Added string to date conversion

Author: bbottema

src/main/java/org/bbottema/javareflection/valueconverter/converters/StringConverters.java

@@ -15,8 +15,12 @@
 import java.io.File;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.text.DateFormat;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Date;
 import java.util.UUID;
 
 import static org.slf4j.LoggerFactory.getLogger;
@@ -60,6 +64,7 @@ public final class StringConverters {
 		converters.add(new ValueFunctionImpl<>(String.class, BigDecimal.class, new StringToBigDecimalFunction()));
 		converters.add(new ValueFunctionImpl<>(String.class, File.class, new StringToFileFunction()));
 		converters.add(new ValueFunctionImpl<>(String.class, UUID.class, new StringToUUIDFunction()));
+		converters.add(new ValueFunctionImpl<>(String.class, Date.class, new StringToDateFunction()));
 		return converters;
 	}
 
@@ -229,4 +234,25 @@ public UUID apply(String value) {
 			}
 		}
 	}
+	
+	static class StringToDateFunction implements Function<String, Date> {
+		
+		// Quoted "Z" to indicate UTC, no timezone offset
+		private static final DateFormat DATETIME_FORMAT_SIMPLE = new SimpleDateFormat("yyyy-MM-dd");
+		private static final DateFormat DATETIME_FORMAT_ISO8601 = new SimpleDateFormat("yyyy-MM-dd HH:mm");
+		private IllegalArgumentException INCOMPATIBLE_EXCEPTION = new IllegalArgumentException("not compatible with yyyy-MM-dd or yyyy-MM-dd HH:mm");
+		
+		@Override
+		public Date apply(String value) {
+			try {
+				return DATETIME_FORMAT_ISO8601.parse(value);
+			} catch (IllegalArgumentException | ParseException e1) {
+				try {
+					return DATETIME_FORMAT_SIMPLE.parse(value);
+				} catch (IllegalArgumentException | ParseException e2) {
+					throw new IncompatibleTypeException(value, String.class, Date.class, INCOMPATIBLE_EXCEPTION);
+				}
+			}
+		}
+	}
 }

src/test/java/org/bbottema/javareflection/valueconverter/converters/StringToDateFunctionTest.java

@@ -0,0 +1,29 @@
+package org.bbottema.javareflection.valueconverter.converters;
+
+import org.junit.Test;
+
+import java.util.GregorianCalendar;
+
+import static java.util.Calendar.MAY;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.bbottema.javareflection.valueconverter.converters.StringConverters.StringToDateFunction;
+
+public class StringToDateFunctionTest {
+	
+	@Test
+	public void testStringToDateConversion() {
+		final StringToDateFunction converter = new StringToDateFunction();
+		assertThat(converter.apply("2011-5-4")).isEqualTo(new GregorianCalendar(2011, MAY, 4).getTime());
+		assertThat(converter.apply("2011-5-14")).isEqualTo(new GregorianCalendar(2011, MAY, 14).getTime());
+		assertThat(converter.apply("2011-05-4")).isEqualTo(new GregorianCalendar(2011, MAY, 4).getTime());
+		assertThat(converter.apply("2011-05-14")).isEqualTo(new GregorianCalendar(2011, MAY, 14).getTime());
+		assertThat(converter.apply("2011-5-4 05:10")).isEqualTo(new GregorianCalendar(2011, MAY, 4, 5, 10).getTime());
+		assertThat(converter.apply("2011-5-14 05:10")).isEqualTo(new GregorianCalendar(2011, MAY, 14, 5, 10).getTime());
+		assertThat(converter.apply("2011-05-4 05:10")).isEqualTo(new GregorianCalendar(2011, MAY, 4, 5, 10).getTime());
+		assertThat(converter.apply("2011-05-14 05:10")).isEqualTo(new GregorianCalendar(2011, MAY, 14, 5, 10).getTime());
+		assertThat(converter.apply("2011-5-4 5:4")).isEqualTo(new GregorianCalendar(2011, MAY, 4, 5, 4).getTime());
+		assertThat(converter.apply("2011-5-14 5:4")).isEqualTo(new GregorianCalendar(2011, MAY, 14, 5, 4).getTime());
+		assertThat(converter.apply("2011-05-4 5:4")).isEqualTo(new GregorianCalendar(2011, MAY, 4, 5, 4).getTime());
+		assertThat(converter.apply("2011-05-14 5:4")).isEqualTo(new GregorianCalendar(2011, MAY, 14, 5, 4).getTime());
+	}
+}