Version
JavaBeanReader
Short Description
JavaBeanReader reads a JavaBeans hierarchical structure which is stored in a dictionary. This allows dynamic data interchange between CloverDX graphs and external environment, such as the cloud. The dictionary you are reading to serves as an interface between the outer (e.g. the cloud) and inner worlds (CloverDX).
| Component | Data source | Input ports | Output ports | Each to all outputs | Different to different outputs | Transformation | Transf. req. | Java | CTL | Auto-propagated metadata |
|---|---|---|---|---|---|---|---|---|---|---|
JavaBeanReader |
dictionary |
0 |
1-n |
⨯ |
✓ |
⨯ |
⨯ |
⨯ |
⨯ |
✓ |
Ports
| Port type | Number | Required | Description | Metadata |
|---|---|---|---|---|
Output |
0 |
✓ |
Successfully read records. |
Any |
1-n |
Connect other output ports if your mapping requires it. |
Successfully read records. |
Any. Each port can have different metadata. |
Metadata
JavaBeanReader does not propagate metadata.
JavaBeanReader has no metadata template.
JavaBeanReader Attributes
| Attribute | Req | Description | Possible values |
|---|---|---|---|
Basic |
|||
Dictionary source |
yes |
The dictionary you want to read JavaBeans from. |
The name of a dictionary you have previously defined. |
Data policy |
Determines the action after an error on reading occurs. For more information, see Data Policy. |
Strict (default) | Controlled | Lenient |
|
Mapping |
Mapping the input JavaBeans structure to output ports. For more information, see JavaBeanReader Mapping Definition. |
||
Mapping URL |
The external text file containing the mapping definition. |
||
Implicit mapping |
By default, you have to manually map input elements even to Clover fields of the same name.
If you switch to |
false (default) | true |
|
Details
JavaBeanReader reads data from JavaBeans through a dictionary. It maps Java attributes / collection elements to output records based on a mapping you define. You do not have to map the whole input file - you use XPath expressions to select only the data you need. The component sends data to different connected output records as defined by your mapping.
The mapping process is similar to the one in XMLReader.
JavaBeanReader Mapping Definition
-
Every Mapping definition consists of
<Context>tags which also contain some attributes and allow mapping of element names to Clover fields. Nested structure of<Context>tags is similar to the nested structure of elements in input JavaBeans. -
Each
<Context>tag can surround a serie of nested<Mapping>tags. These allow to rename JavaBeans elements to Clover fields. However, Mapping does not need to copy the whole input structure, it can start at an arbitrary depth in the tree. -
Each of these
<Context>and<Mapping>tags contains some JavaBeanReader Context Tag Attributes and JavaBeanReader Mapping Tag Attributes, respectively.Example 21. Example Mapping in JavaBeanReader<Context xpath="/employees" outPort="0" sequenceId="empSeq" sequenceField="id"> <Mapping xpath="firstName" cloverField="firstName"/> <Mapping xpath="lastName" cloverField="lastName"/> <Mapping xpath="salary" cloverField="salary"/> <Mapping xpath="jobTitle" cloverField="jobTitle"/> <Context xpath="children" outPort="1" parentKey="id" generatedKey="empID"> <Mapping xpath="name" cloverField="chname"/> <Mapping xpath="age" cloverField="age"/> </Context> <Context xpath="benefits" outPort="2" parentKey="id" generatedKey="empID"> <Mapping xpath="car" cloverField="car"/> <Mapping xpath="cellPhone" cloverField="mobilephone"/> <Mapping xpath="monthlyBonus" cloverField="monthlyBonus"/> <Mapping xpath="yearlyBonus" cloverField="yearlyBonus"/> </Context> <Context xpath="projects" outPort="3" parentKey="id" generatedKey="empID"> <Mapping xpath="name" cloverField="projName"/> <Mapping xpath="manager" cloverField="projManager"/> <Mapping xpath="start" cloverField="Start"/> <Mapping xpath="end" cloverField="End"/> <Mapping xpath="customers" cloverField="customers"/> </Context> </Context>If you switch Implicit mapping to
true, the elements (e.g.salary) will be automatically mapped onto fields of the same name (salary) and you do not have to write:<Mapping xpath="salary" cloverField="salary"/>and you map explicitly only to populate fields with data from distinct elements.
