShift.class, 1L);
+            assertEquals(duration, result.getDuration());
+        });
+    }
+
+    @Entity(name = "WorkShift")
+    @TypeDef(typeClass = PostgreSQLPeriodType.class, defaultForType = Period.class)
+    public static class WorkShift extends BaseEntity {
+
+        @Column(columnDefinition = "interval")
+        private Period duration;
+
+        public Period getDuration() {
+            return duration;
+        }
+
+        public void setDuration(Period duration) {
+            this.duration = duration;
+        }
+    }
+}