propertyeditorfactory.java

mina是以Java实现的一个开源的网络程序框架

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.apache.mina.integration.beans;

import java.beans.PropertyEditor;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

/**
 * A factory that creates a new {@link PropertyEditor} which is appropriate for
 * the specified object or class. 
 * 
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev: 601247 $, $Date: 2007-12-05 09:42:41 +0100 (Wed, 05 Dec 2007) $
 */
public final class PropertyEditorFactory {
    @SuppressWarnings("unchecked")
    public static PropertyEditor getInstance(Object object) {
        if (object == null) {
            return new NullEditor();
        }
        
        if (object instanceof Collection) {
            Class<?> elementType = null;
            for (Object e: (Collection) object) {
                if (e != null) {
                    elementType = e.getClass();
                    break;
                }
            }
            
            if (elementType != null) {
                if (object instanceof Set) {
                    return new SetEditor(elementType);
                }
                
                if (object instanceof List) {
                    return new ListEditor(elementType);
                }
                
                return new CollectionEditor(elementType);
            }
        }
        
        if (object instanceof Map) {
            Class<?> keyType = null;
            Class<?> valueType = null;
            for (Object entry: ((Map) object).entrySet()) {
                Map.Entry e = (Map.Entry) entry;
                if (e.getKey() != null && e.getValue() != null) {
                    keyType = e.getKey().getClass();
                    valueType = e.getValue().getClass();
                    break;
                }
            }
            
            if (keyType != null && valueType != null) {
                return new MapEditor(keyType, valueType);
            }
        }
        
        return getInstance(object.getClass());
    }
    
    // parent type / property name / property type
    public static PropertyEditor getInstance(Class<?> type) {
        if (type == null) {
            throw new NullPointerException("type");
        }
        
        if (type.isEnum()) {
            return new EnumEditor(type);
        }
        
        if (type.isArray()) {
            return new ArrayEditor(type.getComponentType());
        }
        
        if (Collection.class.isAssignableFrom(type)) {
            if (Set.class.isAssignableFrom(type)) {
                return new SetEditor(String.class);
            }
            
            if (List.class.isAssignableFrom(type)) {
                return new ListEditor(String.class);
            }
            
            return new CollectionEditor(String.class);
        }
        
        if (Map.class.isAssignableFrom(type)) {
            return new MapEditor(String.class, String.class);
        }
        
        if (Properties.class.isAssignableFrom(type)) {
            return new PropertiesEditor();
        }
        
        type = filterPrimitiveType(type);

        try {
            return (PropertyEditor)
                    PropertyEditorFactory.class.getClassLoader().loadClass(
                            PropertyEditorFactory.class.getPackage().getName() +
                            '.' + type.getSimpleName() + "Editor").newInstance();
        } catch (Exception e) {
            return null;
        }
    }
    
    private static Class<?> filterPrimitiveType(Class<?> type) {
        if (type.isPrimitive()) {
            if (type == boolean.class) {
                type = Boolean.class;
            }
            if (type == byte.class) {
                type = Byte.class;
            }
            if (type == char.class) {
                type = Character.class;
            }
            if (type == double.class) {
                type = Double.class;
            }
            if (type == float.class) {
                type = Float.class;
            }
            if (type == int.class) {
                type = Integer.class;
            }
            if (type == long.class) {
                type = Long.class;
            }
            if (type == short.class) {
                type = Short.class;
            }
        }
        return type;
    }
    
    private PropertyEditorFactory() {
    }
}