Return Boolean value from Neo4j cypher query - java

I would like to check whether a node exists using its name (instead of its ID). The Cypher query looks like :
MATCH (c:Jaguar{name:"JLR 2.5Ltr"})-[:REPRESENTED_BY]->(v) RETURN c IS NOT NULL
However, Using neo4j shell/web console, the result returned is of type String. The same fails in spring-data-neo4j with error :
Null return value from advice does not match primitive return type for: public abstract boolean xxx.yyy.repository.SomeRepository.checkIfDatasetExists(java.lang.String)
Has somebody come across any work around for this

The answer provided by Supamiu will not work unfortunately, you need to hack this by returning a count expression :
MATCH (c:Jaguar{name:"JLR 2.5Ltr"})-[:REPRESENTED_BY]->(v)
RETURN count(c) > 0 as c

You should use CASE to check if your node is null or not, and return the value you need :
MATCH (c:Jaguar{name:"JLR 2.5Ltr"})-[:REPRESENTED_BY]->(v)
RETURN CASE WHEN c IS NULL THEN false ELSE true END as c
More informations can be found on Neo4j's Documentation

It is supported now in the latest version, you can use the predicate functions:
exists()
MATCH (c:Jaguar{name:"JLR 2.5Ltr"})
RETURN exists((c)-[:REPRESENTED_BY]->(v)) // returns boolean
Docs

Related

Hamcrest matchers to check JSON filed value is null or empty?

I am using hamcrest for first time, i have developed a framework to validate particular JSON field values need to satisfy some business rules, i am trying to check on of the field in JSON should not be " " or null. Please find below for the code,matcherOperator validate JSON field against a Array of values for example in ISINARRAY validate the JSON filed is present in the following list of array values [1,2,3,4] similarly NOTINARRAY validate the JSON filed should not be present given range of array values. I am trying to check whether given field is empty or null i defined array like this [null,""] and using NOTINARRAY to check JSON key value shouldn't be null or "" for null its working but the JSON value is "" its validating to true and i tried using Matchers.blankOrNullString() too but its not working and i saw two question of similar type but they are part of JUNIT testing which i tried to used but not working below are the question i referred
Hamcrest matcher with slashes is interpreted as a part of validation
Hamcrest check if value is null or empty array
public <T extends Comparable<T>> Matcher<String> mymatcher(final FieldOperator matcherOperator,
final List<String> value)
{
switch (matcherOperator) {
case ISINARRAY: {
return Matchers.in(value);
}
case NOTINARRAY: {
return Matchers.not(Matchers.in(value));
}
}
I am not sure where i am doing wrong please help me in solving the issue.

Set NULL value in jooq

I have an big query and my problem is setting NULL values using jooq.
For example, I have this piece of sql query:
IF(t.PANEL_ID IS NULL, t.ID, NULL) AS testId
If transform this into jooq implementation something like this will come out:
when(TEST.PANEL_ID.isNull(), TEST.ID).otherwise(null)).as("testId")
but this is ambiguous method call.
I made some research, and find this snippet:
DSL.val((String) null)
but it didn't work, because it cannot resolve method with jooq.Param<String>.
How should I proceed?
Your NULL expression must be of the same type as your TEST.ID column. I would imagine this is not a String column, but some numeric one. Irrespective of the actual data type, you can always create a bind value using the data type of another expression, e.g.
// Bind variable:
DSL.val(null, TEST.ID)
// Inline value / NULL literal
DSL.inline(null, TEST.ID)
If you're doing this a lot, you could also extract your own utility like this:
public static <T> util(Field<?> nullable, Field<T> other) {
return when(nullable.isNull(), other).otherwise(inline(null, other));
}
Notice, jOOQ has a built-in method NVL2 for this purpose:
nvl2(TEST.PANEL_ID, inline(null, TEST.ID), TEST.ID).as("testId")

Validating user input UUID [duplicate]

