query.java

这是学习Java必须读懂两套源代码

/**
 * Copyright (C) 2001 Yasna.com. All rights reserved.
 *
 * ===================================================================
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by
 *        Yasna.com (http://www.yasna.com)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Yazd" and "Yasna.com" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please
 *    contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Yazd",
 *    nor may "Yazd" appear in their name, without prior written
 *    permission of Yasna.com.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL YASNA.COM OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Yasna.com. For more information
 * on Yasna.com, please see <http://www.yasna.com>.
 */

/**
 * Copyright (C) 2000 CoolServlets.com. All rights reserved.
 *
 * ===================================================================
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by
 *        CoolServlets.com (http://www.coolservlets.com)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Jive" and "CoolServlets.com" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please
 *    contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Jive",
 *    nor may "Jive" appear in their name, without prior written
 *    permission of CoolServlets.com.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL COOLSERVLETS.COM OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of CoolServlets.com. For more information
 * on CoolServlets.com, please see <http://www.coolservlets.com>.
 */

package com.Yasna.forum;

import java.util.Date;
import java.util.Iterator;

/**
 * Encapsulates a search for content in a forum. Use the factory method
 * forum.createQuery() to get a handle on a Query object. From there, set
 * the properties that you're interested in searching on. For example, to
 * search a forum for "Jive is cool", you would use the following code:<p>
 *
 * <pre>
 * Query query = forum.createQuery();
 * query.setQueryString("Jive is cool");
 * Iterator iter = query.results();
 * while (iter.hasNext()) {
 *     ForumMessage message = (ForumMessage)iter.nextElement();
 *     //print results...
 * }
 * </pre><p>
 *
 * All search properties are optional. You can mix and match them depending on
 * what kind of query you'd like to perform.<p>
 *
 * You can also use the filter methods to restrict searches to messages
 * from a particular user, messages between a date range, or messages in a
 * particular thread.
 */
public interface Query {

    /**
     * Returns the query string for the Query object. The query string is a
     * set of keywords that should be searched on. Currently only "and" keyword
     * searches are supported -- that is, only results that contain every
     * keyword will be returned. In general, keywords should be seperated by
     * spaces. However, other delimiter characters are legal and will be
     * ignored.
     * <p>
     * If the query string has not been set, this method will return null.
     *
     * @return the Query query string.
     */
    public String getQueryString();

    /**
     * Sets the query string for the Query object. The query string is a
     * set of keywords that should be searched on. Currently only "and" keyword
     * searches are supported -- that is, only results that contain every
     * keyword will be returned. In general, keywords should be seperated by
     * spaces. However, other delimiter characters are legal and will be
     * ignored.
     *
     * @param queryString a new query string.
     */
    public void setQueryString(String queryString);

    /**
     * Returns the latest date for search results. For example, the "before date"
     * can be used to search for messages modified more than 1 month ago.
     * <p>
     * If the "before date" has not been set, this method will return null.
     *
     * @return the upder date boundary for search results.
     */
    public Date getBeforeDate();

    /**
     * Sets the latest date for search results. For example, the "before date"
     * can be used to search for messages modified more than 1 month ago.
     *
     * @param beforeDate an upper date boundary for search results.
     */
    public void setBeforeDate(Date beforeDate);

    /**
     * Returns the earliest date for search results. For example, the "after date"
     * can be used to search for messages modified within the last week.<p>
     *
     * If the "after date" has not been set, this method will return null.
     *
     * @return the lower date boundary for search results.
     */
    public Date getAfterDate();

    /**
     * Sets the earliest date for search results. For example, the "after date"
     * can be used to search for messages modified within the last week.
     *
     * @param afterDate a lower date boundary for search results.
     */
    public void setAfterDate(Date afterDate);

    /**
     * Returns the user that query results are restricted to. If the query
     * is not restricted to messages posted by a certain user, this method will
     * return null.
     *
     * @return the message that results are restricted to.
     */
    public User getFilteredUser();

    /**
     * Restricts the query results to messages posted by a specified user.
     *
     * @param user a User to restrict query results to.
     */
    public void filterOnUser(User user);

    /**
     * Returns the thread that query results are restricted to. If the query
     * is not restricted to messages in a certain thread, this method will
     * return null.
     *
     * @return the thread that results are restricted to.
     */
    public ForumThread getFilteredThread();

    /**
     * Restricts the querty results to messages posted in a specified thread.
     *
     * @param thread the ForumThread to restrict query results to.
     */
    public void filterOnThread(ForumThread thread);

    /**
     * Returns the total number of results of the query.
     *
     * @return the number of results of the query.
     */
    public int resultCount();

    /**
     * Returns the results of the Query as an Iterator of ForumMessage objects.
     *
     * @return the result of the query as an Iterator.
     */
    public Iterator results();

    /**
     * Returns the results of the Query as an Iterator of ForumMessage objects.
     * The startIndex and numResults paramaters are used to look at a certain
     * range of the results. For example, the first twenty results, the second
     * twenty results, etc. This is useful for user interface with multiple
     * pages of results.<p>
     *
     * If startIndex or numResults does not fall within the range of results,
     * the number of messages returned may be smaller than expected. For
     * example, suppose a query has a total of 17 results. If startIndex
     * is 0 and numResults is 25, only 17 results can be returned.
     *
     * @param startIndex the index in the results that the iterator will start at.
     * @param numResuls the max number of results that should be returned.
     * @return the result of the query as an Iterator.
     */
    public Iterator results(int startIndex, int numResults);
}