javadoc and tests for flow/view variables

spring-webflow/src/main/java/org/springframework/webflow/engine/FlowVariable.java

@@ -20,8 +20,9 @@ import org.springframework.util.Assert;
 import org.springframework.webflow.execution.RequestContext;
 
 /**
- * A value object that defines a specification for a flow variable. Encapsulates information about the variable and the
- * behavior necessary to create a new variable instance in a flow execution scope.
+ * A value object that defines a specification for a flow variable. Such a variable is allocated when a flow starts and
+ * destroyed when that flow ends. This class encapsulates information about the variable and the behavior necessary to
+ * allocate the variable instance in flow scope.
  * 
  * @author Keith Donald
  */
@@ -84,8 +85,12 @@ public class FlowVariable extends AnnotatedObject {
 		return name.hashCode() + valueFactory.hashCode() + local.hashCode();
 	}
 
-	public final void create(RequestContext context) {
-		Object value = valueFactory.createVariableValue(context);
+	/**
+	 * Creates this flow variable. This method allocates the variable's value in the correct flow scope.
+	 * @param context the executing flow
+	 */
+	public void create(RequestContext context) {
+		Object value = valueFactory.createInitialValue(context);
 		if (local == Boolean.TRUE) {
 			context.getFlowScope().put(name, value);
 		} else {
@@ -93,14 +98,31 @@ public class FlowVariable extends AnnotatedObject {
 		}
 	}
 
-	public final Object restore(RequestContext context) {
+	/**
+	 * Restores this variable's dependencies. This method asks the variable's value factory to restore any references
+	 * the variable has to transient objects.
+	 * @param context the executing flow
+	 */
+	public void restore(RequestContext context) {
 		Object value;
 		if (local == Boolean.TRUE) {
 			value = context.getFlowScope().get(name);
 		} else {
 			value = context.getConversationScope().get(name);
 		}
-		return valueFactory.restoreReferences(value, context);
+		valueFactory.restoreReferences(value, context);
+	}
+
+	/**
+	 * Destroys this flow variable. This method removes the variable's value in the correct flow scope.
+	 * @param context the executing flow
+	 */
+	public Object destroy(RequestContext context) {
+		if (local == Boolean.TRUE) {
+			return context.getFlowScope().remove(name);
+		} else {
+			return context.getConversationScope().remove(name);
+		}
 	}
 
 	public String toString() {

spring-webflow/src/main/java/org/springframework/webflow/engine/VariableValueFactory.java

@@ -2,8 +2,24 @@ package org.springframework.webflow.engine;
 
 import org.springframework.webflow.execution.RequestContext;
 
+/**
+ * A strategy that encapsulates the source of a flow variable value.
+ * @author Keith Donald
+ */
 public interface VariableValueFactory {
-	public Object createVariableValue(RequestContext context);
 
-	public Object restoreReferences(Object value, RequestContext context);
+	/**
+	 * Creates the variable's initial value.
+	 * @param context the currently executing flow request
+	 * @return the value
+	 */
+	public Object createInitialValue(RequestContext context);
+
+	/**
+	 * Restore any references the variable's value needs to other objects. Such references may have been lost during
+	 * deserialization, for example, and need to be restored.
+	 * @param value the current variable value
+	 * @param context the currently executing flow request
+	 */
+	public void restoreReferences(Object value, RequestContext context);
 }

spring-webflow/src/main/java/org/springframework/webflow/engine/ViewVariable.java

@@ -2,20 +2,38 @@ package org.springframework.webflow.engine;
 
 import org.springframework.webflow.execution.RequestContext;
 
+/**
+ * A variable scoped to a particular view. Such a variable is allocated when a view-state is entered and destroyed when
+ * that view-state exits. The flow scope map is used as the backing variable store.
+ * 
+ * @author Keith Donald
+ */
 public class ViewVariable extends AnnotatedObject {
+
 	private String name;
 
 	private VariableValueFactory valueFactory;
 
+	/**
+	 * Creates a new view variable.
+	 * @param name the name of the variable
+	 * @param valueFactory the source for the variable value
+	 */
 	public ViewVariable(String name, VariableValueFactory valueFactory) {
 		this.name = name;
 		this.valueFactory = valueFactory;
 	}
 
