Golang TripleStore.NodesAllIterator方法代碼示例

func buildIteratorFromValue(val otto.Value, ts graph.TripleStore) graph.Iterator {
	if val.IsNull() || val.IsUndefined() {
		return ts.NodesAllIterator()
	}
	if val.IsPrimitive() {
		thing, _ := val.Export()
		switch v := thing.(type) {
		case string:
			it := ts.FixedIterator()
			it.Add(ts.ValueOf(v))
			return it
		default:
			glog.Errorln("Trying to build unknown primitive value.")
		}
	}
	switch val.Class() {
	case "Object":
		return buildIteratorTree(val.Object(), ts)
	case "Array":
		// Had better be an array of strings
		strings := makeListOfStringsFromArrayValue(val.Object())
		it := ts.FixedIterator()
		for _, x := range strings {
			it.Add(ts.ValueOf(x))
		}
		return it
	case "Number":
		fallthrough
	case "Boolean":
		fallthrough
	case "Date":
		fallthrough
	case "String":
		it := ts.FixedIterator()
		str, _ := val.ToString()
		it.Add(ts.ValueOf(str))
		return it
	default:
		glog.Errorln("Trying to handle unsupported Javascript value.")
		return iterator.NewNull()
	}
}

func buildInOutIterator(obj *otto.Object, ts graph.TripleStore, base graph.Iterator, isReverse bool) graph.Iterator {
	argList, _ := obj.Get("_gremlin_values")
	if argList.Class() != "GoArray" {
		glog.Errorln("How is arglist not an array? Return nothing.", argList.Class())
		return iterator.NewNull()
	}
	argArray := argList.Object()
	lengthVal, _ := argArray.Get("length")
	length, _ := lengthVal.ToInteger()
	var predicateNodeIterator graph.Iterator
	if length == 0 {
		predicateNodeIterator = ts.NodesAllIterator()
	} else {
		zero, _ := argArray.Get("0")
		predicateNodeIterator = buildIteratorFromValue(zero, ts)
	}
	if length >= 2 {
		var tags []string
		one, _ := argArray.Get("1")
		if one.IsString() {
			s, _ := one.ToString()
			tags = append(tags, s)
		} else if one.Class() == "Array" {
			tags = makeListOfStringsFromArrayValue(one.Object())
		}
		for _, tag := range tags {
			predicateNodeIterator.Tagger().Add(tag)
		}
	}

	in, out := quad.Subject, quad.Object
	if isReverse {
		in, out = out, in
	}
	lto := iterator.NewLinksTo(ts, base, in)
	and := iterator.NewAnd()
	and.AddSubIterator(iterator.NewLinksTo(ts, predicateNodeIterator, quad.Predicate))
	and.AddSubIterator(lto)
	return iterator.NewHasA(ts, and, out)
}

func buildIteratorTreeHelper(obj *otto.Object, ts graph.TripleStore, base graph.Iterator) graph.Iterator {
	var it graph.Iterator
	it = base
	// TODO: Better error handling
	kindVal, _ := obj.Get("_gremlin_type")
	stringArgs := getStringArgs(obj)
	var subIt graph.Iterator
	prevVal, _ := obj.Get("_gremlin_prev")
	if !prevVal.IsObject() {
		subIt = base
	} else {
		subIt = buildIteratorTreeHelper(prevVal.Object(), ts, base)
	}

