page.java

sun公司的petstore,一个J2ee的示例应用程序.

/*
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistribution 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.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * This software is provided "AS IS," without a warranty of any
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN
 * OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR
 * FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR
 * PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF
 * LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *
 * You acknowledge that Software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of
 * any nuclear facility.
 */
package com.sun.j2ee.blueprints.catalog.model;

import java.util.*;
import java.io.Serializable;

/**
 * Represents a page of results (for page-by-page iteration).
 */
public class Page implements Serializable {

  // XXX
  /*
    public static final Page EMPTY_PAGE =
        new Page(Collections.EMPTY_LIST, 0, 0);
        */
    public static final Page EMPTY_PAGE =
        new Page(Collections.EMPTY_LIST, 0, false);

    List objects;
    int start;
  // XXX
  // int containingListSize;
  boolean hasNext;

  // XXX
  /*
    public Page(List l, int s, int cls) {
    */
    public Page(List l, int s, boolean hasNext) {
        objects = new ArrayList(l);
        start = s;
        // XXX
        //containingListSize = cls;
        this.hasNext = hasNext;
    }

    public List getList() { return objects; }

    public boolean isNextPageAvailable() {
      // XXX
      /*
        return (start + objects.size()) < containingListSize;
        */
        return hasNext;
    }

    public boolean isPreviousPageAvailable() {
        return start > 0;
    }

    public int getStartOfNextPage() { return start + objects.size(); }

    public int getStartOfPreviousPage() {
        return Math.max(start-objects.size(), 0);
    }

    public int getSize() { return objects.size(); }
}