| /* |
| * 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.sparql.core ; |
| |
| import java.util.ArrayList ; |
| import java.util.Collection ; |
| import java.util.List ; |
| |
| import org.apache.jena.graph.Node ; |
| import org.apache.jena.graph.Node_Variable ; |
| import org.apache.jena.sparql.ARQConstants ; |
| import org.apache.jena.sparql.ARQInternalErrorException ; |
| import org.apache.jena.sparql.engine.binding.Binding ; |
| import org.apache.jena.sparql.expr.ExprVar ; |
| import org.apache.jena.sys.JenaSystem; |
| |
| /** A SPARQL variable */ |
| |
| public class Var extends Node_Variable |
| { |
| // This class create Nodes (as Vars) |
| static { JenaSystem.init(); } |
| |
| /* Variable used to indicate "don't bind" |
| * Each use is unique. |
| */ |
| |
| // Legal SPARQL variable name but note it must be exactly this |
| // object, not just the same name, to be anonymous. |
| public static Var ANON = new Var("?_") ; |
| |
| public static Var alloc(String varName) { |
| // if ( varName.equals("_") ) |
| // return ANON ; |
| return new Var(varName) ; |
| } |
| |
| public static Var alloc(Node_Variable v) // asVar? |
| { |
| if ( v instanceof Var ) |
| return (Var)v; |
| return new Var(v); |
| } |
| |
| public static Var alloc(Node v) { |
| if ( v instanceof Var ) |
| return (Var)v; |
| if ( v instanceof Node_Variable ) |
| return new Var((Node_Variable)v); |
| throw new NotAVariableException("Node: " + v); |
| } |
| |
| public static Var alloc(Var v) { |
| return v; |
| } |
| |
| public static Var alloc(ExprVar nv) { return new Var(nv) ; } |
| |
| /** Return the value in the binding (if node is a Var) or the node itself. */ |
| public static Node lookup(Binding binding, Node node) { |
| if ( !Var.isVar(node) ) |
| return node; |
| Var var = Var.alloc(node); |
| return lookup(binding, var); |
| } |
| |
| /** Return the value in the binding or the variable itself. */ |
| public static Node lookup(Binding binding, Var var) { |
| Node n = binding.get(var); |
| if ( n != null ) |
| return n; |
| return var; |
| } |
| |
| // Precalulated the hash code because hashCode() is used so heavily with Var's |
| private final int hashCodeValue ; |
| |
| private Var(String varName) { super(varName) ; hashCodeValue = super.hashCode() ; } |
| |
| private Var(Node_Variable v) { this(v.getName()) ; } |
| |
| private Var(ExprVar v) { this(v.getVarName()) ; } |
| |
| // Not needed |
| public Node asNode() { return this ; } |
| |
| public String getVarName() { return getName() ; } |
| |
| static class NotAVariableException extends ARQInternalErrorException { |
| NotAVariableException(String msg) { super(msg) ; } |
| } |
| |
| @Override |
| public final int hashCode() { return hashCodeValue ; } |
| |
| @Override |
| public final boolean equals(Object other) { |
| if ( this == other ) return true ; |
| if ( ! ( other instanceof Var ) ) return false ; |
| return super.equals(other) ; |
| } |
| |
| // @Override |
| // public String toString() { return node.toString() ; } |
| |
| public boolean isNamedVar() { return isNamedVarName(getName()) ; } |
| |
| public boolean isBlankNodeVar() { return isBlankNodeVarName(getName()) ; } |
| |
| public boolean isAllocVar() { return isAllocVarName(getName()) ; } |
| |
| public boolean isAnonVar() { return isAnonVar(this) ; } |
| |
| // ------- |
| |
| public static String canonical(String x) { |
| if ( x.startsWith("?") ) |
| return x.substring(1); |
| if ( x.startsWith("$") ) |
| return x.substring(1); |
| return x; |
| } |
| |
| public static boolean isVar(Node node) { |
| if ( node instanceof Var ) |
| return true; |
| if ( node != null && node.isVariable() ) |
| throw new NotAVariableException("Node_Variable (not a Var) found"); |
| return false; |
| } |
| |
| public static boolean isRenamedVar(Node node) |
| { return node.isVariable() && isRenamedVar(node.getName()) ; } |
| |
| public static boolean isRenamedVar(String x) |
| { return x.startsWith(ARQConstants.allocVarScopeHiding) ; } |
| |
| public static boolean isNamedVar(Node node) |
| { return node.isVariable() && isNamedVarName(node.getName()) ; } |
| |
| public static boolean isNamedVarName(String x) |
| { return ! isBlankNodeVarName(x) && ! isAllocVarName(x) ; } |
| |
| public static boolean isBlankNodeVar(Node node) |
| { return node.isVariable() && isBlankNodeVarName(node.getName()) ; } |
| |
| public static boolean isBlankNodeVarName(String x) |
| { return x.startsWith(ARQConstants.allocVarAnonMarker) ; } |
| |
| public static boolean isAllocVar(Node node) |
| { return node.isVariable() && isAllocVarName(node.getName()) ; } |
| |
| public static boolean isAllocVarName(String x) |
| { return x.startsWith(ARQConstants.allocVarMarker) ; } |
| |
| /** Convert a collection of variable names to variables */ |
| public static List<Var> varList(Collection<String> varNames) { |
| List<Var> x = new ArrayList<>(); |
| for ( String obj : varNames ) |
| x.add(Var.alloc(obj)); |
| return x; |
| } |
| |
| public static boolean isAnonVar(Var var) { |
| return var == ANON; |
| } |
| |
| /** Return a list of String names from a collection of variables */ |
| public static List<String> varNames(Collection<Var> vars) { |
| List<String> x = new ArrayList<>(); |
| for ( Var var : vars ) |
| x.add(var.getVarName()); |
| return x; |
| } |
| } |