ExitOperationUtils.java

/*
 * @(#)ExitOperationUtils.java 2012-8-1 下午10:00:00
 *
 * Copyright (c) 2011-2012 Makersoft.org all rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 *
 */
package org.makersoft.shards.strategy.exit;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;

import org.makersoft.shards.utils.Lists;
import org.makersoft.shards.utils.StringUtil;

/**
 * @author Maulik Shah
 */
public class ExitOperationUtils {

	public static List<Object> getNonNullList(List<Object> list) {
		List<Object> nonNullList = Lists.newArrayList();
		for (Object obj : list) {
			if (obj != null) {
				nonNullList.add(obj);
			}
		}
		return nonNullList;
	}

	@SuppressWarnings({ "rawtypes", "unchecked" })
	public static List<Comparable<Object>> getComparableList(
			List<Object> results) {
		List<Comparable<Object>> result = (List<Comparable<Object>>) (List) results;
		return result;
	}

	@SuppressWarnings({ "rawtypes", "unchecked" })
	public static Comparable<Object> getPropertyValue(Object obj,
			String propertyName) {
		/**
		 * TODO(maulik) respect the client's choice in how Hibernate accesses
		 * property values.
		 * 
		 * Currently this method access members of an object using getters only,
		 * event of the client has specifed to use direct field access. Ideally,
		 * we could get an EntityPersister from the SessionFactoryImplementor
		 * and use that. However, hibernate's EntityPersister expects all
		 * properties to be a ComponentType. In pratice, these objects are
		 * interconnected in the mapping and Hibernate instantiates them as
		 * BagType or ManyToOneType, i.e. as they are specified in the mappings.
		 * Hence, we cannot use Hibernate's EntityPersister.
		 */

		try {
			StringBuilder propertyPath = new StringBuilder();
			for (int i = 0; i < propertyName.length(); i++) {
				String s = propertyName.substring(i, i + 1);
				if (i == 0 || propertyName.charAt(i - 1) == '.') {
					propertyPath.append(StringUtil.capitalize(s));
				} else {
					propertyPath.append(s);
				}
			}
			String[] methods = ("get" + propertyPath.toString().replaceAll(
					"\\.", ".get")).split("\\.");
			Object root = obj;
			for (String method : methods) {
				Class clazz = root.getClass();
				Method m = clazz.getMethod(method);
				root = m.invoke(root);
				if (root == null) {
					break;
				}
			}

			Comparable<Object> result = (Comparable<Object>) root;
			return result;
		} catch (NoSuchMethodException e) {
			throw new RuntimeException(e);
		} catch (IllegalAccessException e) {
			throw new RuntimeException(e);
		} catch (InvocationTargetException e) {
			throw new RuntimeException(e);
		}
	}

}