factored out alert from message; made binding responsible for alert generation

Author: Keith Donald

org.springframework.context/src/main/java/org/springframework/ui/alert/Alert.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2004-2009 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.ui.alert;
+
+/**
+ * Communicates an event of interest to the user.
+ * For example, an alert may inform a user of a web application a business rule was violated.
+ * TODO - should we introduce detail messages here
+ * @author Keith Donald
+ * @since 3.0
+ */
+public interface Alert {
+
+	/**
+	 * The user interface element this alert is associated with; for example, "registration.password"
+	 */
+	public String getElement();
+
+	/**
+	 * The code uniquely identifying this kind of alert; for example, "weakPassword".
+	 * May be used as a key to lookup additional alert details.
+	 */
+	public String getCode();
+
+	/**
+	 * The level of impact this alert has on the user.
+	 */
+	public Severity getSeverity();
+
+	/**
+	 * The localized message to display to the user; for example, "Please enter a stronger password".
+	 */
+	public String getMessage();
+
+}

org.springframework.context/src/main/java/org/springframework/ui/alert/AlertContext.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2004-2009 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.ui.alert;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A context for adding and getting alerts for display in a user interface.
+ * @author Keith Donald
+ * @since 3.0
+ */
+public interface AlertContext {
+
+	/**
+	 * Return all alerts in this context indexed by the UI element they are associated with.
+	 * @return the message map
+	 */
+	public Map<String, List<Alert>> getAlerts();
+	
+	/**
+	 * Get all alerts on the UI element provided.
+	 * Returns an empty list if no alerts have been added for the element.
+	 * Alerts are returned in the order they were added.
+	 * @param element the id of the element to lookup alerts against
+	 */
+	public List<Alert> getAlerts(String element);
+
+	/**
+	 * Add an alert to this context.
+	 * @param alert the alert to add
+	 */
+	public void add(Alert alert);
+
+}

org.springframework.context/src/main/java/org/springframework/ui/message/Severity.java renamed to org.springframework.context/src/main/java/org/springframework/ui/alert/Severity.java

@@ -13,14 +13,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.springframework.ui.message;
+package org.springframework.ui.alert;
 
 /**
- * Enum exposing supported message severities.
- * 
+ * The set of alert severities.
  * @author Keith Donald
  * @since 3.0 
- * @see Message
+ * @see Alert
  */
 public enum Severity {
 
@@ -30,7 +29,7 @@ public enum Severity {
 	INFO,
 
 	/**
-	 * The "Warning" severity. Used to indicate there is a minor problem, or to inform the message receiver of possible
+	 * The "Warning" severity. Used to indicate there is a minor problem, or to inform the user of possible
 	 * misuse, or to indicate a problem may arise in the future.
 	 */
 	WARNING,
@@ -41,7 +40,7 @@ public enum Severity {
 	ERROR,
 
 	/**
-	 * The "Fatal" severity. Used to indicate a fatal problem like a system error.
+	 * The "Fatal" severity. Used to indicate a fatal problem like a system error or runtime exception.
 	 */
 	FATAL
 

org.springframework.context/src/main/java/org/springframework/ui/alert/package.html

@@ -0,0 +1,7 @@
+<html>
+<body>
+<p>
+An API for alerts to display in a user interface.
+</p>
+</body>
+</html>

org.springframework.context/src/main/java/org/springframework/ui/alert/support/DefaultAlertContext.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2004-2009 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.ui.alert.support;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.core.style.ToStringCreator;
+import org.springframework.ui.alert.Alert;
+import org.springframework.ui.alert.AlertContext;
+import org.springframework.util.CachingMapDecorator;
+
+/**
+ * The default alert context implementation.
+ * @author Keith Donald
+ * @since 3.0
+ */
+public class DefaultAlertContext implements AlertContext {
+
+	@SuppressWarnings("serial")
+	private Map<String, List<Alert>> alertsByElement = new CachingMapDecorator<String, List<Alert>>(new LinkedHashMap<String, List<Alert>>()) {
+		protected List<Alert> create(String element) {
+			return new ArrayList<Alert>();
+		}
+	};
+
+	// implementing AlertContext
+
+	public Map<String, List<Alert>> getAlerts() {
+		return Collections.unmodifiableMap(alertsByElement);
+	}
+	
+	public List<Alert> getAlerts(String element) {
+		List<Alert> messages = alertsByElement.get(element);
+		if (messages.isEmpty()) {
+			return Collections.emptyList();
+		}
+		return Collections.unmodifiableList(messages);
+	}
+
+	public void add(Alert alert) {
+		List<Alert> alerts = alertsByElement.get(alert.getElement());
+		alerts.add(alert);
+	}
+
+	public String toString() {
+		return new ToStringCreator(this).append("alertsByElement", alertsByElement).toString();
+	}
+
+}

org.springframework.context/src/main/java/org/springframework/ui/alert/support/package.html

@@ -0,0 +1,7 @@
+<html>
+<body>
+<p>
+Support implementation of the Alert API.
+</p>
+</body>
+</html>

org.springframework.context/src/main/java/org/springframework/ui/binding/BindingResult.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.ui.binding;
 
+import org.springframework.ui.alert.Alert;
+
 /**
  * The result of a bind operation.
  * @author Keith Donald
@@ -28,32 +30,24 @@ public interface BindingResult {
 	 * The name of the model property associated with this binding result.
 	 */
 	String getProperty();
-	
-	/**
-	 * Indicates if this result is an error result.
-	 */
-	boolean isError();
-
-	/**
-	 * If an error result, the error code; for example, "invalidFormat" or "propertyNotFound".
-	 */
-	String getErrorCode();
 
 	/**
-	 * If an error, result returns a default message describing what went wrong.
+	 * The raw user-entered value for which binding was attempted.
+	 * If not a failure, this value was successfully bound to the model.
+	 * @see #isFailure()
 	 */
-	String getErrorMessage();
-
-
+	Object getUserValue();
+	
 	/**
-	 * If an error result, the cause of the error.
+	 * Indicates if the binding failed.
 	 */
-	Throwable getErrorCause();
+	boolean isFailure();
 
 	/**
-	 * The raw user-entered value for which binding was attempted.
-	 * If not an error result, this value was successfully bound to the model.
+	 * Gets the alert for this binding result, appropriate for rendering the result to the user.
+	 * An alert describing a successful binding will have info severity.
+	 * An alert describing a failed binding will have either warning, error, or fatal severity.
 	 */
-	Object getUserValue();
+	Alert getAlert();
 
 }

org.springframework.context/src/main/java/org/springframework/ui/binding/Bound.java

@@ -0,0 +1,14 @@
+package org.springframework.ui.binding;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target({ElementType.METHOD})
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface Bound {
+
+}

org.springframework.context/src/main/java/org/springframework/ui/binding/Model.java

@@ -0,0 +1,25 @@
+package org.springframework.ui.binding;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target({ElementType.TYPE})
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface Model {
+
+	/**
+	 * The name of the model
+	 */
+	String value() default "";
+
+	/**
+	 * Configures strict model binding.
+	 * @see Binder#setStrict(boolean)
+	 */
+	boolean strict() default false;
+
+}