+	/**
+	 * Returns the name of this view variable.
+	 */
 	public String getName() {
 		return name;
 	}
 
+	/**
+	 * Returns the source of the variable's initial value.
+	 */
 	public VariableValueFactory getValueFactory() {
 		return valueFactory;
 	}
@@ -34,17 +52,30 @@ public class ViewVariable extends AnnotatedObject {
 		return name.hashCode() + valueFactory.hashCode();
 	}
 
-	public final void create(RequestContext context) {
-		Object value = valueFactory.createVariableValue(context);
+	/**
+	 * Creates this view variable. This method allocates the variable's value in flow scope.
+	 * @param context the executing flow
+	 */
+	public void create(RequestContext context) {
+		Object value = valueFactory.createInitialValue(context);
 		context.getFlowScope().put(name, value);
 	}
 
-	public final Object restore(RequestContext context) {
+	/**
+	 * Restores this view variable's dependencies. This method asks the variable's value factory to restore any
+	 * references the variable has to transient objects.
+	 * @param context the executing flow
+	 */
+	public void restore(RequestContext context) {
 		Object value = context.getFlowScope().get(name);
-		return valueFactory.restoreReferences(value, context);
+		valueFactory.restoreReferences(value, context);
 	}
 
-	public final Object destroy(RequestContext context) {
+	/**
+	 * Destroy this view variable. This method removes the variable's value in flow scope.
+	 * @param context the executing flow
+	 */
+	public Object destroy(RequestContext context) {
 		return context.getFlowScope().remove(name);
 	}
 }

spring-webflow/src/main/java/org/springframework/webflow/engine/support/BeanFactoryVariableValueFactory.java

@@ -16,27 +16,48 @@
 package org.springframework.webflow.engine.support;
 
 import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
+import org.springframework.core.style.ToStringCreator;
 import org.springframework.webflow.engine.VariableValueFactory;
 import org.springframework.webflow.execution.RequestContext;
 
+/**
+ * A bean-factory backed variable value factory. Relies on an autowire-capable bean factory to wire variable value
+ * dependencies on value creation and restoration.
+ * 
+ * @author Keith Donald
+ */
 public class BeanFactoryVariableValueFactory implements VariableValueFactory {
 
+	/**
+	 * The class of variable value. Typically a Java bean.
+	 */
 	private Class type;
 
+	/**
+	 * The backing bean factory that will create and restore variable instances.
+	 */
 	private AutowireCapableBeanFactory beanFactory;
 
+	/**
+	 * Creates a new bean factory variable factory.
+	 * @param type the variable class
+	 * @param beanFactory the bean factory that will create and restore variable instances.
+	 */
 	public BeanFactoryVariableValueFactory(Class type, AutowireCapableBeanFactory beanFactory) {
 		this.type = type;
 		this.beanFactory = beanFactory;
 	}
 
-	public Object createVariableValue(RequestContext context) {
+	public Object createInitialValue(RequestContext context) {
 		return beanFactory.createBean(type);
 	}
 
-	public Object restoreReferences(Object value, RequestContext context) {
+	public void restoreReferences(Object value, RequestContext context) {
 		beanFactory.autowireBean(value);
-		return value;
+	}
+
+	public String toString() {
+		return new ToStringCreator(this).append("type").append(type).toString();
 	}
 
 }

spring-webflow/src/test/java/org/springframework/webflow/engine/FlowTests.java

@@ -182,12 +182,11 @@ public class FlowTests extends TestCase {
 	public void testStartWithVariables() {
 		MockRequestControlContext context = new MockRequestControlContext(flow);
 		flow.addVariable(new FlowVariable("var1", new VariableValueFactory() {
-			public Object createVariableValue(RequestContext context) {
+			public Object createInitialValue(RequestContext context) {
 				return new ArrayList();
 			}
 
-			public Object restoreReferences(Object value, RequestContext context) {
-				return value;
+			public void restoreReferences(Object value, RequestContext context) {
 			}
 		}, true));
 		flow.start(context, new LocalAttributeMap());

spring-webflow/src/test/java/org/springframework/webflow/engine/FlowVariableTests.java