How to check if variable contains valid UUID/GUID identifier?
I'm currently interested only in validating types 1 and 4, but it should not be a limitation to your answers.
Currently, UUID's are as specified in RFC4122. An often neglected edge case is the NIL UUID, noted here. The following regex takes this into account and will return a match for a NIL UUID. See below for a UUID which only accepts non-NIL UUIDs. Both of these solutions are for versions 1 to 5 (see the first character of the third block).
Therefore to validate a UUID...
/^[0-9a-f]{8}-[0-9a-f]{4}-[0-5][0-9a-f]{3}-[089ab][0-9a-f]{3}-[0-9a-f]{12}$/i
...ensures you have a canonically formatted UUID that is Version 1 through 5 and is the appropriate Variant as per RFC4122.
NOTE: Braces { and } are not canonical. They are an artifact of some systems and usages.
Easy to modify the above regex to meet the requirements of the original question.
HINT: regex group/captures
To avoid matching NIL UUID:
/^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
If you want to check or validate a specific UUID version, here are the corresponding regexes.
Note that the only difference is the version number, which is explained in 4.1.3. Version chapter of UUID 4122 RFC.
The version number is the first character of the third group : [VERSION_NUMBER][0-9A-F]{3} :
UUID v1 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[1][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i
UUID v2 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[2][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i
UUID v3 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[3][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i
UUID v4 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[4][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i
UUID v5 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[5][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i
regex to the rescue
/^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$/.test('01234567-9ABC-DEF0-1234-56789ABCDEF0');
or with brackets
/^\{?[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}‌​\}?$/
If you are using Node.js for development, it is recommended to use a package called Validator. It includes all the regexes required to validate different versions of UUID's plus you get various other functions for validation.
Here is the npm link: Validator
var a = 'd3aa88e2-c754-41e0-8ba6-4198a34aa0a2'
v.isUUID(a)
true
v.isUUID('abc')
false
v.isNull(a)
false
If you use the uuid package, this package brings a boolean validation function where it tells you if a uuid is valid or not.
Example:
import { validate as isValidUUID } from 'uuid';
if (!isValidUUID(tx.originId)) {
return Promise.reject('Invalid OriginID');
}
thanks to #usertatha with some modification
function isUUID ( uuid ) {
let s = "" + uuid;
s = s.match('^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$');
if (s === null) {
return false;
}
return true;
}
Beside Gambol's answer that will do the job in nearly all cases, all answers given so far missed that the grouped formatting (8-4-4-4-12) is not mandatory to encode GUIDs in text. It's used extremely often but obviously also a plain chain of 32 hexadecimal digits can be valid.[1] regexenh:
/^[0-9a-f]{8}-?[0-9a-f]{4}-?[1-5][0-9a-f]{3}-?[89ab][0-9a-f]{3}-?[0-9a-f]{12}$/i
[1] The question is about checking variables, so we should include the user-unfriendly form as well.
Why are there dashes in a .NET GUID? - Stack Overflow plus Accepted answer
Test and validate a GUID (guid.us)
Guid.ToString Method (String) (MSDN)
All type-specific regexes posted so far are failing on the "type 0" Nil UUID, defined in 4.1.7 of the RFC as:
The nil UUID is special form of UUID that is specified to have all 128 bits set to zero: 00000000-0000-0000-0000-000000000000
To modify Wolf's answer:
/^[0-9a-f]{8}-?[0-9a-f]{4}-?[0-5][0-9a-f]{3}-?[089ab][0-9a-f]{3}-?[0-9a-f]{12}$/i
Or, to properly exclude a "type 0" without all zeros, we have the following (thanks to Luke):
/^(?:[0-9a-f]{8}-?[0-9a-f]{4}-?[1-5][0-9a-f]{3}-?[89ab][0-9a‌​-f]{3}-?[0-9a-f]{12}‌​|00000000-0000-0000-‌​0000-000000000000)$/‌​i
if you use the uuid package, you can import the validate and pass the id into it
const { v4: uuidv4, validate } = require('uuid');
const { id } = request.params;
validate(id) ? true : false;
