basicpropertyaccessor.java

一个Java持久层类库

//$Id: BasicPropertyAccessor.java 7516 2005-07-16 22:20:48Z oneovthafew $
package org.hibernate.property;

import java.beans.Introspector;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.hibernate.HibernateException;
import org.hibernate.PropertyAccessException;
import org.hibernate.PropertyNotFoundException;
import org.hibernate.engine.SessionFactoryImplementor;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.util.ReflectHelper;

/**
 * Accesses property values via a get/set pair, which may be nonpublic.
 * The default (and recommended strategy).
 * @author Gavin King
 */
public class BasicPropertyAccessor implements PropertyAccessor {

	private static final Logger log = LoggerFactory.getLogger(BasicPropertyAccessor.class);

	public static final class BasicSetter implements Setter {
		private Class clazz;
		private final transient Method method;
		private final String propertyName;

		private BasicSetter(Class clazz, Method method, String propertyName) {
			this.clazz=clazz;
			this.method=method;
			this.propertyName=propertyName;
		}

		public void set(Object target, Object value, SessionFactoryImplementor factory) 
		throws HibernateException {
			try {
				method.invoke( target, new Object[] { value } );
			}
			catch (NullPointerException npe) {
				if ( value==null && method.getParameterTypes()[0].isPrimitive() ) {
					throw new PropertyAccessException(
							npe, 
							"Null value was assigned to a property of primitive type", 
							true, 
							clazz, 
							propertyName
						);
				}
				else {
					throw new PropertyAccessException(
							npe, 
							"NullPointerException occurred while calling", 
							true, 
							clazz, 
							propertyName
						);
				}
			}
			catch (InvocationTargetException ite) {
				throw new PropertyAccessException(
						ite, 
						"Exception occurred inside", 
						true, 
						clazz, 
						propertyName
					);
			}
			catch (IllegalAccessException iae) {
				throw new PropertyAccessException(
						iae, 
						"IllegalAccessException occurred while calling", 
						true, 
						clazz, 
						propertyName
					);
				//cannot occur
			}
			catch (IllegalArgumentException iae) {
				if ( value==null && method.getParameterTypes()[0].isPrimitive() ) {
					throw new PropertyAccessException(
							iae, 
							"Null value was assigned to a property of primitive type", 
							true, 
							clazz, 
							propertyName
						);
				}
				else {
					log.error(
							"IllegalArgumentException in class: " + clazz.getName() +
							", setter method of property: " + propertyName
						);
					log.error(
							"expected type: " + 
							method.getParameterTypes()[0].getName() +
							", actual value: " + 
							( value==null ? null : value.getClass().getName() )
						);
					throw new PropertyAccessException(
							iae, 
							"IllegalArgumentException occurred while calling", 
							true, 
							clazz, 
							propertyName
						);
				}
			}
		}

		public Method getMethod() {
			return method;
		}

		public String getMethodName() {
			return method.getName();
		}

		Object readResolve() {
			return createSetter(clazz, propertyName);
		}

		public String toString() {
			return "BasicSetter(" + clazz.getName() + '.' + propertyName + ')';
		}
	}

	public static final class BasicGetter implements Getter {
		private Class clazz;
		private final transient Method method;
		private final String propertyName;

		private BasicGetter(Class clazz, Method method, String propertyName) {
			this.clazz=clazz;
			this.method=method;
			this.propertyName=propertyName;
		}

		public Object get(Object target) throws HibernateException {
			try {
				return method.invoke(target, null);
			}
			catch (InvocationTargetException ite) {
				throw new PropertyAccessException(
						ite, 
						"Exception occurred inside", 
						false, 
						clazz, 
						propertyName
					);
			}
			catch (IllegalAccessException iae) {
				throw new PropertyAccessException(
						iae, 
						"IllegalAccessException occurred while calling", 
						false, 
						clazz, 
						propertyName
					);
				//cannot occur
			}
			catch (IllegalArgumentException iae) {
				log.error(
						"IllegalArgumentException in class: " + clazz.getName() +
						", getter method of property: " + propertyName
					);
				throw new PropertyAccessException(
						iae, 
						"IllegalArgumentException occurred calling", 
						false, 
						clazz, 
						propertyName
					);
			}
		}

		public Object getForInsert(Object target, Map mergeMap, SessionImplementor session) {
			return get( target );
		}

		public Class getReturnType() {
			return method.getReturnType();
		}

		public Method getMethod() {
			return method;
		}

		public String getMethodName() {
			return method.getName();
		}

		public String toString() {
			return "BasicGetter(" + clazz.getName() + '.' + propertyName + ')';
		}
		
