GH-2924: Lateral - fixed injection for tables, enhanced QueryExec API…

… for easier testing.

jena-arq/src/main/java/org/apache/jena/query/Query.java

@@ -27,7 +27,7 @@
 import org.apache.jena.atlas.logging.Log ;
 import org.apache.jena.graph.Node ;
 import org.apache.jena.sparql.ARQConstants ;
-import org.apache.jena.sparql.algebra.table.TableData ;
+import org.apache.jena.sparql.algebra.table.TableN;
 import org.apache.jena.sparql.core.* ;
 import org.apache.jena.sparql.engine.binding.Binding ;
 import org.apache.jena.sparql.expr.Expr ;
@@ -98,7 +98,7 @@ public class Query extends Prologue implements Cloneable, Printable
     public static final int ORDER_UNKNOW              = -3 ;
 
     // VALUES trailing clause
-    protected TableData valuesDataBlock = null ;
+    protected TableN valuesDataBlock = null ;
 
     protected boolean strictQuery = true ;
 
@@ -601,7 +601,7 @@ public Expr allocAggregate(Aggregator agg)
     public void setValuesDataBlock(List<Var> variables, List<Binding> values)
     {
         checkDataBlock(variables, values) ;
-        valuesDataBlock = new TableData(variables, values) ;
+        valuesDataBlock = new TableN(variables, values) ;
     }
 
     private static void checkDataBlock(List<Var> variables, List<Binding> values)

jena-arq/src/main/java/org/apache/jena/query/ResultSet.java

@@ -103,4 +103,8 @@ public default ResultSet materialise() {
     }
 
     public void close();
+
+    default RowSet toRowSet() {
+        return RowSet.adapt(this);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/algebra/Algebra.java

@@ -161,22 +161,27 @@ public static Binding merge(Binding bindingLeft, Binding bindingRight) {
 
         // If compatible, merge. Iterate over variables in right but not in left.
         BindingBuilder b = Binding.builder(bindingLeft);
-        for ( Iterator<Var> vIter = bindingRight.vars() ; vIter.hasNext() ; ) {
-            Var v = vIter.next();
-            Node n = bindingRight.get(v);
+        bindingRight.forEach((v, n) -> {
             if ( !bindingLeft.contains(v) )
                 b.add(v, n);
-        }
+        });
         return b.build();
     }
 
     public static boolean compatible(Binding bindingLeft, Binding bindingRight) {
         // Test to see if compatible: Iterate over variables in left
-        for ( Iterator<Var> vIter = bindingLeft.vars() ; vIter.hasNext() ; ) {
-            Var v = vIter.next();
+        return compatible(bindingLeft, bindingRight, bindingLeft.vars());
+    }
+
+    /** Test to see if bindings are compatible for all variables of the provided iterator. */
+    public static boolean compatible(Binding bindingLeft, Binding bindingRight, Iterator<Var> vars) {
+        while (vars.hasNext() ) {
+            Var v = vars.next();
             Node nLeft = bindingLeft.get(v);
-            Node nRight = bindingRight.get(v);
+            if ( nLeft == null )
+                continue;
 
+            Node nRight = bindingRight.get(v);
             if ( nRight != null && !nRight.equals(nLeft) )
                 return false;
         }

jena-arq/src/main/java/org/apache/jena/sparql/algebra/TableFactory.java

@@ -18,40 +18,57 @@
 
 package org.apache.jena.sparql.algebra;
 
+import java.util.Iterator;
 import java.util.List ;
 