I think Gambol's answer is almost perfect, but it misinterprets the RFC 4122 § 4.1.1. Variant section a bit.
It covers Variant-1 UUIDs (10xx = 8..b), but does not cover Variant-0 (0xxx = 0..7) and Variant-2 (110x = c..d) variants which are reserved for backward compatibility, so they are technically valid UUIDs. Variant-4 (111x = e..f) is indeed reserved for future use, so they are not valid currently.
Also, 0 type is not valid, that "digit" is only allowed to be 0 if it's a NIL UUID (like mentioned in Evan's answer).
So I think the most accurate regex that complies with current RFC 4122 specification is (including hyphens):
/^([0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[0-9a-d][0-9a-f]{3}-[0-9a-f]{12}|00000000-0000-0000-0000-000000000000)$/i
^ ^^^^^^
(0 type is not valid) (only e..f variant digit is invalid currently)
A slightly modified version of the above answers written in a more concise way. This will validate any GUID with hyphens (however easily modified to make hyphens optional). This will also support upper and lower case characters which has become the convention regardless of the specification:
/^([0-9a-fA-F]{8})-(([0-9a-fA-F]{4}\-){3})([0-9a-fA-F]{12})$/i
The key here is the repeating part below
(([0-9a-fA-F]{4}\-){3})
Which simply repeats the 4 char patterns 3 times
If someone is using yup , JavaScript schema validator library, This functionality can be achieved with below code.
const schema = yup.object().shape({
uuid: yup.string().uuid()
});
const isValid = schema.isValidSync({uuid:"string"});
Use the .match() method to check whether String is UUID.
public boolean isUUID(String s){
return s.match("^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$");
}
A good way to do it in Node is to use the ajv package (https://github.com/epoberezkin/ajv).
const Ajv = require('ajv');
const ajv = new Ajv({ allErrors: true, useDefaults: true, verbose: true });
const uuidSchema = { type: 'string', format: 'uuid' };
ajv.validate(uuidSchema, 'bogus'); // returns false
ajv.validate(uuidSchema, 'd42a8273-a4fe-4eb2-b4ee-c1fc57eb9865'); // returns true with v4 GUID
ajv.validate(uuidSchema, '892717ce-3bd8-11ea-b77f-2e728ce88125'); // returns true with a v1 GUID
Versions 1 to 5, without using a multi-version regex when version is omitted.
const uuid_patterns = {
1: /^[0-9A-F]{8}-[0-9A-F]{4}-1[0-9A-F]{3}-[0-9A-F]{4}-[0-9A-F]{12}$/i,
2: /^[0-9A-F]{8}-[0-9A-F]{4}-2[0-9A-F]{3}-[0-9A-F]{4}-[0-9A-F]{12}$/i,
3: /^[0-9A-F]{8}-[0-9A-F]{4}-3[0-9A-F]{3}-[0-9A-F]{4}-[0-9A-F]{12}$/i,
4: /^[0-9A-F]{8}-[0-9A-F]{4}-4[0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i,
5: /^[0-9A-F]{8}-[0-9A-F]{4}-5[0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i
};
const isUUID = (input, version) => {
if(typeof input === "string"){
if(Object.keys(uuid_patterns).includes(typeof version === "string" ? version : String(version))){
return uuid_patterns[version].test(input);
} else {
return Object.values(uuid_patterns).some(pattern => pattern.test(input));
}
}
return false;
}
// Testing
let valid = [
'A987FBC9-4BED-3078-CF07-9141BA07C9F3',
'A987FBC9-4BED-4078-8F07-9141BA07C9F3',
'A987FBC9-4BED-5078-AF07-9141BA07C9F3',
];
let invalid = [
'',
'xxxA987FBC9-4BED-3078-CF07-9141BA07C9F3',
'A987FBC9-4BED-3078-CF07-9141BA07C9F3xxx',
'A987FBC94BED3078CF079141BA07C9F3',
'934859',
'987FBC9-4BED-3078-CF07A-9141BA07C9F3',
'AAAAAAAA-1111-1111-AAAG-111111111111',
];
valid.forEach(test => console.log("Valid case, result: "+isUUID(test)));
invalid.forEach(test => console.log("Invalid case, result: "+isUUID(test)));
I added a UUID validator to Apache Commons Validator. It's not yet been merged, but you can vote for it here:
https://github.com/apache/commons-validator/pull/68
I have this function, but it's essentially the same as the accepted answer.
export default function isUuid(uuid: string, isNullable: boolean = false): boolean {
return isNullable
? /^[0-9a-f]{8}-[0-9a-f]{4}-[0-5][0-9a-f]{3}-[089ab][0-9a-f]{3}-[0-9a-f]{12}$/i.test(uuid)
: /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i.test(uuid);
}
I think a better way is using the static method fromString to avoid those regular expressions.
id = UUID.randomUUID();
UUID uuid = UUID.fromString(id.toString());
Assert.assertEquals(id.toString(), uuid.toString());
On the other hand
UUID uuidFalse = UUID.fromString("x");
throws java.lang.IllegalArgumentException: Invalid UUID string: x

