utility class added required to copy ordering information from one object to another

core/src/main/java/org/acegisecurity/util/OrderedUtils.java

@@ -0,0 +1,65 @@
+package org.acegisecurity.util;
+
+import java.lang.reflect.Method;
+import java.util.Map;
+
+import org.springframework.context.ApplicationContext;
+import org.springframework.core.Ordered;
+import org.springframework.util.Assert;
+import org.springframework.util.ReflectionUtils;
+
+/**
+ * Proivdes common logic for manipulating classes implementing the Spring
+ * {@link Ordered} interface.
+ * 
+ * @author Ben Alex
+ */
+public abstract class OrderedUtils {
+	/**
+	 * Introspects the application context for a single instance of <code>sourceClass</code>. If found, the order from the source
+	 * class instance is copied into the <code>destinationObject</code>. If more than one instance of <code>sourceClass</code>
+	 * is found, the method throws <code>IllegalStateException</code>.
+	 * 
+	 * <p>The <code>destinationObject</code> is required to provide a public <code>setOrder(int)</code> method to permit
+	 * mutation of the order property.
+	 * 
+	 * @param sourceClass to locate in the application context (must be assignable to Ordered)
+	 * @param applicationContext to locate the class
+	 * @param destinationObject to copy the order into (must provide public setOrder(int) method)
+	 * @param skipIfMoreThanOneCandidateSourceClassInstance if the application context provides more than one potential source, skip modifications (if false, the first located matching source will be used)
+	 * @return whether or not the destination class was updated
+	 */
+	public static boolean copyOrderFromOtherClass(Class sourceClass, ApplicationContext applicationContext, Object destinationObject, boolean skipIfMoreThanOneCandidateSourceClassInstance) {
+		Assert.notNull(sourceClass, "Source class required");
+		Assert.notNull(applicationContext, "ApplicationContext required");
+		Assert.notNull(destinationObject, "Destination object required");
+		Assert.isAssignable(Ordered.class, sourceClass, "Source class " + sourceClass + " must be assignable to Ordered");
+		Map map = applicationContext.getBeansOfType(sourceClass);
+		if (map.size() == 0) {
+			return false;
+		} else if (map.size() > 1 && skipIfMoreThanOneCandidateSourceClassInstance) {
+			return false;
+		} else {
+			copyOrderFromOtherObject((Ordered)map.values().iterator().next(), destinationObject);
+			return true;
+		}
+	}
+	
+	/**
+	 * Copies the order property from the <code>sourceObject</code> into the <code>destinationObject</code>.
+	 * 
+	 * <p>The <code>destinationObject</code> is required to provide a public <code>setOrder(int)</code> method to permit
+	 * mutation of the order property.
+	 * 
+	 * @param sourceObject to copy the order from
+	 * @param destinationObject to copy the order into (must provide public setOrder(int) method)
+	 */
+	public static void copyOrderFromOtherObject(Ordered sourceObject, Object destinationObject) {
+		Assert.notNull(sourceObject, "Source object required");
+		Assert.notNull(destinationObject, "Destination object required");
+		Method m = ReflectionUtils.findMethod(destinationObject.getClass(), "setOrder", new Class[] {int.class});
+		Assert.notNull(m, "Method setOrder(int) not found on " + destinationObject.getClass());
+		ReflectionUtils.invokeMethod(m, destinationObject, new Object[] {new Integer(sourceObject.getOrder())});
+	}
+	
+}