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Version: 1.2.x

Class: Message

Events traversing layline.io Workflows are instantiated as a Message. This class exposes a number of properties and methods to extract and set data within messages.

To understand the anatomy of a message please read the respective chapter in the documentation.

Example Message Structure​

Assume we have the following data dictionary structure

  • Header
    • IOT
      • RECORD_TYPE
      • DEVICE_NO
  • Detail
    • IOT
      • RECORD_TYPE
      • TIME
      • MEASUREMENT
  • Trailer
    • IOT
      • RECORD_TYPE
      • COUNT

Then in a Javascript processor we can do this:

...
export function onMessage() {
    if (message.type.Header) {
        onHeader (message);
    } else if (message.type.Detail) {
        onDetail(message);
    } else if (message.type.Trailer) {
        onDetail(message);
    }

    // send the message on through OUTPUT_PORT of Processor
    stream.emit(message, OUTPUT_PORT);
}
...

And this:

...
// Handle a detail record type
onDetail (message) {
    const m = message.data.IOT.MEASUREMENT;

    const VENDOR = Status.getVendorByName('MyVendorLongName');

    if (m < 0) {
         message.addStatus(Severity.ERROR, Status.create(VENDOR, 'ILLEGAL_MEASUREMENT', m));
    }
}
...

Properties​

data​

data: object

Methods​

addStatus()​

addStatus(severity, status, addToLog?): void

Adds a Status to a message. The Status must have been created with Status.create or otherwise instantiated.

Parameters​

• severity: Severity

Severity value.

• status: Status

The Status which should be added.

• addToLog?: boolean= true

Signals whether the Status shall also be added to the log, or not. Will be added by default if not specified. If true then the Status will be visible in the Stream Log of the Audit Trail.

Returns​

void

Example​

 if (error) {
     message.addStatus(Severity.ERROR, Status.create(VENDOR, 'ILLEGAL_VALUE', valueString));
 }

clone()​

clone(): Message

Creates a full clone of a Message

clonedMessage = message.clone();

Returns​

Message

A copy of a Message

exists()​

exists(entityDeclaration): boolean

Checks if a known data structure is recognized within a given Message. Data structures are spawned into existence by the definition of data formats (Format Assets). You can test a particular Message on whether a specific structure is present within a message by using this method.

This is typically used to check whether a message is of a certain type, or not.

Parameters​

• entityDeclaration: EntityDeclaration

The Path to data dictionary structure which you want to test for existence in the message (EntityDeclaration.)

Returns​

boolean

True, if it exists, else false.

Example​

// Get the access path to a structure within the compiled data dictionary
const MY_RECORD_TYPE = dataDictionary.type.MyFormat.Detail;

// Test message against the existence of the data dictionary structure.
if (message.exists(MY_RECORD_TYPE)) {
    ...
}

findStatus()​

findStatus(callback): Status

Check whether a message carries a specified status.

const VENDOR = Status.getVendorByName('MyVendorLongName');

const foundStatusArray = detail.findStatus(function(status) { ",
     // Code 9 means 'DISCARD'",
     return status.vendorId === VENDOR.id && status.code === 9; ",
 });",

Parameters​

• callback: Function

Returns​

Status

  • Array of found States. Empty array if nothing found.

getBigInteger()​

getBigInteger(accessor): Uint8Array

Return a BigInteger typed value from a message field. Important!: Please note that this method returns a Java object "Big Integer" (a Java native data type). Because of this you cannot reliably use simple Javascript number operators without risking implicit conversion errors.

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

Uint8Array

Number in Java native BigInteger type.

Example​

const n = message.getBigInteger(dataDictionary.type.Detail.CSV.A_REALLY_BIG_NUMBER_FIELD);

// Compare BigInteger to another BigInteger
const BigInteger = Java.type("java.math.BigInteger");
x = new BigInteger(123); // x now a java type BigInteger

x == 123; // -> "true", via implicit conversion --> be careful here, because x will be implicitly be converted to JS number and may lose precision
x.equals(123); // -> "false", because comparing different data types (BigInteger / Number)
x.equals(new BigInteger(123)); // -> "true"

getBoolean()​

getBoolean(accessor, defaultValue?): Boolean

Return the Boolean typed value from a message field. Important!: Please note that this method returns a Java object "Boolean" (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• defaultValue?: boolean

Default value if no Boolean value could be retrieved from message.

Returns​

Boolean

Number in Java native Boolean type.

Example​

const b = message.getBoolean(dataDictionary.type.Detail.CSV.A_BOOLEAN_FIELD);

getByte()​

getByte(accessor): Byte

Return the Byte typed value from a message field. Important!: Please note that this method returns a Java object "Byte" (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

Byte

Java native Byte type.

