Added conversion support for Java 8's ZoneId class and the 'of' method convention

Issue: SPR-1528

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/PropertyEditorRegistrySupport.java

@@ -65,6 +65,7 @@
 import org.springframework.beans.propertyeditors.URIEditor;
 import org.springframework.beans.propertyeditors.URLEditor;
 import org.springframework.beans.propertyeditors.UUIDEditor;
+import org.springframework.beans.propertyeditors.ZoneIdEditor;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.ResourceArrayPropertyEditor;
@@ -84,6 +85,19 @@
  */
 public class PropertyEditorRegistrySupport implements PropertyEditorRegistry {
 
+	private static Class<?> zoneIdClass;
+
+	static {
+		try {
+			zoneIdClass = PropertyEditorRegistrySupport.class.getClassLoader().loadClass("java.time.ZoneId");
+		}
+		catch (ClassNotFoundException ex) {
+			// Java 8 ZoneId class not available
+			zoneIdClass = null;
+		}
+	}
+
+
 	private ConversionService conversionService;
 
 	private boolean defaultEditorsActive = false;
@@ -202,6 +216,9 @@ private void createDefaultEditors() {
 		this.defaultEditors.put(URI.class, new URIEditor());
 		this.defaultEditors.put(URL.class, new URLEditor());
 		this.defaultEditors.put(UUID.class, new UUIDEditor());
+		if (zoneIdClass != null) {
+			this.defaultEditors.put(zoneIdClass, new ZoneIdEditor());
+		}
 
 		// Default instances of collection editors.
 		// Can be overridden by registering custom instances of those as custom editors.

spring-beans/src/main/java/org/springframework/beans/propertyeditors/TimeZoneEditor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,11 +21,12 @@
 
 /**
  * Editor for {@code java.util.TimeZone}, translating timezone IDs into
- * TimeZone objects. Does not expose a text representation for TimeZone objects.
+ * TimeZone objects. Exposed the TimeZone ID as a text representation.
  *
  * @author Juergen Hoeller
  * @since 3.0
  * @see java.util.TimeZone
+ * @see ZoneIdEditor
  */
 public class TimeZoneEditor extends PropertyEditorSupport {
 
@@ -34,13 +35,10 @@ public void setAsText(String text) throws IllegalArgumentException {
 		setValue(TimeZone.getTimeZone(text));
 	}
 
-	/**
-	 * This implementation returns {@code null} to indicate that
-	 * there is no appropriate text representation.
-	 */
 	@Override
 	public String getAsText() {
-		return null;
+		TimeZone value = (TimeZone) getValue();
+		return (value != null ? value.getID() : "");
 	}
 
 }

spring-beans/src/main/java/org/springframework/beans/propertyeditors/ZoneIdEditor.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2002-2013 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.propertyeditors;
+
+import java.beans.PropertyEditorSupport;
+import java.time.ZoneId;
+
+/**
+ * Editor for {@code java.time.ZoneId}, translating zone ID Strings into
+ * ZoneId objects. Exposed the TimeZone ID as a text representation.
+ *
+ * @author Juergen Hoeller
+ * @since 4.0
+ * @see java.time.ZoneId
+ * @see TimeZoneEditor
+ */
+public class ZoneIdEditor extends PropertyEditorSupport {
+
+	@Override
+	public void setAsText(String text) throws IllegalArgumentException {
+		setValue(ZoneId.of(text));
+	}
+
+	@Override
+	public String getAsText() {
+		ZoneId value = (ZoneId) getValue();
+		return (value != null ? value.getId() : "");
+	}
+
+}

spring-core/src/main/java/org/springframework/core/convert/support/ObjectToObjectConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,13 +29,13 @@
 import org.springframework.util.ReflectionUtils;
 
 /**
- * Generic Converter that attempts to convert a source Object to a target type
+ * Generic converter that attempts to convert a source Object to a target type
  * by delegating to methods on the target type.
  *
- * <p>Calls the static {@code valueOf(sourceType)} method on the target type
- * to perform the conversion, if such a method exists. Else calls the target type's
- * Constructor that accepts a single sourceType argument, if such a Constructor exists.
- * Else throws a ConversionFailedException.
+ * <p>Calls a static {@code valueOf(sourceType)} or Java 8 style {@code of(sourceType)} method
+ * on the target type to perform the conversion, if such a method exists. Otherwise, it calls
+ * the target type's constructor that accepts a single {@code sourceType} argument, if such
+ * a constructor exists. If neither strategy works, it throws a ConversionFailedException.
  *
  * @author Keith Donald
  * @author Juergen Hoeller
@@ -92,7 +92,11 @@ static boolean hasValueOfMethodOrConstructor(Class<?> clazz, Class<?> sourcePara
 	}
 
 	private static Method getValueOfMethodOn(Class<?> clazz, Class<?> sourceParameterType) {
-		return ClassUtils.getStaticMethod(clazz, "valueOf", sourceParameterType);
+		Method method = ClassUtils.getStaticMethod(clazz, "valueOf", sourceParameterType);
+		if (method == null) {
+			method = ClassUtils.getStaticMethod(clazz, "of", sourceParameterType);
+		}
+		return method;
 	}
 
 	private static Constructor<?> getConstructor(Class<?> clazz, Class<?> sourceParameterType) {

spring-core/src/test/java/org/springframework/core/convert/support/DefaultConversionTests.java