-
JavaBeanReader Context Tags and Mapping Tags
-
Empty Context Tag (Without a Child)
<Context xpath="xpathexpression"JavaBeanReader Context Tag Attributes/> -
Non-Empty Context Tag (Parent with a Child)
<Context xpath="xpathexpression"JavaBeanReader Context Tag Attributes>(nested Context and Mapping elements (only children, parents with one or more children, etc.)</Context> -
Empty Mapping Tag (Renaming Tag)
-
xpathis used:<Mapping xpath="xpathexpression"JavaBeanReader Mapping Tag Attributes/> -
nodeNameis used:<Mapping nodeName="elementname"JavaBeanReader Mapping Tag Attributes/>
-
-
-
JavaBeanReader Context Tag and Mapping Tag Attributes
-
Required
The xpath expression can be any XPath query.
Example:
xpath="/tagA/…/tagJ" -
Optional
The number of output port to which data is sent. If not defined, no data from this level of Mapping is sent out using such level of Mapping.
Example:
outPort="2" -
Both
parentKeyandgeneratedKeymust be specified.A sequence of metadata fields on the next parent level separated by a semicolon, colon, or pipe. The number and data types of all these fields must be the same in the
generatedKeyattribute or all values are concatenated to create a unique string value. In such a case, the key has only one field.Example:
parentKey="first_name;last_name"Equal values of these attributes assure that such records can be joined in the future.
-
Both
parentKeyandgeneratedKeymust be specified.A sequence of metadata fields on the specified level separated by a semicolon, colon, or pipe. The number and data types of all these fields must be the same in the
parentKeyattribute or all values are concatenated to create a unique string value. In such a case, the key has only one field.Example:
generatedKey="f_name;l_name"Equal values of these attributes assure that such records can be joined in the future.
-
When a pair of
parentKeyandgeneratedKeydoes not insure unique identification of records, a sequence can be defined and used.Id of the sequence.
Example:
sequenceId="Sequence0" -
When a pair of
parentKeyandgeneratedKeydoes not insure unique identification of records, a sequence can be defined and used.A metadata field on the specified level in which the sequence values are written. Can serve as
parentKeyfor the next nested level.Example:
sequenceField="sequenceKey"
-
-
Either
xpathornodeNamemust be specified in the<Mapping>tag.XPath query.
Example:
xpath="tagA/…/salary" -
Either
xpathornodeNamemust be specified in the<Mapping>tag. UsingnodeNameis faster than usingxpath.The JavaBeans node that should be mapped to Clover field.
Example:
nodeName="salary" -
Required
Clover field to which the JavaBeans node should be mapped.
The name of the field in the corresponding level.
Example:
cloverFields="SALARY"
Reading Multivalue Fields
As of CloverDX 3.3, reading multivalue fields is supported - you can read only lists, however (see Multivalue Fields).
|
Reading maps is handled as reading pure |
Example 22. Reading lists with JavaBeanReader
An example input file containing a list of three elements: John, Vicky, Brian
can be read back by the component with this mapping:
<Mapping xpath="attendees" cloverField="attendanceList"/>where attendanceList is a field of your metadata.
The metadata has to be assigned to the component’s output edge.
After you run the graph, the field will get populated by data like this (what appears in View data):
[John,Vicky,Brian]
Data conversions in JavaBeanReader
The possible conversions of Java data types to CTL2 data types are described in the following table.
The list in the table means a list of corresponding data type.
Java data types |
CTL2 data types |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Numeric data types |
boolean |
date |
byte |
cbyte |
String |
list |
map |
||||
integer |
long |
number (double) |
decimal |
||||||||
int |
✓ |
✓ |
✓ |
✓ |
- |
⨯ |
- |
- |
✓ |
✓ |
⨯ |
long |
- |
✓ |
✓ |
- |
- |
✓ |
- |
- |
✓ |
✓ |
⨯ |
float |
- |
- |
✓ |
- |
⨯ |
⨯ |
- |
- |
✓ |
✓ |
⨯ |
double |
- |
- |
✓ |
- |
⨯ |
⨯ |
- |
- |
✓ |
✓ |
⨯ |
boolean |
✓ |
✓ |
✓ |
⨯ |
✓ |
⨯ |
- |
- |
✓ |
✓ |
⨯ |
java.util.Date |
⨯ |
✓ |
⨯ |
⨯ |
⨯ |
✓ |
- |
- |
✓ |
✓ |
⨯ |
String |
- |
- |
- |
- |
- |
⨯ |
- |
- |
✓ |
✓ |
⨯ |
array [] |
- |
- |
- |
- |
- |
⨯ |
- |
- |
- |
- |
⨯ |
java.util.Collection |
- |
- |
- |
- |
- |
⨯ |
- |
- |
- |
✓ |
⨯ |
Conversions are explained below:
Java int to CTL2 boolean
Value 0 is converted to false, 1 is converted to true.