Example​

const b = message.getByte(dataDictionary.type.Detail.CSV.A_BYTE_FIELD);

getByteString()​

getByteString(accessor): ByteString

Return the ByteString typed value from a message field. Important!: Please note that this method returns a "ByteString" typed value (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

ByteString

ByteString type.

Example​

const b = message.getByteString(dataDictionary.type.Detail.CSV.FIELD);

getCharacter()​

getCharacter(accessor): Character

Return a Character typed value from a message field. Important!: Please note that this method returns a "char" typed value (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

Character

Character in Java native char type.

Example​

const c = message.getCharacter(dataDictionary.type.Detail.CSV.FIELD);

getCrc64()​

getCrc64(message): string

Creates a CRC 64 checksum from specified node within a Message.

Parameters​

• message: MessageNode

MessageNode for which to create the CRC64 checksum.

Returns​

string

CRC 64 checksum

Example​

const crc64 = message.getCrc64(message.data.CSV);

getDateTime()​

getDateTime(accessor): OffsetDateTime

Return a OffsetDateTime typed value from a message field. Important!: Please note that this method returns a "OffsetDateTime" typed value (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

OffsetDateTime

A date-time with an offset from UTC/Greenwich in the ISO-8601 calendar system, such as "2022-12-03T10:15:30+01:00".

Example​

const dt = message.getDateTime(dataDictionary.type.Detail.CSV.FIELD);

getDecimal()​

getDecimal(accessor): BigDecimal

Return a BigDecimal typed value from a message field. Important!: Please note that this method returns a "BigDecimal" typed value (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

BigDecimal

BigDecimal in Java native char type.

Example​

const dec = message.getDecimal(dataDictionary.type.Detail.CSV.FIELD);

getDouble()​

getDouble(accessor): Double

Return a Double typed value from a message field. Important!: Please note that this method returns a "Double" typed value (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

Double

Double in Java native char type.

Example​

const dbl = message.getDouble(dataDictionary.type.Detail.CSV.FIELD);

getInt()​

getInt(accessor): Integer

Return a Int typed value from a message field. Important!: Please note that this method returns a "Integer" typed value (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

Integer

Integer in Java native char type.

Example​

const int = message.getInt(dataDictionary.type.Detail.CSV.FIELD);

getLong()​

getLong(accessor): Long

Return a Long typed value from a message field. Important!: Please note that this method returns a "Long" typed value (a Java native data type).

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

Long

Long in Java native char type.

Example​

const l = message.getLong(dataDictionary.type.Detail.CSV.FIELD);

getMessageDigest()​

getMessageDigest(algorithm?, toLowerCase?, accessorArray?): string

Returns a calculated digest for a given message

Parameters​

• algorithm?: string

Algorithm with which to calculate the digest. Currently only supports "MD5".

• toLowerCase?: boolean= false

Set to true if digest should be lower-case only.

• accessorArray?: EntityDeclaration[]

Array of EntityDeclaration on which to calculate the digest.

Returns​

string

Example​


// Option: 1. Return digest considering complete message content.
// Digest calculation defaults to MD5 hash and no lower case.
const md5DigestFull = message.getMessageDigest();

// Option: 2. Return digest for full message content based on MD5 hash.
// Returned digest will be lower case only.
const md5DigestFullLower = message.getMessageDigest("MD5", true);

// Option: 3. Calculate digest considering specific data structures within message only.
recordAccessorForMD5 = [
    dataDictionary.type.Detail.CSV.RECORD_TYPE,
    dataDictionary.type.Detail.CSV.LAST_NAME,
    dataDictionary.type.Detail.CSV.FIRST_NAME
]

const md5Digest = message.getMessageDigest("MD5", true, recordAccessorForMD5);

getNumStatusAttached()​

getNumStatusAttached(): void

Gets the number of States Status attached.

const result = message.getNumStatusAttached();

Returns​

void

  • Number of States attached to the message.

getObject()​

getObject(accessor): Object

Return a Object value a message field.

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

Object

Object in Java native char type.

Example​

const o = message.getObject(dataDictionary.type.Detail.CSV.FIELD);

getStatus()​

getStatus(index): Status

Retrieves a Status by index from the list of States attached to a message. A message keeps track of related States in a Status array attached to it. This list may be empty or filled with one more States.

Parameters​

• index: number

Index of Status to retrieve.

Returns​

Status

  • Status or undefined if no Status found with that index.

Example​

// Retrieve the first Status from the list of States attached to the message.
const status = message.getStatus(0);

getString()​

getString(accessor): String

Return a String typed value from a message field.

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

Returns​

String

The value as string.

Example​

const l = message.getLong(dataDictionary.type.Detail.CSV.FIELD);

hasStatusAttached()​

hasStatusAttached(severity): void

Checks if a message has a Status attached which matches a particular Severity.

const result = message.hasStatusAttached(Severity.ERROR);

Parameters​

• severity: Severity

Severity to check against.

