GenericSelectQuery


1   /* ====================================================================
2    * 
3    * The ObjectStyle Group Software License, version 1.1
4    * ObjectStyle Group - http://objectstyle.org/
5    * 
6    * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
7    * of the software. All rights reserved.
8    * 
9    * Redistribution and use in source and binary forms, with or without
10   * modification, are permitted provided that the following conditions
11   * are met:
12   * 
13   * 1. Redistributions of source code must retain the above copyright
14   *    notice, this list of conditions and the following disclaimer.
15   * 
16   * 2. Redistributions in binary form must reproduce the above copyright
17   *    notice, this list of conditions and the following disclaimer in
18   *    the documentation and/or other materials provided with the
19   *    distribution.
20   * 
21   * 3. The end-user documentation included with the redistribution, if any,
22   *    must include the following acknowlegement:
23   *    "This product includes software developed by independent contributors
24   *    and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
25   *    Alternately, this acknowlegement may appear in the software itself,
26   *    if and wherever such third-party acknowlegements normally appear.
27   * 
28   * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
29   *    or promote products derived from this software without prior written
30   *    permission. For written permission, email
31   *    "andrus at objectstyle dot org".
32   * 
33   * 5. Products derived from this software may not be called "ObjectStyle"
34   *    or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
35   *    names without prior written permission.
36   * 
37   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40   * DISCLAIMED.  IN NO EVENT SHALL THE OBJECTSTYLE GROUP OR
41   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48   * SUCH DAMAGE.
49   * ====================================================================
50   * 
51   * This software consists of voluntary contributions made by many
52   * individuals and hosted on ObjectStyle Group web site.  For more
53   * information on the ObjectStyle Group, please see
54   * <http://objectstyle.org/>.
55   */
56  package org.objectstyle.cayenne.query;
57  
58  import java.util.Collection  ;
59  
60  /**
61   * A query that returns result set. Concrete implementations can be object queries, raw
62   * sql queries, stored procedure queries, etc. The most commonly used GenericSelectQueries
63   * are {@link SelectQuery},{@link SQLTemplate}and {@link ProcedureQuery}.
64   * 
65   * @author Andrei Adamchik
66   */
67  public interface GenericSelectQuery extends Query {
68  
69      /**
70       * A cache policy that disables caching of query results.
71       * 
72       * @since 1.1
73       */
74      public static final String   NO_CACHE = "nocache";
75  
76      /**
77       * A cache policy ruling that query results shall be cached separately for each
78       * DataContext.
79       * 
80       * @since 1.1
81       */
82      public static final String   LOCAL_CACHE = "localcache";
83  
84      /**
85       * A cache policy ruling that query results shall be stored in a shared cache
86       * accessible by all DataContexts.
87       * 
88       * @since 1.1
89       */
90      public static final String   SHARED_CACHE = "sharedcache";
91  
92      /**
93       * Defines the name of the property for the query {@link #getFetchLimit() fetch limit}.
94       * 
95       * @since 1.1
96       */
97      public static final String   FETCH_LIMIT_PROPERTY = "cayenne.GenericSelectQuery.fetchLimit";
98  
99      /**
100      * Defines default query fetch limit, which is zero, meaning that all matching rows
101      * should be fetched.
102      * 
103      * @since 1.1
104      */
105     public static final int FETCH_LIMIT_DEFAULT = 0;
106 
107     /**
108      * Defines the name of the property for the query {@link #getPageSize() page size}.
109      * 
110      * @since 1.1
111      */
112     public static final String   PAGE_SIZE_PROPERTY = "cayenne.GenericSelectQuery.pageSize";
113 
114     /**
115      * Defines default query page size, which is zero for no pagination.
116      * 
117      * @since 1.1
118      */
119     public static final int PAGE_SIZE_DEFAULT = 0;
120 
121     /**
122      * @since 1.1
123      */
124     public static final String   FETCHING_DATA_ROWS_PROPERTY = "cayenne.GenericSelectQuery.fetchingDataRows";
125 
126     /**
127      * @since 1.1
128      */
129     public static final boolean FETCHING_DATA_ROWS_DEFAULT = false;
130 
131     /**
132      * @since 1.1
133      */
134     public static final String   REFRESHING_OBJECTS_PROPERTY = "cayenne.GenericSelectQuery.refreshingObjects";
135 
136     /**
137      * @since 1.1
138      */
139     public static final boolean REFRESHING_OBJECTS_DEFAULT = true;
140 
141     /**
142      * @since 1.1
143      */
144     public static final String   RESOLVING_INHERITED_PROPERTY = "cayenne.GenericSelectQuery.resolvingInherited";
145 
146     /**
147      * @since 1.1
148      */
149     public static final boolean RESOLVING_INHERITED_DEFAULT = true;
150 
151     /**
152      * @since 1.1
153      */
154     public static final String   CACHE_POLICY_PROPERTY = "cayenne.GenericSelectQuery.cachePolicy";
155 
156     /**
157      * @since 1.1
158      */
159     public static final String   CACHE_POLICY_DEFAULT = NO_CACHE;
160 
161     /**
162      * Returns query cache policy, which can be one of {@link #NO_CACHE},
163      * {@link #LOCAL_CACHE}, or {@link #SHARED_CACHE}. NO_CACHE is generally a default
164      * policy.
165      * 
166      * @since 1.1
167      */
168     public String   getCachePolicy();
169 
170     /**
171      * Returns <code>true</code> if this query should produce a list of data rows as
172      * opposed to DataObjects, <code>false</code> for DataObjects. This is a hint to
173      * QueryEngine executing this query.
174      */
175     public boolean isFetchingDataRows();
176 
177     /**
178      * Returns <code>true</code> if the query results should replace any currently
179      * cached values, returns <code>false</code> otherwise. If
180      * {@link #isFetchingDataRows()}returns <code>true</code>, this setting is not
181      * applicable and has no effect.
182      * 
183      * @since 1.1
184      */
185     public boolean isRefreshingObjects();
186 
187     /**
188      * Returns true if objects fetched via this query should be fully resolved according
189      * to the inheritance hierarchy.
190      * 
191      * @since 1.1
192      */
193     public boolean isResolvingInherited();
194 
195     /**
196      * Returns query page size. Page size is a hint to Cayenne that query should be
197      * performed page by page, instead of retrieveing all results at once. If the value
198      * returned is less than or equal to zero, no paging should occur.
199      */
200     public int getPageSize();
201 
202     /**
203      * Returns the limit on the maximium number of records that can be returned by this
204      * query. If the actual number of rows in the result exceeds the fetch limit, they
205      * will be discarded. One possible use of fetch limit is using it as a safeguard
206      * against large result sets that may lead to the application running out of memory,
207      * etc. If a fetch limit is greater or equal to zero, all rows will be returned.
208      * 
209      * @return the limit on the maximium number of records that can be returned by this
210      *         query
211      */
212     public int getFetchLimit();
213     
214     /**
215      * Returns a collection of joint prefetches. Joint prefetches (unlike regular ones)
216      * are possible in all types of selecting queries.
217      * 
218      * @since 1.2
219      */
220     public Collection   getJointPrefetches();
221 }
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags