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Struts example source code file (RequestMap.java)

This example Struts source code file (RequestMap.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 - Struts tags/keywords

abstractmap, entry, entry, enumeration, enumeration, hashset, http, httpservletrequest, io, object, object, request, requestmap, response, serializable, servlet, set, string, string, util

The Struts RequestMap.java source code

/*
 * $Id: RequestMap.java 911398 2010-02-18 13:45:08Z lukaszlenart $
 *
 * 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.struts2.dispatcher;

import javax.servlet.http.HttpServletRequest;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;


/**
 * A simple implementation of the {@link java.util.Map} interface to handle a collection of request attributes.
 */
public class RequestMap extends AbstractMap implements Serializable {

    private static final long serialVersionUID = -7675640869293787926L;

    private Set<Object> entries;
    private HttpServletRequest request;


    /**
     * Saves the request to use as the backing for getting and setting values
     *
     * @param request the http servlet request.
     */
    public RequestMap(final HttpServletRequest request) {
        this.request = request;
    }


    /**
     * Removes all attributes from the request as well as clears entries in this map.
     */
    public void clear() {
        entries = null;
        Enumeration keys = request.getAttributeNames();

        while (keys.hasMoreElements()) {
            String key = (String) keys.nextElement();
            request.removeAttribute(key);
        }
    }

    /**
     * Returns a Set of attributes from the http request.
     *
     * @return a Set of attributes from the http request.
     */
    public Set entrySet() {
        if (entries == null) {
            entries = new HashSet<Object>();

            Enumeration enumeration = request.getAttributeNames();

            while (enumeration.hasMoreElements()) {
                final String key = enumeration.nextElement().toString();
                final Object value = request.getAttribute(key);
                entries.add(new Entry() {
                    public boolean equals(Object obj) {
                        if (!(obj instanceof Entry)) {
                            return false;
                        }
                        Entry entry = (Entry) obj;

                        return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
                    }

                    public int hashCode() {
                        return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
                    }

                    public Object getKey() {
                        return key;
                    }

                    public Object getValue() {
                        return value;
                    }

                    public Object setValue(Object obj) {
                        request.setAttribute(key, obj);

                        return value;
                    }
                });
            }
        }

        return entries;
    }

    /**
     * Returns the request attribute associated with the given key or <tt>null if it doesn't exist.
     *
     * @param key the name of the request attribute.
     * @return the request attribute or <tt>null if it doesn't exist.
     */
    public Object get(Object key) {
        return request.getAttribute(key.toString());
    }

    /**
     * Saves an attribute in the request.
     *
     * @param key   the name of the request attribute.
     * @param value the value to set.
     * @return the object that was just set.
     */
    public Object put(Object key, Object value) {
        Object oldValue = get(key);
        entries = null;
        request.setAttribute(key.toString(), value);
        return oldValue;
    }

    /**
     * Removes the specified request attribute.
     *
     * @param key the name of the attribute to remove.
     * @return the value that was removed or <tt>null if the value was not found (and hence, not removed).
     */
    public Object remove(Object key) {
        entries = null;

        Object value = get(key);
        request.removeAttribute(key.toString());

        return value;
    }
}

Other Struts examples (source code examples)

Here is a short list of links related to this Struts RequestMap.java source code file:

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