Returns​

void

  • True, if match found, else false.

pack()​

pack(): PackedMessage

Packs the message into a memory efficient format.

// Pack message
const packedMsg = message.pack();

// Unpack message
const unpackedMsg = packedMsg.unpack();

Returns​

PackedMessage

  • Packed message.

setBigInteger()​

setBigInteger(accessor, value): void

Sets a BigInteger value in a message target field.

const BigInteger = Java.type("java.math.BigInteger");
bigInt = new BigInteger(123); // x now a java type BigInteger

message.setBigInteger(dataDictionary.type.Detail.CSV.FIELD, bigInt)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: Uint8Array

A native BigInteger value or a value which can be implicitly converted to such.

Returns​

void

setBoolean()​

setBoolean(accessor, value): void

Sets a Boolean value in a message target field.

message.setBoolean(dataDictionary.type.Detail.CSV.FIELD, true)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: Boolean

A native Byte value or a value which can be implicitly converted to such.

Returns​

void

setByte()​

setByte(accessor, value): void

Sets a Byte value in a message target field.

const Byte = Java.type("java.math.Byte");
b = new Byte(123); // b now a java type Byte

message.setByte(dataDictionary.type.Detail.CSV.FIELD, b)
// or
message.setByte(dataDictionary.type.Detail.CSV.FIELD, 7)
// or
message.setByte(dataDictionary.type.Detail.CSV.FIELD, 'X')

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: string | number

A native Byte value or a value which can be implicitly converted to such.

Returns​

void

setByteString()​

setByteString(accessor, value): void

Sets a ByteString value in a message target field.

const ByteString = Java.type("java.math.ByteString");
b = new ByteString("XYZ"); // b now a java type ByteString

message.setByteString(dataDictionary.type.Detail.CSV.FIELD, b)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: string

A native ByteString value or a value which can be implicitly converted to such.

Returns​

void

setCharacter()​

setCharacter(accessor, value): void

Sets a Character value in a message target field.

message.setCharacter(dataDictionary.type.Detail.CSV.FIELD, 'c')

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: Character

A native Character value or a value which can be implicitly converted to such.

Returns​

void

setDateTime()​

setDateTime(accessor, value): void

Sets a OffsetDateTime value in a message target field.

message.setCharacter(dataDictionary.type.Detail.CSV.FIELD, "2022-12-03T10:15:30+01:00")

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: OffsetDateTime

A date-time with an offset from UTC/Greenwich in the ISO-8601 calendar system, such as "2022-12-03T10:15:30+01:00".

Returns​

void

setDecimal()​

setDecimal(accessor, value): void

Sets a Decimal value in a message target field. Internally represented as a Java BigDecimal. Will try to infer result from passed value.

message.setDecimal(dataDictionary.type.Detail.CSV.FIELD, 123.45)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: BigDecimal | BigInteger | Double | Integer | Long | Number | String

A value which can be represented as a Decimal.

Returns​

void

setDouble()​

setDouble(accessor, value): void

Sets a Double value in a message target field. Internally represented as a Java Double. Will try to infer result from passed value.

message.setDouble(dataDictionary.type.Detail.CSV.FIELD, 123.45)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: Number | BigDecimal | BigInteger | Double | Integer | Long | String

A value which can be represented as a Double.

Returns​

void

setInt()​

setInt(accessor, value): void

Sets a Int value in a message target field. Internally represented as a Java Int. Will try to infer result from passed value.

message.setInt(dataDictionary.type.Detail.CSV.FIELD, 123)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: Number | Uint8Array | BigDecimal | Double | Integer | Long | String

A value which can be represented as a Int.

Returns​

void

setLong()​

setLong(accessor, value): void

Sets a Long value in a message target field. Internally represented as a Java Long. Will try to infer result from passed value.

message.setLong(dataDictionary.type.Detail.CSV.FIELD, 12345)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: BigDecimal | BigInteger | Double | Integer | Long | Number | String

A value which can be represented as a Long.

Returns​

void

setObject()​

setObject(accessor, value): void

Sets a Object value in a message target field.

const obj = [1, 2, 3, 4, 5];
message.setObject(dataDictionary.type.Detail.CSV.FIELD, obj)

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: Object

A value which can be represented as a Object.

Returns​

void

setString()​

setString(accessor, value): void

Sets a Object value in a message target field.

message.setString(dataDictionary.type.Detail.CSV.FIELD, "XYZ")
// or simply
message.data.CSV.FIELD = "XYZ"

Parameters​

• accessor: EntityDeclaration

EntityDeclaration describing the access path to the field value.

• value: Object

A value which can be represented as a String.

Returns​

void

toString()​

toString(): void

Returns the message in a string representation.

Returns​

void

Example​

stream.logInfo("Current message: " + message.toString());