@@ -11,28 +11,41 @@ public class FlowVariableTests extends TestCase {
 
 	public void testCreateVariable() {
 		FlowVariable var = new FlowVariable("foo", new VariableValueFactory() {
-			public Object createVariableValue(RequestContext context) {
+			public Object createInitialValue(RequestContext context) {
 				return "bar";
 			}
 
-			public Object restoreReferences(Object value, RequestContext context) {
-				return value;
+			public void restoreReferences(Object value, RequestContext context) {
 			}
-
 		}, true);
 		MockRequestContext context = new MockRequestContext();
 		var.create(context);
 		assertEquals("bar", context.getFlowScope().get("foo"));
 	}
 
-	public void testCreateConversationVariable() {
+	public void testDestroyVariable() {
 		FlowVariable var = new FlowVariable("foo", new VariableValueFactory() {
-			public Object createVariableValue(RequestContext context) {
+			public Object createInitialValue(RequestContext context) {
 				return "bar";
 			}
 
-			public Object restoreReferences(Object value, RequestContext context) {
-				return value;
+			public void restoreReferences(Object value, RequestContext context) {
+			}
+		}, true);
+		MockRequestContext context = new MockRequestContext();
+		var.create(context);
+		assertEquals("bar", context.getFlowScope().get("foo"));
+		var.destroy(context);
+		assertFalse(context.getFlowScope().contains("foo"));
+	}
+
+	public void testCreateConversationVariable() {
+		FlowVariable var = new FlowVariable("foo", new VariableValueFactory() {
+			public Object createInitialValue(RequestContext context) {
+				return "bar";
+			}
+
+			public void restoreReferences(Object value, RequestContext context) {
 			}
 		}, false);
 		MockRequestContext context = new MockRequestContext();
@@ -40,16 +53,31 @@ public class FlowVariableTests extends TestCase {
 		assertEquals("bar", context.getConversationScope().get("foo"));
 	}
 
-	public void testCreateRestoreVariable() {
+	public void testDestroyConversationVariable() {
 		FlowVariable var = new FlowVariable("foo", new VariableValueFactory() {
-			public Object createVariableValue(RequestContext context) {
+			public Object createInitialValue(RequestContext context) {
 				return "bar";
 			}
 
-			public Object restoreReferences(Object value, RequestContext context) {
+			public void restoreReferences(Object value, RequestContext context) {
+			}
+		}, false);
+		MockRequestContext context = new MockRequestContext();
+		var.create(context);
+		assertEquals("bar", context.getConversationScope().get("foo"));
+		var.destroy(context);
+		assertFalse(context.getConversationScope().contains("foo"));
+	}
+
+	public void testRestoreVariable() {
+		FlowVariable var = new FlowVariable("foo", new VariableValueFactory() {
+			public Object createInitialValue(RequestContext context) {
+				return "bar";
+			}
+
+			public void restoreReferences(Object value, RequestContext context) {
 				restoreCalled = true;
 				assertEquals("bar", value);
-				return value;
 			}
 		}, false);
 		MockRequestContext context = new MockRequestContext();
@@ -58,4 +86,5 @@ public class FlowVariableTests extends TestCase {
 		assertEquals("bar", context.getConversationScope().get("foo"));
 		assertTrue(restoreCalled);
 	}
+
 }

spring-webflow/src/test/java/org/springframework/webflow/engine/support/BeanFactoryVariableValueFactoryTests.java

@@ -12,7 +12,14 @@ public class BeanFactoryVariableValueFactoryTests extends TestCase {
 	public void testCreateValue() {
 		factory = new BeanFactoryVariableValueFactory(TestBean.class, new DefaultListableBeanFactory());
 		MockRequestContext context = new MockRequestContext();
-		Object value = factory.createVariableValue(context);
+		Object value = factory.createInitialValue(context);
 		assertTrue(value instanceof TestBean);
 	}
+
+	public void testRestoreValue() {
+		factory = new BeanFactoryVariableValueFactory(TestBean.class, new DefaultListableBeanFactory());
+		MockRequestContext context = new MockRequestContext();
+		TestBean bean = new TestBean();
+		factory.restoreReferences(bean, context);
+	}
 }