001 /*
002 // $Id: //open/mondrian/src/main/mondrian/olap/fun/MultiResolver.java#19 $
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) 2002-2005 Kana Software, Inc. and others
007 // All Rights Reserved.
008 // You must accept the terms of that agreement to use this software.
009 //
010 // jhyde, Feb 12, 2003
011 */
012 package mondrian.olap.fun;
013
014 import mondrian.olap.*;
015
016 /**
017 * A <code>MultiResolver</code> considers several overloadings of the same
018 * function. If one of these overloadings matches the actual arguments, it
019 * calls the factory method {@link #createFunDef}.
020 *
021 * @author jhyde
022 * @since Feb 12, 2003
023 * @version $Id: //open/mondrian/src/main/mondrian/olap/fun/MultiResolver.java#19 $
024 */
025 public abstract class MultiResolver extends FunUtil implements Resolver {
026 private final String name;
027 private final String signature;
028 private final String description;
029 private final String[] signatures;
030 private final Syntax syntax;
031
032 /**
033 * Creates a <code>MultiResolver</code>.
034 *
035 * @param name Name of function or operator
036 * @param signature Signature of function or operator
037 * @param description Description of function or operator
038 * @param signatures Array of possible signatures, each of which is an
039 * encoding of the syntactic type, return type, and parameter
040 * types of this operator. The "Members" operator has a syntactic
041 * type "pxd" which means "an operator with
042 * {@link Syntax#Property property} syntax (p) which returns a set
043 * (x) and takes a dimension (d) as its argument".
044 * See {@link FunUtil#decodeSyntacticType(String)},
045 * {@link FunUtil#decodeReturnCategory(String)},
046 * {@link FunUtil#decodeParameterCategories(String)}.
047 */
048 protected MultiResolver(
049 String name,
050 String signature,
051 String description,
052 String[] signatures) {
053 this.name = name;
054 this.signature = signature;
055 this.description = description;
056 this.signatures = signatures;
057 Util.assertTrue(signatures.length > 0);
058 this.syntax = decodeSyntacticType(signatures[0]);
059 for (int i = 1; i < signatures.length; i++) {
060 Util.assertTrue(decodeSyntacticType(signatures[i]) == syntax);
061 }
062 }
063
064 public String getName() {
065 return name;
066 }
067
068 public String getDescription() {
069 return description;
070 }
071
072 public String getSignature() {
073 return signature;
074 }
075
076 public Syntax getSyntax() {
077 return syntax;
078 }
079
080 public String[] getReservedWords() {
081 return emptyStringArray;
082 }
083
084 public String[] getSignatures() {
085 return signatures;
086 }
087
088 public FunDef getFunDef() {
089 return null;
090 }
091
092 public FunDef resolve(
093 Exp[] args, Validator validator, int[] conversionCount)
094 {
095 outer:
096 for (String signature : signatures) {
097 int[] parameterTypes = decodeParameterCategories(signature);
098 if (parameterTypes.length != args.length) {
099 continue;
100 }
101 for (int i = 0; i < args.length; i++) {
102 if (!validator.canConvert(
103 args[i], parameterTypes[i], conversionCount)) {
104 continue outer;
105 }
106 }
107 int returnType = decodeReturnCategory(signature);
108 FunDef dummy = createDummyFunDef(this, returnType, args);
109 return createFunDef(args, dummy);
110 }
111 return null;
112 }
113
114 public boolean requiresExpression(int k) {
115 for (String signature : signatures) {
116 int[] parameterTypes = decodeParameterCategories(signature);
117 if ((k < parameterTypes.length) &&
118 parameterTypes[k] == Category.Set) {
119 return false;
120 }
121 }
122 return true;
123 }
124
125 protected abstract FunDef createFunDef(Exp[] args, FunDef dummyFunDef);
126 }
127
128 // End MultiResolver.java