@@ -16,19 +16,10 @@
 
 package org.springframework.core.convert.support;
 
-import static org.hamcrest.Matchers.equalTo;
-import static org.junit.Assert.*;
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThat;
-import static org.junit.Assert.assertTrue;
-
 import java.awt.Color;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.time.ZoneId;
 import java.util.AbstractList;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -45,13 +36,17 @@
 import java.util.Set;
 
 import org.junit.Test;
+
 import org.springframework.core.MethodParameter;
 import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.ConverterNotFoundException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.converter.ConverterRegistry;
 
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
 /**
  * @author Keith Donald
  * @author Juergen Hoeller
@@ -709,6 +704,11 @@ public void convertObjectToStringStringConstructorPresent() {
 		assertEquals("123456789", conversionService.convert(new SSN("123456789"), String.class));
 	}
 
+	@Test
+	public void convertObjectToStringWithJavaTimeOfMethodPresent() {
+		assertTrue(conversionService.convert(ZoneId.of("GMT+1"), String.class).startsWith("GMT+"));
+	}
+
 	@Test
 	public void convertObjectToStringNotSupported() {
 		assertFalse(conversionService.canConvert(TestEntity.class, String.class));
@@ -725,73 +725,16 @@ public void convertObjectToObjectConstructor() {
 		assertEquals("123456789", conversionService.convert(new SSN("123456789"), String.class));
 	}
 
+	@Test
+	public void convertObjectToObjectWithJavaTimeOfMethod() {
+		assertEquals(ZoneId.of("GMT+1"), conversionService.convert("GMT+1", ZoneId.class));
+	}
+
 	@Test(expected=ConverterNotFoundException.class)
 	public void convertObjectToObjectNoValueOFMethodOrConstructor() {
 		conversionService.convert(new Long(3), SSN.class);
 	}
 
-	public Object assignableTarget;
-
-	private static class SSN {
-
-		private String value;
-
-		public SSN(String value) {
-			this.value = value;
-		}
-
-		@Override
-		public boolean equals(Object o) {
-			if (!(o instanceof SSN)) {
-				return false;
-			}
-			SSN ssn = (SSN) o;
-			return this.value.equals(ssn.value);
-		}
-
-		@Override
-		public int hashCode() {
-			return value.hashCode();
-		}
-
-		@Override
-		public String toString() {
-			return value;
-		}
-	}
-
-	private static class ISBN {
-
-		private String value;
-
-		private ISBN(String value) {
-			this.value = value;
-		}
-
-		@Override
-		public boolean equals(Object o) {
-			if (!(o instanceof ISBN)) {
-				return false;
-			}
-			ISBN isbn = (ISBN) o;
-			return this.value.equals(isbn.value);
-		}
-
-		@Override
-		public int hashCode() {
-			return value.hashCode();
-		}
-
-		@Override
-		public String toString() {
-			return value;
-		}
-
-		public static ISBN valueOf(String value) {
-			return new ISBN(value);
-		}
-	}
-
 	@Test
 	public void convertObjectToObjectFinderMethod() {
 		TestEntity e = conversionService.convert(1L, TestEntity.class);
@@ -864,4 +807,66 @@ public List<?> getList() {
 		}
 	}
 
+	public Object assignableTarget;
+
+	private static class SSN {
+
+		private String value;
+
+		public SSN(String value) {
+			this.value = value;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (!(o instanceof SSN)) {
+				return false;
+			}
+			SSN ssn = (SSN) o;
+			return this.value.equals(ssn.value);
+		}
+
+		@Override
+		public int hashCode() {
+			return value.hashCode();
+		}
+
+		@Override
+		public String toString() {
+			return value;
+		}
+	}
+
+	private static class ISBN {
+
+		private String value;
+
+		private ISBN(String value) {
+			this.value = value;
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (!(o instanceof ISBN)) {
+				return false;
+			}
+			ISBN isbn = (ISBN) o;
+			return this.value.equals(isbn.value);
+		}
+
+		@Override
+		public int hashCode() {
+			return value.hashCode();
+		}
+
+		@Override
+		public String toString() {
+			return value;
+		}
+
+		public static ISBN valueOf(String value) {
+			return new ISBN(value);
+		}
+	}
+
 }