collectionstringextractor.java

来自「resetful样式的ws样例,一种面向资源的webservices服务」· Java 代码 · 共 125 行

/*
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://jersey.dev.java.net/CDDL+GPL.html
 * or jersey/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at jersey/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 * 
 * Contributor(s):
 * 
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package com.sun.jersey.impl.model.parameter.multivalued;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import javax.ws.rs.core.MultivaluedMap;

/**
 *
 * @author [e-mail]
 */
abstract class CollectionStringExtractor<V extends Collection<String>> 
        implements MultivaluedParameterExtractor {
    final String parameter;
    final String defaultValue;

    protected CollectionStringExtractor(String parameter, String defaultValue) {
        this.parameter = parameter;
        this.defaultValue = defaultValue;
    }

    public Object extract(MultivaluedMap<String, String> parameters) {
        List<String> stringList = parameters.get(parameter);
        if (stringList != null) {
            V copy = getInstance();
            copy.addAll(stringList);
            return copy;
        } else if (defaultValue != null) {
            V l = getInstance();
            l.add(defaultValue);
            return l;
        }

        return null;
    }
    
    protected abstract V getInstance();
    
    private static final class ListString extends CollectionStringExtractor<List<String>> {
        public ListString(String parameter, String defaultValue) {
            super(parameter, defaultValue);
        }

        @Override
        protected List<String> getInstance() {
            return new ArrayList<String>();
        }   
    }
    
    private static final class SetString extends CollectionStringExtractor<Set<String>> {
        public SetString(String parameter, String defaultValue) {
            super(parameter, defaultValue);
        }

        @Override
        protected Set<String> getInstance() {
            return new HashSet<String>();
        }   
    }
    
    private static final class SortedSetString extends CollectionStringExtractor<SortedSet<String>> {
        public SortedSetString(String parameter, String defaultValue) {
            super(parameter, defaultValue);
        }

        @Override
        protected SortedSet<String> getInstance() {
            return new TreeSet<String>();
        }   
    }
    
    static MultivaluedParameterExtractor getInstance(Class c, 
            String parameter, String defaultValue) {
        if (List.class == c)
            return new ListString(parameter, defaultValue);
        else if (Set.class == c)
            return new SetString(parameter, defaultValue);
        else if (SortedSet.class == c)
            return new SortedSetString(parameter, defaultValue);
        else
            throw new RuntimeException();
    }
}