/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.sdb.layout2.expr;
import org.apache.jena.sdb.SDBException ;
import org.apache.jena.sdb.compiler.ConditionCompiler ;
import org.apache.jena.sdb.compiler.SDBConstraint ;
import org.apache.jena.sdb.core.ExprPattern ;
import org.apache.jena.sdb.core.Scope ;
import org.apache.jena.sdb.core.sqlexpr.* ;
import org.apache.jena.sdb.exprmatch.ActionMatch ;
import org.apache.jena.sdb.exprmatch.ActionMatchString ;
import org.apache.jena.sdb.exprmatch.ActionMatchVar ;
import org.apache.jena.sdb.exprmatch.MapResult ;
import org.apache.jena.sdb.layout2.ValueType ;
import org.apache.jena.sparql.core.Var ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.expr.Expr ;
import org.slf4j.LoggerFactory;
public class StringExprCompiler implements ConditionCompiler
{
private static ExprPattern equalsString1 = new ExprPattern("?a1 = ?a2",
new Var[]{ Var.alloc("a1") , Var.alloc("a2") },
new ActionMatch[]{ new ActionMatchVar() ,
new ActionMatchString()}) ;
// As equalsString1 but reverse the arguments.
private static ExprPattern equalsString2 = new ExprPattern("?a2 = ?a1",
new Var[]{ Var.alloc("a1") , Var.alloc("a2") },
new ActionMatch[]{ new ActionMatchVar() ,
new ActionMatchString()}) ;
// private static ExprPattern equalsString3 = new ExprPattern("str(?a1) = ?a2",
// new Var[]{ Var.alloc("a1") , Var.alloc("a2") },
// new Action[]{ new ActionMatchVar() ,
// new ActionMatchString()}) ;
//// As equalsString3 but reverse the arguments.
// private static ExprPattern equalsString4 = new ExprPattern("?a1 = str(?a2)",
// new Var[]{ Var.alloc("a1") , Var.alloc("a2") },
// new Action[]{ new ActionMatchString() ,
// new ActionMatchVar() }) ;
@Override
public SDBConstraint recognize(Expr expr)
{
MapResult rMap = null ;
if ( ( rMap = equalsString1.match(expr) ) != null )
{
Var var = rMap.get("a1").getExprVar().asVar() ;
String str = rMap.get("a2").getConstant().getString() ;
return new StringEqualsSqlGen(expr, equalsString1, true) ;
}
return null ;
}
}
class StringEqualsSqlGen extends SDBConstraint
{
ExprPattern exprPattern ;
boolean completeConstraint ;
public StringEqualsSqlGen(Expr expr, ExprPattern exprPattern, boolean completeConstraint)
{
super(expr, completeConstraint) ;
this.exprPattern = exprPattern ;
}
@Override
public SDBConstraint substitute(Binding binding)
{
return new StringEqualsSqlGen(getExpr().copySubstitute(binding),
exprPattern,
super.isComplete()) ;
}
@Override
public SqlExpr compile(Scope scope)
{
MapResult rMap = exprPattern.match(getExpr()) ;
if ( rMap == null )
throw new SDBException("Couldn't compile after all: "+getExpr()) ;
//log.info("equalsString - Matched: ?a1 = "+rMap.get("a1")+" : ?a2 = "+rMap.get("a2")) ;
Var var = rMap.get("a1").getExprVar().asVar() ;
String str = rMap.get("a2").getConstant().getString() ;
if ( ! scope.hasColumnForVar(var) )
{
LoggerFactory.getLogger(this.getClass()).error("Variable '"+var+"' not in scope") ;
return null ;
}
SqlColumn vCol = scope.findScopeForVar(var).getColumn() ;
SqlColumn lexCol = new SqlColumn(vCol.getTable(), "lex") ;
SqlColumn vTypeCol = new SqlColumn(vCol.getTable(), "type") ;
// "is a string"
SqlExpr isStr = new S_Equal(vTypeCol, new SqlConstant(ValueType.STRING.getTypeId())) ;
isStr.addNote("is a string" ) ;
// Equality
SqlExpr strEquals = new S_Equal(lexCol, new SqlConstant(str)) ;
isStr.addNote(getExpr().toString()) ;
return new S_And(isStr, strEquals) ;
}
// // --- starts-with
// private static ExprPattern startsWith1 = new ExprPattern("fn:starts-with(?a1, ?a2)",
// new String[]{ "a1" , "a2" },
// new Action[]{ new ActionMatchVar() ,
// new ActionMatchString()}) ;
//
// private static ExprPattern startsWith2 = new ExprPattern("fn:starts-with(str(?a1), ?a2)",
// new String[]{ "a1" , "a2" },
// new Action[]{ new ActionMatchVar() ,
// new ActionMatchString()}) ;
}