Golang iterator.NewNull函数代码示例

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本文整理汇总了Golang中github.com/google/cayley/graph/iterator.NewNull函数的典型用法代码示例。如果您正苦于以下问题：Golang NewNull函数的具体用法？Golang NewNull怎么用？Golang NewNull使用的例子？那么恭喜您, 这里精选的函数代码示例或许可以为您提供帮助。

在下文中一共展示了NewNull函数的8个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于我们的系统推荐出更棒的Golang代码示例。

示例1: buildIteratorTree

func buildIteratorTree(obj *otto.Object, qs graph.QuadStore) graph.Iterator {
	if !isVertexChain(obj) {
		return iterator.NewNull()
	}
	path := buildPathFromObject(obj)
	if path == nil {
		return iterator.NewNull()
	}
	return path.BuildIteratorOn(qs)
}

开发者ID:e4x，项目名称:cayley，代码行数:10，代码来源:build_iterator.go

示例2: buildIteratorFromValue

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()
	}
}

开发者ID:jacqui，项目名称:cayley，代码行数:42，代码来源:build_iterator.go

示例3: buildInOutIterator

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)
}

开发者ID:jacqui，项目名称:cayley，代码行数:40，代码来源:build_iterator.go

示例4: optimizeLinksTo

func (qs *QuadStore) optimizeLinksTo(it *iterator.LinksTo) (graph.Iterator, bool) {
	subs := it.SubIterators()
	if len(subs) != 1 {
		return it, false
	}
	primary := subs[0]
	switch primary.Type() {
	case graph.Fixed:
		size, _ := primary.Size()
		if size == 0 {
			return iterator.NewNull(), true
		}
		if size == 1 {
			if !graph.Next(primary) {
				panic("sql: unexpected size during optimize")
			}
			val := primary.Result()
			newIt := qs.QuadIterator(it.Direction(), val)
			nt := newIt.Tagger()
			nt.CopyFrom(it)
			for _, tag := range primary.Tagger().Tags() {
				nt.AddFixed(tag, val)
			}
			it.Close()
			return newIt, true
		} else if size > 1 {
			var vals []string
			for graph.Next(primary) {
				vals = append(vals, qs.NameOf(primary.Result()))
			}
			lsql := &SQLLinkIterator{
				constraints: []constraint{
					constraint{
						dir:  it.Direction(),
						vals: vals,
					},
				},
				tableName: newTableName(),
				size:      0,
			}
			l := &SQLIterator{
				uid: iterator.NextUID(),
				qs:  qs,
				sql: lsql,
			}
			nt := l.Tagger()
			nt.CopyFrom(it)
			for _, t := range primary.Tagger().Tags() {
				lsql.tagdirs = append(lsql.tagdirs, tagDir{
					dir: it.Direction(),
					tag: t,
				})
			}
			it.Close()
			return l, true
		}
	case sqlType:
		p := primary.(*SQLIterator)
		newit, err := linksto(p.sql, it.Direction(), qs)
		if err != nil {
			glog.Errorln(err)
			return it, false
		}
		newit.Tagger().CopyFrom(it)
		return newit, true
	case graph.All:
		linkit := &SQLLinkIterator{
			tableName: newTableName(),
			size:      qs.Size(),
		}
		for _, t := range primary.Tagger().Tags() {
			linkit.tagdirs = append(linkit.tagdirs, tagDir{
				dir: it.Direction(),
				tag: t,
			})
		}
		for k, v := range primary.Tagger().Fixed() {
			linkit.tagger.AddFixed(k, v)
		}
		linkit.tagger.CopyFrom(it)
		newit := NewSQLIterator(qs, linkit)
		return newit, true
	}
	return it, false
}

开发者ID:e4x，项目名称:cayley，代码行数:85，代码来源:optimizers.go

示例5: buildIteratorTree

func buildIteratorTree(obj *otto.Object, ts graph.TripleStore) graph.Iterator {
	if !isVertexChain(obj) {
		return iterator.NewNull()
	}
	return buildIteratorTreeHelper(obj, ts, iterator.NewNull())
}

开发者ID:jacqui，项目名称:cayley，代码行数:6，代码来源:build_iterator.go

示例6: buildIteratorTreeHelper

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()
//.........这里部分代码省略.........

开发者ID:jacqui，项目名称:cayley，代码行数:101，代码来源:build_iterator.go

示例7: buildIteratorTreeHelper

func buildIteratorTreeHelper(obj *otto.Object, qs graph.QuadStore, base graph.Iterator) graph.Iterator {
	// TODO: Better error handling
	var (
		it    graph.Iterator
		subIt graph.Iterator
	)

	if prev, _ := obj.Get("_gremlin_prev"); !prev.IsObject() {
		subIt = base
	} else {
		subIt = buildIteratorTreeHelper(prev.Object(), qs, base)
	}

	stringArgs := propertiesOf(obj, "string_args")
	val, _ := obj.Get("_gremlin_type")
	switch val.String() {
	case "vertex":
		if len(stringArgs) == 0 {
			it = qs.NodesAllIterator()
		} else {
			fixed := qs.FixedIterator()
			for _, name := range stringArgs {
				fixed.Add(qs.ValueOf(name))
			}
			it = fixed
		}
	case "tag":
		it = subIt
		for _, tag := range stringArgs {
			it.Tagger().Add(tag)
		}
	case "save":
		all := qs.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 := qs.FixedIterator()
		predFixed.Add(qs.ValueOf(stringArgs[0]))
		subAnd := iterator.NewAnd(qs)
		subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
		subAnd.AddSubIterator(iterator.NewLinksTo(qs, all, quad.Object))
		hasa := iterator.NewHasA(qs, subAnd, quad.Subject)
		and := iterator.NewAnd(qs)
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "saver":
		all := qs.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 := qs.FixedIterator()
		predFixed.Add(qs.ValueOf(stringArgs[0]))
		subAnd := iterator.NewAnd(qs)
		subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
		subAnd.AddSubIterator(iterator.NewLinksTo(qs, all, quad.Subject))
		hasa := iterator.NewHasA(qs, subAnd, quad.Object)
		and := iterator.NewAnd(qs)
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "has":
		fixed := qs.FixedIterator()
		if len(stringArgs) < 2 {
			return iterator.NewNull()
		}
		for _, name := range stringArgs[1:] {
			fixed.Add(qs.ValueOf(name))
		}
		predFixed := qs.FixedIterator()
		predFixed.Add(qs.ValueOf(stringArgs[0]))
		subAnd := iterator.NewAnd(qs)
		subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
		subAnd.AddSubIterator(iterator.NewLinksTo(qs, fixed, quad.Object))
		hasa := iterator.NewHasA(qs, subAnd, quad.Subject)
		and := iterator.NewAnd(qs)
		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(), qs)

		and := iterator.NewAnd(qs)
//.........这里部分代码省略.........

开发者ID:oliverp19，项目名称:cayley，代码行数:101，代码来源:build_iterator.go

示例8: buildIteratorTree

func (p *pathObject) buildIteratorTree() graph.Iterator {
	if p.path == nil {
		return iterator.NewNull()
	}
	return p.path.BuildIteratorOn(p.wk.qs)
}

开发者ID:dennwc，项目名称:cayley，代码行数:6，代码来源:traversals.go

注：本文中的github.com/google/cayley/graph/iterator.NewNull函数示例整理自Github/MSDocs等源码及文档管理平台，相关代码片段筛选自各路编程大神贡献的开源项目，源码版权归原作者所有，传播和使用请参考对应项目的License；未经允许，请勿转载。