Source Code Cross Referenced for Step.java in  » Database-ORM » MMBase » org » mmbase » storage » search » Java Source Code / Java DocumentationJava Source Code and Java Documentation

01:        /*
02:
03:        This software is OSI Certified Open Source Software.
04:        OSI Certified is a certification mark of the Open Source Initiative.
05:
06:        The license (Mozilla version 1.0) can be read at the MMBase site.
07:        See http://www.MMBase.org/license
08:
09:         */
10:        package org.mmbase.storage.search;
11:
12:        import java.util.*;
13:
14:        /**
15:         * A step refers to a table in a search request. Several steps may refer to the same table, therefore each step has an unique alias to identify it.
16:         * <p>
17:         * This corresponds to a table name and alias in SQL SELECT-syntax.
18:         *
19:         * @author Rob van Maris
20:         * @version $Id: Step.java,v 1.5 2007/12/06 08:13:36 michiel Exp $
21:         * @since MMBase-1.7
22:         */
23:        public interface Step {
24:            /**
25:             * Gets the name of the table referred to by this step.
26:             * <p>
27:             * This corresponds to a table name in SQL SELECT-syntax.
28:             */
29:            String getTableName();
30:
31:            /**
32:             * Gets the alias associated with this step.
33:             * <p>
34:             * This corresponds to a table alias in SQL SELECT-syntax.
35:             */
36:            String getAlias();
37:
38:            /**
39:             * Gets nodenumbers for nodes that must be included in this step.
40:             * A null value indicates that no such constraint is applied.
41:             * <p>
42:             * This corresponds to a "number IN (....)" constraint in SQL SELECT syntax.
43:             * <p>
44:             * Note that this can also be achieved by using a FieldValueInConstraint on the "number" field.
45:             */
46:            SortedSet<Integer> getNodes();
47:
48:            /**
49:             * Adds node to nodes.
50:             *
51:             * @param nodeNumber The nodenumber of the node.
52:             * @return This <code>BasicStep</code> instance.
53:             * @throws IllegalArgumentException when an invalid argument is supplied.
54:             */
55:            public Step addNode(int nodeNumber);
56:
57:            /**
58:             * Compares this step to the specified object. The result is
59:             * <code>true</code> if and only if the argument is a non-null
60:             * Step, but not RelationStep, object associated with the same tablename,
61:             * using the same alias and including the same nodes.
62:             *
63:             * @param obj The object to compare with.
64:             * @return <code>true</code> if the objects are equal,
65:             * <code>false</code> otherwise.
66:             * @see RelationStep#equals
67:             */
68:            public boolean equals(Object obj);
69:
70:            // javadoc is inherited
71:            public int hashCode();
72:
73:            /**
74:             * Returns a string representation of this Step.
75:             * The string representation has the form
76:             * "Step(tablename:&lt;tablename&gt;, alias:&lt;alias&gt;, nodes:&lt;nodes&gt;)"
77:             * where
78:             * <ul>
79:             * <li><em>&lt;tablename&gt;</em> is the tablename returnedby
80:             *     {@link #getTableName getTableName()}
81:             * <li><em>&lt;alias&gt;</em> is the alias returned by {@link #getAlias getAlias()}
82:             * <li><em>&lt;nodes&gt;</em> is the string representation of the ordered list
83:             * of nodenumbers returned by {@link #getNodes getNodes()}
84:             * </ul>
85:             *
86:             * @return A string representation of this Step.
87:             */
88:            public String toString();
89:
90:        }