+import org.apache.jena.atlas.iterator.Iter;
 import org.apache.jena.graph.Node ;
 import org.apache.jena.sparql.algebra.table.Table1 ;
 import org.apache.jena.sparql.algebra.table.TableEmpty ;
 import org.apache.jena.sparql.algebra.table.TableN ;
 import org.apache.jena.sparql.algebra.table.TableUnit ;
 import org.apache.jena.sparql.core.Var ;
 import org.apache.jena.sparql.engine.QueryIterator ;
+import org.apache.jena.sparql.engine.binding.Binding;
+import org.apache.jena.sparql.exec.RowSet;
 
 public class TableFactory
 {
     public static Table createUnit()
     { return new TableUnit() ; }
-    
+
     public static Table createEmpty()
     { return new TableEmpty() ; }
 
     public static Table create()
     { return new TableN() ; }
-    
+
     public static Table create(List<Var> vars)
     { return new TableN(vars) ; }
-    
+
     public static Table create(QueryIterator queryIterator)
-    { 
+    {
         if ( queryIterator.isJoinIdentity() ) {
             queryIterator.close();
             return createUnit() ;
         }
-        
+
         return new TableN(queryIterator) ;
     }
 
     public static Table create(Var var, Node value)
     { return new Table1(var, value) ; }
+
+    /** Creates a mutable table from the detached bindings of the row set. */
+    public static Table create(RowSet rs)
+    {
+        List<Var> vars = rs.getResultVars();
+        Iterator<Binding> it = Iter.map(rs, Binding::detach);
+        return create(vars, it);
+    }
+
+    public static Table create(List<Var> vars, Iterator<Binding> bindings) {
+        List<Binding> list = Iter.toList(bindings);
+        return new TableN(vars, list);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/algebra/table/TableData.java

@@ -18,23 +18,21 @@
 
 package org.apache.jena.sparql.algebra.table ;
 
+import java.util.Collections;
 import java.util.List ;
 
 import org.apache.jena.sparql.ARQException ;
 import org.apache.jena.sparql.core.Var ;
 import org.apache.jena.sparql.engine.binding.Binding ;
 
+/** Immutable table. */
 public class TableData extends TableN {
     public TableData(List<Var> variables, List<Binding> rows) {
-        super(variables, rows) ;
+        super(Collections.unmodifiableList(variables), Collections.unmodifiableList(rows)) ;
     }
 
     @Override
     public void addBinding(Binding binding) {
         throw new ARQException("Can't add bindings to an existing data table") ;
     }
-
-    public List<Binding> getRows() {
-        return rows ;
-    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/algebra/table/TableN.java

@@ -21,13 +21,15 @@
 import java.util.ArrayList ;
 import java.util.Iterator ;
 import java.util.List ;
+import java.util.Objects;
 
 import org.apache.jena.sparql.core.Var ;
 import org.apache.jena.sparql.engine.ExecutionContext ;
 import org.apache.jena.sparql.engine.QueryIterator ;
 import org.apache.jena.sparql.engine.binding.Binding ;
 import org.apache.jena.sparql.engine.iterator.QueryIterPlainWrapper ;
 
+/** Mutable table. */
 public class TableN extends TableBase {
     protected List<Binding> rows = new ArrayList<>() ;
     protected List<Var>     vars = new ArrayList<>() ;
@@ -48,16 +50,13 @@ public TableN(QueryIterator qIter) {
         materialize(qIter) ;
     }
 
-    protected TableN(List<Var> variables, List<Binding> rows) {
-        this.vars = variables ;
-        this.rows = rows ;
+    public TableN(List<Var> variables, List<Binding> rows) {
+        this.vars = Objects.requireNonNull(variables) ;
+        this.rows = Objects.requireNonNull(rows) ;
     }
 
     private void materialize(QueryIterator qIter) {
-        while (qIter.hasNext()) {
-            Binding binding = qIter.nextBinding() ;
-            addBinding(binding) ;
-        }
+        qIter.forEachRemaining(this::addBinding);
         qIter.close() ;
     }
 
@@ -105,4 +104,8 @@ public List<String> getVarNames() {
     public List<Var> getVars() {
         return vars ;
     }
+
+    public List<Binding> getRows() {
+        return rows;
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/Binding.java

