Hibernate example source code file (BeanUtils.java)

This example Hibernate source code file (BeanUtils.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

beanutils, exception, field, illegalargumentexception, illegalargumentexception, method, nosuchfieldexception, number, number, object, object, reflection, string, string, stringbuilder

The Hibernate BeanUtils.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2011, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */

package org.hibernate.cache.ehcache.management.impl;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

/**
 * Reflective utilities for dealing with backward-incompatible change to statistics types in Hibernate 3.5.
 *
 * @author gkeim
 */
public class BeanUtils {
	/**
	 * Return the named getter method on the bean or null if not found.
	 *
	 * @param bean
	 * @param propertyName
	 *
	 * @return the named getter method
	 */
	private static Method getMethod(Object bean, String propertyName) {
		StringBuilder sb = new StringBuilder( "get" ).append( Character.toUpperCase( propertyName.charAt( 0 ) ) );
		if ( propertyName.length() > 1 ) {
			sb.append( propertyName.substring( 1 ) );
		}
		String getterName = sb.toString();
		for ( Method m : bean.getClass().getMethods() ) {
			if ( getterName.equals( m.getName() ) && m.getParameterTypes().length == 0 ) {
				return m;
			}
		}
		return null;
	}

	/**
	 * Return the named field on the bean or null if not found.
	 *
	 * @param bean
	 * @param propertyName
	 *
	 * @return the named field
	 */
	private static Field getField(Object bean, String propertyName) {
		for ( Field f : bean.getClass().getDeclaredFields() ) {
			if ( propertyName.equals( f.getName() ) ) {
				return f;
			}
		}
		return null;
	}

	private static void validateArgs(Object bean, String propertyName) {
		if ( bean == null ) {
			throw new IllegalArgumentException( "bean is null" );
		}
		if ( propertyName == null ) {
			throw new IllegalArgumentException( "propertyName is null" );
		}
		if ( propertyName.trim().length() == 0 ) {
			throw new IllegalArgumentException( "propertyName is empty" );
		}
	}

	/**
	 * Retrieve a named bean property value.
	 *
	 * @param bean bean
	 * @param propertyName
	 *
	 * @return the property value
	 */
	public static Object getBeanProperty(Object bean, String propertyName) {
		validateArgs( bean, propertyName );

		// try getters first
		Method getter = getMethod( bean, propertyName );
		if ( getter != null ) {
			try {
				return getter.invoke( bean );
			}
			catch ( Exception e ) {
				/**/
			}
		}

		// then try fields
		Field field = getField( bean, propertyName );
		if ( field != null ) {
			try {
				field.setAccessible( true );
				return field.get( bean );
			}
			catch ( Exception e ) {
				/**/
			}
		}

		return null;
	}

	/**
	 * Retrieve a Long bean property value.
	 *
	 * @param bean bean
	 * @param propertyName
	 *
	 * @return long value
	 *
	 * @throws NoSuchFieldException
	 */
	public static long getLongBeanProperty(final Object bean, final String propertyName) throws NoSuchFieldException {
		validateArgs( bean, propertyName );
		Object o = getBeanProperty( bean, propertyName );
		if ( o == null ) {
			throw new NoSuchFieldException( propertyName );
		}
		else if ( !( o instanceof Number ) ) {
			throw new IllegalArgumentException( propertyName + " not an Number" );
		}
		return ( (Number) o ).longValue();
	}
}