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

001:        /*
002:
003:        This software is OSI Certified Open Source Software.
004:        OSI Certified is a certification mark of the Open Source Initiative.
005:
006:        The license (Mozilla version 1.0) can be read at the MMBase site.
007:        See http://www.MMBase.org/license
008:
009:         */
010:        package org.mmbase.storage.search;
011:
012:        /**
013:         * A relationstep refers to a table of relations between the previous and next step. Relationstep are used to create a path of related objects.
014:         * <p>
015:         * This corresponds to a constraint joining the three tables in SQL SELECT-syntax.
016:         * <p>
017:         * Note that tables can also be joined using FieldCompareConstraints.
018:         *
019:         * @author Rob van Maris
020:         * @version $Id: RelationStep.java,v 1.10 2007/12/06 08:13:36 michiel Exp $
021:         * @since MMBase-1.7
022:         */
023:        public interface RelationStep extends Step {
024:
025:            /**
026:             * Directionality following relations both ways (source to destination AND destination to source).
027:             * Whether unidirectional relations are shown is dependent on the value of the checkedDirectionality property.
028:             */
029:            int DIRECTIONS_BOTH = 0;
030:
031:            /**
032:             * Directionality following relations from source to destination.
033:             * E.g. where the previous step is source and the next step is destination.
034:             * Whether unidirectional relations are shown is dependent on the value of the checkedDirectionality property.
035:             */
036:            int DIRECTIONS_DESTINATION = 1;
037:
038:            /**
039:             * Directionality following relations from destination to source.
040:             * E.g. where the previous step is destination and the next step is source.
041:             * This value ignores the value of the checkedDirectionality property.
042:             */
043:            int DIRECTIONS_SOURCE = 2;
044:
045:            /**
046:             * Directionality following relations both ways, including unidirectional relations.
047:             * This value ignores the value of the checkedDirectionality property.
048:             */
049:            int DIRECTIONS_ALL = 4;
050:
051:            /**
052:             * Directionality following relations from destination to source.
053:             * E.g. where the previous step is destination and the next step is source.
054:             * Whether unidirectional relations are shown is dependent on the value of the checkedDirectionality property.
055:             */
056:            int DIRECTIONS_EITHER = 5;
057:
058:            /**
059:             * Directionality names corresponding to the direction values.
060:             * As a result DIRECTIONALITY_DESCRIPTIONS[directionality] is the directionality
061:             * name: "both", "destination", "source", "all" or "either".
062:             */
063:            public final static String[] DIRECTIONALITY_DESCRIPTIONS = new String[] {
064:                    "both", "destination", "source", null, // reserved
065:                    "all", "either" };
066:
067:            /**
068:             * Gets the value of the checkedDirectionality property. This property
069:             * determines how uni/bi-directionality affects which relations are
070:             * followed from destination to source, when the directionality property
071:             * is set to {@link #DIRECTIONS_SOURCE} or {@link #DIRECTIONS_BOTH}.
072:             * <p>
073:             * When this value is true, only bi-directional relations are followed
074:             * from destination to source.
075:             * Otherwise unidirectional relations are followed from destination to
076:             * source as well.
077:             */
078:            boolean getCheckedDirectionality();
079:
080:            /**
081:             * Gets the directionality mode used with this relation. This is one of
082:             * values defined in this class.
083:             */
084:            int getDirectionality();
085:
086:            /**
087:             * Gets the role for this relation, if specified.
088:             * I.e. the nodenumber of the corresponding
089:             * {@link org.mmbase.module.corebuilders.RelDef RelDef} node, or
090:             * <code>null</code>.
091:             */
092:            Integer getRole();
093:
094:            /**
095:             * Gets the previous step.
096:             */
097:            Step getPrevious();
098:
099:            /**
100:             * Gets the next step.
101:             */
102:            Step getNext();
103:
104:            /**
105:             * Compares this relationstep to the specified object. The result is
106:             * <code>true</code> if and only if the argument is a non-null
107:             * RelationStep object with the same directionality and role,
108:             * associated with the same tablename,
109:             * using the same alias and including the same nodes.
110:             *
111:             * @param obj The object to compare with.
112:             * @return <code>true</code> if the objects are equal,
113:             * <code>false</code> otherwise.
114:             * @see Step#equals
115:             */
116:            public boolean equals(Object obj);
117:
118:            // javadoc is inherited
119:            public int hashCode();
120:
121:            /**
122:             * Returns a string representation of this RelationStep.
123:             * The string representation has the form
124:             * "RelationStep(tablename:&lt;tablename&gt;, alias:&lt;alias&gt;,
125:             *  nodes:&lt;nodes&gt;, dir:&lt;dir&gt;, role:&lt;role&gt;)"
126:             * where
127:             * <ul>
128:             * <li><em>&lt;tablename&gt;</em> is the tablename returnedby
129:             *     {@link #getTableName getTableName()}
130:             * <li><em>&lt;alias&gt;</em> is the alias returned by {@link #getAlias getAlias()}
131:             * <li><em>&lt;nodes&gt;</em> is the string representation of the ordered list
132:             *      of nodenumbers returned by {@link #getNodes getNodes()}
133:             * <li><em>&lt;dir&gt;</em> is the name of
134:             *     the directionality returned by
135:             *     {@link #getDirectionality getDirectionality()}
136:             * <li><em>&lt;role&gt;</em> is the role returned by
137:             *     {@link #getRole getRole()}
138:             * </ul>
139:             *
140:             * @return A string representation of this RelationStep.
141:             */
142:            public String toString();
143:
144:        }