	kind, _ := kindVal.ToString()
	switch kind {
	case "vertex":
		if len(stringArgs) == 0 {
			it = ts.NodesAllIterator()
		} else {
			fixed := ts.FixedIterator()
			for _, name := range stringArgs {
				fixed.Add(ts.ValueOf(name))
			}
			it = fixed
		}
	case "tag":
		it = subIt
		for _, tag := range stringArgs {
			it.Tagger().Add(tag)
		}
	case "save":
		all := ts.NodesAllIterator()
		if len(stringArgs) > 2 || len(stringArgs) == 0 {
			return iterator.NewNull()
		}
		if len(stringArgs) == 2 {
			all.Tagger().Add(stringArgs[1])
		} else {
			all.Tagger().Add(stringArgs[0])
		}
		predFixed := ts.FixedIterator()
		predFixed.Add(ts.ValueOf(stringArgs[0]))
		subAnd := iterator.NewAnd()
		subAnd.AddSubIterator(iterator.NewLinksTo(ts, predFixed, quad.Predicate))
		subAnd.AddSubIterator(iterator.NewLinksTo(ts, all, quad.Object))
		hasa := iterator.NewHasA(ts, subAnd, quad.Subject)
		and := iterator.NewAnd()
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "saver":
		all := ts.NodesAllIterator()
		if len(stringArgs) > 2 || len(stringArgs) == 0 {
			return iterator.NewNull()
		}
		if len(stringArgs) == 2 {
			all.Tagger().Add(stringArgs[1])
		} else {
			all.Tagger().Add(stringArgs[0])
		}
		predFixed := ts.FixedIterator()
		predFixed.Add(ts.ValueOf(stringArgs[0]))
		subAnd := iterator.NewAnd()
		subAnd.AddSubIterator(iterator.NewLinksTo(ts, predFixed, quad.Predicate))
		subAnd.AddSubIterator(iterator.NewLinksTo(ts, all, quad.Subject))
		hasa := iterator.NewHasA(ts, subAnd, quad.Object)
		and := iterator.NewAnd()
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "has":
		fixed := ts.FixedIterator()
		if len(stringArgs) < 2 {
			return iterator.NewNull()
		}
		for _, name := range stringArgs[1:] {
			fixed.Add(ts.ValueOf(name))
		}
		predFixed := ts.FixedIterator()
		predFixed.Add(ts.ValueOf(stringArgs[0]))
		subAnd := iterator.NewAnd()
		subAnd.AddSubIterator(iterator.NewLinksTo(ts, predFixed, quad.Predicate))
		subAnd.AddSubIterator(iterator.NewLinksTo(ts, fixed, quad.Object))
		hasa := iterator.NewHasA(ts, subAnd, quad.Subject)
		and := iterator.NewAnd()
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "morphism":
		it = base
	case "and":
		arg, _ := obj.Get("_gremlin_values")
		firstArg, _ := arg.Object().Get("0")
		if !isVertexChain(firstArg.Object()) {
			return iterator.NewNull()
		}
		argIt := buildIteratorTree(firstArg.Object(), ts)

		and := iterator.NewAnd()
//.........這裏部分代碼省略.........

func buildIteratorTree(tree *peg.ExpressionTree, ts graph.TripleStore) graph.Iterator {
	switch tree.Name {
	case "Start":
		return buildIteratorTree(tree.Children[0], ts)
	case "NodeIdentifier":
		var out graph.Iterator
		nodeID := getIdentString(tree)
		if tree.Children[0].Name == "Variable" {
			allIt := ts.NodesAllIterator()
			allIt.AddTag(nodeID)
			out = allIt
		} else {
			n := nodeID
			if tree.Children[0].Children[0].Name == "ColonIdentifier" {
				n = nodeID[1:]
			}
			fixed := ts.FixedIterator()
			fixed.Add(ts.ValueOf(n))
			out = fixed
		}
		return out
	case "PredIdentifier":
		i := 0
		if tree.Children[0].Name == "Reverse" {
			//Taken care of below
			i++
		}
		it := buildIteratorTree(tree.Children[i], ts)
		lto := iterator.NewLinksTo(ts, it, graph.Predicate)
		return lto
	case "RootConstraint":
		constraintCount := 0
		and := iterator.NewAnd()
		for _, c := range tree.Children {
			switch c.Name {
			case "NodeIdentifier":
				fallthrough
			case "Constraint":
				it := buildIteratorTree(c, ts)
				and.AddSubIterator(it)
				constraintCount++
				continue
			default:
				continue
			}
		}
		return and
	case "Constraint":
		var hasa *iterator.HasA
		topLevelDir := graph.Subject
		subItDir := graph.Object
		subAnd := iterator.NewAnd()
		isOptional := false
		for _, c := range tree.Children {
			switch c.Name {
			case "PredIdentifier":
				if c.Children[0].Name == "Reverse" {
					topLevelDir = graph.Object
					subItDir = graph.Subject
				}
				it := buildIteratorTree(c, ts)
				subAnd.AddSubIterator(it)
				continue
			case "PredicateKeyword":
				switch c.Children[0].Name {
				case "OptionalKeyword":
					isOptional = true
				}
			case "NodeIdentifier":
				fallthrough
			case "RootConstraint":
				it := buildIteratorTree(c, ts)
				l := iterator.NewLinksTo(ts, it, subItDir)
				subAnd.AddSubIterator(l)
				continue
			default:
				continue
			}
		}
		hasa = iterator.NewHasA(ts, subAnd, topLevelDir)
		if isOptional {
			optional := iterator.NewOptional(hasa)
			return optional
		}
		return hasa
	default:
		return &iterator.Null{}
	}
	panic("Not reached")
}