001    /*
002    // $Id: //open/mondrian-release/3.0/src/main/mondrian/olap/type/SetType.java#2 $
003    // This software is subject to the terms of the Common Public License
004    // Agreement, available at the following URL:
005    // http://www.opensource.org/licenses/cpl.html.
006    // Copyright (C) 2005-2008 Julian Hyde
007    // All Rights Reserved.
008    // You must accept the terms of that agreement to use this software.
009    */
010    package mondrian.olap.type;
011    
012    import mondrian.olap.*;
013    
014    /**
015     * Set type.
016     *
017     * @author jhyde
018     * @since Feb 17, 2005
019     * @version $Id: //open/mondrian-release/3.0/src/main/mondrian/olap/type/SetType.java#2 $
020     */
021    public class SetType implements Type {
022    
023        private final Type elementType;
024        private final String digest;
025    
026        /**
027         * Creates a type representing a set of elements of a given type.
028         *
029         * @param elementType The type of the elements in the set, or null if not
030         *   known
031         */
032        public SetType(Type elementType) {
033            if (elementType != null) {
034                assert elementType instanceof MemberType ||
035                        elementType instanceof TupleType;
036            }
037            this.elementType = elementType;
038            this.digest = "SetType<" + elementType + ">";
039        }
040    
041        public int hashCode() {
042            return digest.hashCode();
043        }
044    
045        public boolean equals(Object obj) {
046            if (obj instanceof SetType) {
047                SetType that = (SetType) obj;
048                return Util.equals(this.elementType, that.elementType);
049            } else {
050                return false;
051            }
052        }
053    
054        public String toString() {
055            return digest;
056        }
057    
058        /**
059         * Returns the type of the elements of this set.
060         *
061         * @return the type of the elements in this set
062         */
063        public Type getElementType() {
064            return elementType;
065        }
066    
067        public boolean usesDimension(Dimension dimension, boolean definitely) {
068            if (elementType == null) {
069                return definitely;
070            }
071            return elementType.usesDimension(dimension, definitely);
072        }
073    
074        public Dimension getDimension() {
075            return elementType == null ? null :
076                    elementType.getDimension();
077        }
078    
079        public Hierarchy getHierarchy() {
080            return elementType == null ? null :
081                    elementType.getHierarchy();
082        }
083    
084        public Level getLevel() {
085            return elementType == null ? null :
086                    elementType.getLevel();
087        }
088    
089        /**
090         * Returns the dimensionality of this SetType. If set contains members,
091         * returns 1, otherwise returns the width of the tuples.
092         *
093         * @return Dimensionality of this SetType
094         */
095        public int getArity() {
096            return elementType instanceof TupleType ?
097                ((TupleType) elementType).elementTypes.length :
098                1;
099        }
100    
101        public Type computeCommonType(Type type, int[] conversionCount) {
102            if (!(type instanceof SetType)) {
103                return null;
104            }
105            SetType that = (SetType) type;
106            final Type mostGeneralElementType =
107                this.getElementType().computeCommonType(
108                    that.getElementType(), conversionCount);
109            if (mostGeneralElementType == null) {
110                return null;
111            }
112            return new SetType(mostGeneralElementType);
113        }
114    }
115    
116    // End SetType.java