typebindingstrategy.java

JAVA 文章管理系统源码

/*
 * Copyright 2004 The Apache Software Foundation.
 * 
 * Licensed 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.commons.betwixt.strategy;

import java.io.Serializable;
import java.util.Date;

/**
 * Determines the way that a type (of object) should be bound
 * by Betwixt.
 * 
 * @author <a href='http://jakarta.apache.org/commons'>Jakarta Commons Team</a>, <a href='http://www.apache.org'>Apache Software Foundation</a>
 */
public abstract class TypeBindingStrategy {
    
    /**
     * The default Betwixt <code>TypeBindingStrategy</code> implementation.
     * Since the default implementation has no state, 
     * a singleton instance can be provided.
     */
    public static final TypeBindingStrategy DEFAULT = new Default();
    
    /**
     * Gets the binding type to be used for the given Java type.
     * @param type <code>Class</code> for which the binding type is to be determined,
     * not null
     * @return <code>BindingType</code> enumeration indicating the type of binding,
     * not null
     */
    public abstract BindingType bindingType(Class type);
    

    /**
     * Enumerates the possible general ways that Betwixt can map a Java type to an XML type.
     * @author <a href='http://jakarta.apache.org/commons'>Jakarta Commons Team</a>, <a href='http://www.apache.org'>Apache Software Foundation</a>
     */
    public static final class BindingType implements Serializable {
        
        private static final int COMPLEX_INDICATOR = 1;
        private static final int PRIMITIVE_INDICATOR = 2;
        
        /**
         * Indicates that the java type should be bound to a complex xml type.
         * A complex xml type may have child elements and attributes.
         * Betwixt determines the mapping for a java bean bound to a complex type.  
         */
        public static final BindingType COMPLEX = new BindingType(COMPLEX_INDICATOR);
        
        /**
         * Indicates that the type should be bound as a Java primitive.
         * Betwixt may bind this to an attribute or a simple xml type.
         * Which is determined by the configuration for binding primitives.
         */
        public static final BindingType PRIMITIVE = new BindingType(PRIMITIVE_INDICATOR);
        
        private int type;
        
        private BindingType(int type) {
            this.type = type;
        }
        
        
        /**
         * @see java.lang.Object#equals(java.lang.Object)
         */
        public boolean equals(Object object) {
            boolean result = false;
            if (object instanceof BindingType) {
                BindingType bindingType = (BindingType) object;
                result = (type == bindingType.type);
            }
            return result;
        }
        
        /**
         * @see java.lang.Object#hashCode()
         */
        public int hashCode() {
            return type;
        }
        
        /**
         * @see java.lang.Object#toString()
         */
        public String toString() {
            StringBuffer buffer = new StringBuffer();
            buffer.append("BindingType: ");
            switch (type) {
      			case (COMPLEX_INDICATOR):
      		    		buffer.append("COMPLEX");
    		    			break;
            
            		case (PRIMITIVE_INDICATOR):
            		    buffer.append("PRIMITIVE");
            		    break;
            }
            
            return buffer.toString();
        }
}
    
    /**
     * The default <code>TypeBindingStrategy</code> used by Betwixt.
     * This implementation recognizes all the usual Java primitive wrappers 
     * (plus a few more that will in most typical use cases be regarded in the same way). 
     * @author <a href='http://jakarta.apache.org/commons'>Jakarta Commons Team</a>, <a href='http://www.apache.org'>Apache Software Foundation</a>
     */
    public static final class Default extends TypeBindingStrategy {

        /**
         * Gets the binding type to be used for the given Java type.
         * This implementation recognizes all the usual Java primitive wrappers 
         * (plus a few more that will in most typical use cases be regarded in the same way). 
         * @param type <code>Class</code> for which the binding type is to be determined,
         * not null
         * @return <code>BindingType</code> enumeration indicating the type of binding,
         * not null
         */
        public BindingType bindingType(Class type) {
            BindingType result =  BindingType.COMPLEX;
            if (isStandardPrimitive(type)) {
                result = BindingType.PRIMITIVE;
            }
       
            return result;
        }
        
        /**
         * is the given type one of the standard Betwixt primitives?
         * @param type <code>Class</code>, not null
         * @return true if the type is one of the standard Betwixt primitives
         */
        protected boolean isStandardPrimitive(Class type) {
            if ( type == null ) {
                return false;
                
            } else if ( type.isPrimitive() ) {
                return true;
                
            } else if ( type.equals( Object.class ) ) {
                return false;
            }
            return type.getName().startsWith( "java.lang." )
                || Number.class.isAssignableFrom( type ) 
                || String.class.isAssignableFrom( type ) 
                || Date.class.isAssignableFrom( type ) 
                || java.sql.Date.class.isAssignableFrom( type ) 
                || java.sql.Time.class.isAssignableFrom( type ) 
                || java.sql.Timestamp.class.isAssignableFrom( type ) 
                || java.math.BigDecimal.class.isAssignableFrom( type ) 
                || java.math.BigInteger.class.isAssignableFrom( type );
        }
    }
}