Add test cases and re-org packages

src/main/java/org/springframework/classify/SubclassClassifier.java

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+/*
+ * Copyright 2006-2007 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.classify;
+
+import java.io.Serializable;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
+
+/**
+ * A {@link Classifier} for a parameterised object type based on a map.
+ * Classifies objects according to their inheritance relation with the supplied
+ * type map. If the object to be classified is one of the keys of the provided
+ * map, or is a subclass of one of the keys, then the map entry value for that
+ * key is returned. Otherwise returns the default value which is null by
+ * default.
+ * 
+ * @author Dave Syer
+ * 
+ */
+public class SubclassClassifier<T, C> implements Classifier<T, C> {
+
+	private Map<Class<? extends T>, C> classified = new HashMap<Class<? extends T>, C>();
+
+	private C defaultValue = null;
+
+	/**
+	 * Create a {@link SubclassClassifier} with null default value.
+	 * 
+	 */
+	public SubclassClassifier() {
+		this(null);
+	}
+
+	/**
+	 * Create a {@link SubclassClassifier} with supplied default value.
+	 * 
+	 * @param defaultValue
+	 */
+	public SubclassClassifier(C defaultValue) {
+		this(new HashMap<Class<? extends T>, C>(), defaultValue);
+	}
+
+	/**
+	 * Create a {@link SubclassClassifier} with supplied default value.
+	 * 
+	 * @param defaultValue
+	 */
+	public SubclassClassifier(Map<Class<? extends T>, C> typeMap, C defaultValue) {
+		super();
+		this.classified = new HashMap<Class<? extends T>, C>(typeMap);
+		this.defaultValue = defaultValue;
+	}
+
+	/**
+	 * Public setter for the default value for mapping keys that are not found
+	 * in the map (or their subclasses). Defaults to false.
+	 * 
+	 * @param defaultValue the default value to set
+	 */
+	public void setDefaultValue(C defaultValue) {
+		this.defaultValue = defaultValue;
+	}
+
+	/**
+	 * Set the classifications up as a map. The keys are types and these will be
+	 * mapped along with all their subclasses to the corresponding value. The
+	 * most specific types will match first.
+	 * 
+	 * @param map a map from type to class
+	 */
+	public void setTypeMap(Map<Class<? extends T>, C> map) {
+		this.classified = new HashMap<Class<? extends T>, C>(map);
+	}
+
+	/**
+	 * Return the value from the type map whose key is the class of the given
+	 * Throwable, or its nearest ancestor if a subclass.
+	 * 
+	 */
+	public C classify(T classifiable) {
+
+		if (classifiable == null) {
+			return defaultValue;
+		}
+
+		@SuppressWarnings("unchecked")
+		Class<? extends T> exceptionClass = (Class<? extends T>) classifiable.getClass();
+		if (classified.containsKey(exceptionClass)) {
+			return classified.get(exceptionClass);
+		}
+
+		// check for subclasses
+		Set<Class<? extends T>> classes = new TreeSet<Class<? extends T>>(new ClassComparator());
+		classes.addAll(classified.keySet());
+		for (Class<? extends T> cls : classes) {
+			if (cls.isAssignableFrom(exceptionClass)) {
+				C value = classified.get(cls);
+				this.classified.put(exceptionClass, value);
+				return value;
+			}
+		}
+
+		return defaultValue;
+	}
+
+	/**
+	 * Return the default value supplied in the constructor (default false).
+	 */
+	final public C getDefault() {
+		return defaultValue;
+	}
+
+	/**
+	 * Comparator for classes to order by inheritance.
+	 * 
+	 * @author Dave Syer
+	 * 
+	 */
+	private static class ClassComparator implements Comparator<Class<?>>, Serializable {
+		/**
+		 * @return 1 if arg0 is assignable from arg1, -1 otherwise
+		 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
+		 */
+		public int compare(Class<?> arg0, Class<?> arg1) {
+			if (arg0.isAssignableFrom(arg1)) {
+				return 1;
+			}
+			return -1;
+		}
+	}
+
+}