		Object readResolve() {
			return createGetter(clazz, propertyName);
		}
	}


	public Setter getSetter(Class theClass, String propertyName) 
	throws PropertyNotFoundException {
		return createSetter(theClass, propertyName);
	}
	
	private static Setter createSetter(Class theClass, String propertyName) 
	throws PropertyNotFoundException {
		BasicSetter result = getSetterOrNull(theClass, propertyName);
		if (result==null) {
			throw new PropertyNotFoundException( 
					"Could not find a setter for property " + 
					propertyName + 
					" in class " + 
					theClass.getName() 
				);
		}
		return result;
	}

	private static BasicSetter getSetterOrNull(Class theClass, String propertyName) {

		if (theClass==Object.class || theClass==null) return null;

		Method method = setterMethod(theClass, propertyName);

		if (method!=null) {
			if ( !ReflectHelper.isPublic(theClass, method) ) method.setAccessible(true);
			return new BasicSetter(theClass, method, propertyName);
		}
		else {
			BasicSetter setter = getSetterOrNull( theClass.getSuperclass(), propertyName );
			if (setter==null) {
				Class[] interfaces = theClass.getInterfaces();
				for ( int i=0; setter==null && i<interfaces.length; i++ ) {
					setter=getSetterOrNull( interfaces[i], propertyName );
				}
			}
			return setter;
		}

	}

	private static Method setterMethod(Class theClass, String propertyName) {

		BasicGetter getter = getGetterOrNull(theClass, propertyName);
		Class returnType = (getter==null) ? null : getter.getReturnType();

		Method[] methods = theClass.getDeclaredMethods();
		Method potentialSetter = null;
		for (int i=0; i<methods.length; i++) {
			String methodName = methods[i].getName();

			if ( methods[i].getParameterTypes().length==1 && methodName.startsWith("set") ) {
				String testStdMethod = Introspector.decapitalize( methodName.substring(3) );
				String testOldMethod = methodName.substring(3);
				if ( testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName) ) {
					potentialSetter = methods[i];
					if ( returnType==null || methods[i].getParameterTypes()[0].equals(returnType) ) {
						return potentialSetter;
					}
				}
			}
		}
		return potentialSetter;
	}

	public Getter getGetter(Class theClass, String propertyName) 
	throws PropertyNotFoundException {
		return createGetter(theClass, propertyName);
	}
	
	public static Getter createGetter(Class theClass, String propertyName) 
	throws PropertyNotFoundException {
		BasicGetter result = getGetterOrNull(theClass, propertyName);
		if (result==null) {
			throw new PropertyNotFoundException( 
					"Could not find a getter for " + 
					propertyName + 
					" in class " + 
					theClass.getName() 
			);
		}
		return result;

	}

	private static BasicGetter getGetterOrNull(Class theClass, String propertyName) {

		if (theClass==Object.class || theClass==null) return null;

		Method method = getterMethod(theClass, propertyName);

		if (method!=null) {
			if ( !ReflectHelper.isPublic(theClass, method) ) method.setAccessible(true);
			return new BasicGetter(theClass, method, propertyName);
		}
		else {
			BasicGetter getter = getGetterOrNull( theClass.getSuperclass(), propertyName );
			if (getter==null) {
				Class[] interfaces = theClass.getInterfaces();
				for ( int i=0; getter==null && i<interfaces.length; i++ ) {
					getter=getGetterOrNull( interfaces[i], propertyName );
				}
			}
			return getter;
		}
	}

	private static Method getterMethod(Class theClass, String propertyName) {

		Method[] methods = theClass.getDeclaredMethods();
		for (int i=0; i<methods.length; i++) {
			// only carry on if the method has no parameters
			if ( methods[i].getParameterTypes().length == 0 ) {
				String methodName = methods[i].getName();

				// try "get"
				if ( methodName.startsWith("get") ) {
					String testStdMethod = Introspector.decapitalize( methodName.substring(3) );
					String testOldMethod = methodName.substring(3);
					if ( testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName) ) {
						return methods[i];
					}

				}

				// if not "get", then try "is"
				if ( methodName.startsWith("is") ) {
					String testStdMethod = Introspector.decapitalize( methodName.substring(2) );
					String testOldMethod = methodName.substring(2);
					if ( testStdMethod.equals(propertyName) || testOldMethod.equals(propertyName) ) {
						return methods[i];
					}
				}
			}
		}
		return null;
	}

}