@@ -90,4 +90,11 @@ public default boolean contains(String varName) {
 
     @Override
     public boolean equals(Object other);
+
+    /**
+     * Returns a binding which is guaranteed to be independent of
+     * any resources such as an ongoing query execution or a disk-based dataset.
+     * May return itself if it is already detached.
+     */
+    public Binding detach();
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/Binding0.java

@@ -51,4 +51,9 @@ protected void forEach1(BiConsumer<Var, Node> action) { }
 
     @Override
     protected Node get1(Var var) { return null; }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        return new Binding0(newParent);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/Binding1.java

@@ -70,4 +70,9 @@ protected Node get1(Var v) {
             return value;
         return null;
     }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        return new Binding1(newParent, var, value);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/Binding2.java

@@ -77,4 +77,9 @@ protected Node get1(Var v)
             return value2;
         return null;
     }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        return new Binding2(newParent, var1, value1, var2, value2);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/Binding3.java

@@ -132,4 +132,9 @@ protected Node get1(Var var) {
 
         return null;
     }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        return new Binding3(newParent, var1, value1, var2, value2, var3, value3);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/Binding4.java

@@ -154,4 +154,9 @@ protected Node get1(Var var) {
 
         return null;
     }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        return new Binding4(newParent, var1, value1, var2, value2, var3, value3, var4, value4);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/BindingBase.java

@@ -202,4 +202,19 @@ public static int hashCode(Binding bind) {
         }
         return hash;
     }
+
+    @Override
+    public Binding detach() {
+        Binding newParent = parent == null ? null : parent.detach();
+        Binding result = newParent == parent
+                ? detachWithOriginalParent()
+                : detachWithNewParent(newParent);
+        return result;
+    }
+
+    protected Binding detachWithOriginalParent() {
+        return this;
+    }
+
+    protected abstract Binding detachWithNewParent(Binding newParent);
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/BindingOverMap.java

@@ -61,4 +61,9 @@ protected int size1() {
     protected boolean isEmpty1() {
         return map.isEmpty();
     }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        return new BindingOverMap(newParent, map);
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/BindingProject.java

@@ -35,4 +35,17 @@ public BindingProject(Collection<Var> vars, Binding bind) {
     protected boolean accept(Var var) {
         return projectionVars.contains(var) ;
     }
+
+    @Override
+    public Binding detach() {
+        Binding b = binding.detach();
+        return b == binding
+            ? this
+            : new BindingProject(projectionVars, b);
+    }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        throw new UnsupportedOperationException("Should never be called.");
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/BindingProjectBase.java

@@ -25,13 +25,13 @@
 import org.apache.jena.graph.Node ;
 import org.apache.jena.sparql.core.Var ;
 
-/** Common framework for projection; 
+/** Common framework for projection;
  * the projection policy is provided by
- * abstract method {@link #accept(Var)} 
+ * abstract method {@link #accept(Var)}
  */
 public abstract class BindingProjectBase extends BindingBase {
     private List<Var>     actualVars = null ;
-    private final Binding binding ;
+    protected final Binding binding ;
 
     public BindingProjectBase(Binding bind) {
         super(null) ;

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/BindingProjectNamed.java

@@ -33,4 +33,17 @@ public BindingProjectNamed(Binding bind) {
     protected boolean accept(Var var) {
         return var.isNamedVar() ;
     }
+
+    @Override
+    public Binding detach() {
+        Binding b = binding.detach();
+        return b == binding
+            ? this
+            : new BindingProjectNamed(b);
+    }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        throw new UnsupportedOperationException("Should never be called.");
+    }
 }

jena-arq/src/main/java/org/apache/jena/sparql/engine/binding/BindingRoot.java

@@ -33,4 +33,9 @@ private BindingRoot() {
     public void format1(StringBuilder sBuff) {
         sBuff.append("[Root]");
     }
+
+    @Override
+    protected Binding detachWithNewParent(Binding newParent) {
+        return this;
+    }
 }