If Java int contains other value, the graph fails.
Java int to CTL2 byte or cbyte
The value of the int variable is converted either to a character or to an empty string.
Java long to CTL2 integer
The value of the Java bean long variable can be read to the integer field provided the value is within the range of CTL2 integer.
If the value is out of the range of CTL2 integer, the graph fails.
Java long to CTL2 decimal
The decimal needs to have a sufficient length to contain a value from long data type.
The default length (12) might not be enough for all cases.
Java long to CTL2 boolean
The conversion from Java long to CTL2 boolean works in the same way as conversion from Java int to CTL2 boolean.
0 is converted to false, 1 is converted to true, other values cause a failure.
Java long to CTL2 byte or cbyte
See: Java int to CTL2 byte or cbyte conversion.
Java float to CTL2 integer
Value of the Java float variable can be converted to CTL2 integer.
The value of the float number is being truncated in the conversion.
If the value in float variable is out of range of integer, the conversion fails.
Java float to CTL2 long
The value of the Java float variable can be converted to CTL2 long. The value of the float number is being truncated.
If the value stored in the float variable is positive and out of range of the long data type, the nearest long value is used.
If the value stored in the float variable is negative and out of range of the long data type, the result is null.
Java float to CTL2 decimal
CTL2 decimal needs to have a sufficient length.
If not, the conversion from Java float fails.
Java float to CTL2 byte and cbyte
The value of Java float is trimmed to its integral part and the result value is converted to a character.
If the value is out of range of byte, an empty string is used.
Java double to CTL2 integer
The value of Java double needs to be within range of CTL2 integer.
The value of Java double is truncated to its integral part towards zero.
If the value is out of range, the conversion fails.
Java double to CTL2 long
If the value of Java doubleis within range of CTL2 long, the value is truncated to the nearest integral value towards zero.
If the value of Java double is positive and out of range of CTL2 long, the result is the largest long number (Long.MAX_VALUE). If the value of Java double is negative and out of range of CTL long, the result is null.
Java double to CTL2 decimal
The CTL2 decimal needs to have a sufficient length to contain the value of Java double.
In the case of insufficient length of CTL2 decimal, the conversion fails.
Java double to CTL2 byte and cbyte
The value of Java double is trimmed to its integral part and the result is converted to a character.
If the value is out of range of byte, an empty string is used.
Java boolean to CTL2 byte and cbyte
The value of Java boolean converted to CTL2 byte or cbyte is a single unprintable character.
The character has the code 0 if the input is false or 1 if the input is true.
Java Date to CTL2 byte and cbyte
The value of Java Date converted to byte or cbyte results in an empty string.
Java String to CTL2 integer or long
If the Java String variable contains integral value within range of integer, the number will be converted.
Otherwise the conversion fails.
If the java String variable contains integral value within range of long, the number will be converted to long.
Otherwise the conversion fails.
Java String to CTL2 number (double) or decimal
If the Java String contains a numeric value, the value is converted to number (double) or decimal.
If the Java String does not contain a numeric value, the conversion fails.
Java String to CTL2 boolean
If the Java String contains the value 1, true, True or TRUE, CTL2 boolean will hold true.
If Java String contains the value 0, false, False or FALSE, CTL2 boolean will hold false.
If any other value is present in the Java String, the conversion fails.
Java String to CTL2 byte or cbyte
Java String to byte or cbyte conversion has an empty string as a result.
Java array to CTL2
The conversion of a Java bean array to integer, long, number (double) and decimal has zero as a result.
The result of the conversion from a Java array CTL2 boolean is false.
Java array converted to byte and cbyte is null.
Java Collection to CTL2
The conversion from Java Collection to integer, long, double, decimal, String returns first item of collection.
Collection to byte and cbyte conversion has an empty string as a result.