Source code: org/apache/ojb/broker/query/Query.java
1 package org.apache.ojb.broker.query;
2
3 /* ====================================================================
4 * The Apache Software License, Version 1.1
5 *
6 * Copyright (c) 2001 The Apache Software Foundation. All rights
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14 * notice, this list of conditions and the following disclaimer.
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22 * if any, must include the following acknowledgment:
23 * "This product includes software developed by the
24 * Apache Software Foundation (http://www.apache.org/)."
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29 * "Apache ObjectRelationalBridge" must not be used to endorse or promote products
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50 *
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55 */
56
57 /**
58 * represents Queries that can be used by the OJB PersistenceBroker
59 * to retrieve Objects from the underlying DB.
60 * Until now there are two implementations:
61 * 1. QueryByCriteria, represents SELECT * FROM ... WHERE ... queries
62 * 2. QueryByIdentity, uses Example objects or OIDs
63 * as templates for the db lookup
64 * there could additional implementations, e.g for user defined SQL
65 *
66 * For the Criteria API I reused code from the COBRA project,
67 * as you will see by their class comments.
68 *
69 * I removed all stuff that relies on knowlegde of the DataDictionary
70 * or MetaData layer. The Query and Criteria classes thus don't know
71 * how to build SQL statements, as in the COBRA original sources.
72 * I use the this classes as mere data-structures, that are
73 * processed by the OJB Accesslayer (SqlGenerator, JdbcAccess).
74 *
75 * This design will allow to reuse the org.apache.ojb.broker.query package in other
76 * projects without breaking any references. I hope this will be
77 * useful for someone.
78 *
79 * @author Thomas Mahler
80 */
81 public interface Query extends java.io.Serializable
82 {
83 public static final int NO_START_AT_INDEX = 0;
84 public static final int NO_END_AT_INDEX = 0;
85 public static final boolean SCROLLABLE = true;
86 public static final boolean NOT_SCROLLABLE = false;
87
88 /**
89 * return the criteria of the query if present or null.
90 */
91 public abstract Criteria getCriteria();
92
93 /**
94 * return the template Object if present or null
95 */
96 public abstract Object getExampleObject();
97
98 /**
99 * return the target class, representing the extend to be searched
100 */
101 public abstract Class getSearchClass();
102
103 /**
104 * return true if select DISTINCT should be used
105 */
106 public boolean isDistinct();
107
108 /**
109 *
110 * @return the row at which the query should start retrieving results. If the start at index is -1, then ignore all
111 * cursor control.
112 */
113 int getStartAtIndex();
114
115 /**
116 * Set the row at which the query should start retrieving results, inclusive.
117 * @param startAtIndex starting index, inclusive.
118 */
119 void setStartAtIndex(int startAtIndex);
120
121 /**
122 *
123 * @return the row at which the query should stop retrieving results. If the end at index is -1, ignore all cursor
124 * control
125 */
126 int getEndAtIndex();
127
128 /**
129 * Set the row at which the query should stop retieving results, exlusive.
130 * @param endAtIndex ending index, exclusive
131 */
132 void setEndAtIndex(int endAtIndex);
133
134 void fullSize(int size);
135 int fullSize();
136
137 }