/** * * MonadicOperator * Part of Mbase implemented in Java * @author Paul Cockshott Started Aug 1997 Copyright (c) University of strathclyde */ package strathclyde.cs.relational.operators; import strathclyde.cs.relational.*; public abstract class Moperator { public abstract Universal apply(Universal b); public static final Moperator IDENTITY = new Identity(); public static final Moperator LOAD = new LoadRelation(); }
LoadRelation1 is a monadic operator whose syntactic representation in K is the dollar sign and whose signiture is given as follows:
Syntax | Type | Meaning |
$ x | (String® relation) | x is a filename |
containing ',' separated | ||
fields to be loaded as a relation | ||
$ [x,[i,j,...]] | ([String,*int]® relation) | x as above |
i,j,.. key fields | ||
package strathclyde.cs.relational.operators; import java.io.*; import java.util.*; import strathclyde.cs.relational.*; import strathclyde.cs.relational.structured.*; import strathclyde.cs.relational.atomic.*; public class LoadRelation extends Moperator { public Universal apply(Universal b){
If the parameter is a text string interpret this as the name of a comma separated file of text to be loaded with no primary key
} } /*StreamTokenizer tokens= new StreamTokenizer (inputFile); tokens.quoteChar((int)'"'); tokens.eolIsSignificant(true); Vector v=new Vector(); while(tokens.nextToken()!=tokens.TT_EOF){ String line=tokens.sval; if (tokens.nextToken()==tokens.TT_EOL){} else{} v.addElement(line); System.out.println(v);*/
/* * * Doperator *Part of Mbase implemented in Java Author Paul Cockshott Started Aug 1997 Copyright (c) University of strathclyde */ package strathclyde.cs.relational.operators; import strathclyde.cs.relational.*; public abstract class Doperator {}
/** * * Subscript ** Part of Mbase implemented in Java * @author Paul Cockshott Started Sept 1997 Copyright (c) University of strathclyde */ package strathclyde.cs.relational.operators; import strathclyde.cs.relational.*; public class Subscript extends Doperator {}
package strathclyde.cs.relational.operators; import strathclyde.cs.relational.*; import strathclyde.cs.relational.structured.*; /* * * Select * implements the selection operator on sets */ public class Select extends Moperator {}
//package operator; /* * * plus * Part of Mbase implemented in Java Author Paul Cockshott Started Aug 1997 Copyright (c) University of strathclyde */ package strathclyde.cs.relational.operators; import strathclyde.cs.relational.*; public class Plus extends Doperator {}
1 Part of MdBase implemented in Java Author Nikolaos Kotsis Started September 1997 Copyright © University of Strathclyde