Can we get single object from hql query?

I am writing a select query in hql , my task is to activate the bus. First I will get a messege from client as busId#busStatus, so first I look for this perticular busId is active or inactive So I have to write select query but in hibernate query.list() returns list. Here I think list is unnecessary , a single object is enough .
Here is my code ,
String hql="from BusDetailBean where Busid= :busId and bus_status=:busStatus";
Query query = session.createQuery(hql);
query.setParameter("busId", busId);
query.setParameter("busStatus", busStatus);
List<BusDetailBean> busDetails=(List<BusDetailBean>)query.list();
if(busDetails.isEmpty())
{
//my other stuff
}
else
{
//bus ativation stuff
}
My question is the select query returns only one object if list is not empty I have to use for loop in else part. So how can I optimise this code. can anyone help me in this.
You can use query.getSingleResult()
You can use query.setMaxResults(1);
You can get the object at index 0 in the list:
List l = query.list()
if (l.size()>0) {
return l.get(0)
}
I don't think persitence should be mixed with business logic.
What about returning Optional from the persitence layer and whether result is present/absent do something in higher level?
In persistance layer something like:
return query.list()
.stream()
.findFirst()
This, according to docs, will return first result or empty optional if the collection was empty.
And then:
Optional<Bus> optionalBus = repository.find(busId, busStatus);
if (optionalBus.isPresent()) {
something here
} else {
something else
}
by using query.uniqueResult() you don't ensure that if you have many results , then you will get only one of them.
With uniqueResult() you place a guard/contraint at your result set to be aware that this query should always return a unique result.
For this type of problem, the out of the box solution in Hibernate is to use the uniqueResult() method in the Query class:
public Object uniqueResult()
From the Hibernate JavaDocs:
Convenience method to return a single instance that matches the query,
or null if the query returns no results.
Returns: the single result or null
Throws:
NonUniqueResultException - if there is more than one matching result
HibernateException

Empty field in native facet script

I have a native facet script that checks if a specific field (mapped to type long) in the document is empty, this is how I do it:
Object fieldValue = doc().get("fieldName");
return fieldValue == ScriptDocValues.EMPTY;
However, for some of the documents this returns false even when the field is empty (I've checked this with the exists filter). This behavior is inconsistent and it usually returns the correct result. Furthermore, the same document in a different host with the same mapping, same version and same code - returns the correct result.
Is there a better way to check if a field is empty?
I'm using ElasticSearch 0.90.5 with facet script 1.1.2 and java 1.7u17.
The correct way to check for an empty field is:
ScriptDocValues value = (ScriptDocValues) doc().get("field2");
return value.isEmpty();

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