Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/oswaldobapvicjr/jep-data-extension
An extension of the Java Expression Parser library with useful functions for data handling
https://github.com/oswaldobapvicjr/jep-data-extension
data-manipulation java jep jsonpath regular-expression xpath
Last synced: about 2 months ago
JSON representation
An extension of the Java Expression Parser library with useful functions for data handling
- Host: GitHub
- URL: https://github.com/oswaldobapvicjr/jep-data-extension
- Owner: oswaldobapvicjr
- License: apache-2.0
- Created: 2018-11-28T15:03:32.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2024-04-06T03:31:51.000Z (10 months ago)
- Last Synced: 2024-04-06T04:25:50.731Z (10 months ago)
- Topics: data-manipulation, java, jep, jsonpath, regular-expression, xpath
- Language: Java
- Size: 540 KB
- Stars: 4
- Watchers: 1
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
Awesome Lists containing this project
README
# jep-data-extension
[](https://github.com/oswaldobapvicjr/jep-data-extension/actions/workflows/maven.yml)
[](https://codecov.io/gh/oswaldobapvicjr/jep-data-extension)
[](https://maven-badges.herokuapp.com/maven-central/net.obvj/jep-data-extension)
[](https://javadoc.io/doc/net.obvj/jep-data-extension)
**jep-data-extension** is a project that extends JEP, the powerful mathematical expression parser and evaluator for Java, introducing data manipulation capabilities with custom functions and operators ready to use, including **RegEx**, **XPath**, **JSONPath** and **Web Services**.
> For details about JEP core features, access [JEP documentation](http://www.singularsys.com/jep/doc/html/index.html).
---
## New functions
Package
Name
Description
String functions
camel
Converts a string to camel case
concat
Concatenates the arguments into a string.
endsWith
Returns 1 (true) if a string ends with the specified suffix.
findMatch
Returns the first match of the given regular expression found inside a string.
findMatches
Returns a list containing all matches of the given regular expression inside a string.
formatString
Returns a formatted string according to given pattern and variable arguments.
lpad/leftPad
Left-pads a string to a given size.
lcase/lower
Converts a text string to all lower-case letters.
matches
Returns a 1 if the given string contains at least one match of a given RegEx.
normalizeString
Normalizes a Unicode string, replacing accents and other diacritics with ASCII chars.
proper
Converts a string to proper case, i.e., only the first letter in each word in upper-case.
replace
Replaces all occurrences of a given string with another one.
replaceRegex
Replaces all matches of a given regular expression.
rpad/rightPad
Right-pads a string to a given size.
split
Splits a string into a string array based on a separating string or regular expression.
startsWith
Returns 1 if a string starts a given prefix.
trim
Removes leading and trailing spaces.
ucase/upper
Converts a text string to all upper-case letters.
Date functions
now/sysdate
Returns the system's current date & time.
str2date
Converts a string into date by trying different patterns such as RFC-3339, RFC-822 and common ISO-8601 variations.
date2str
Converts a date into string using a specified format.
daysBetween
Returns the number of days between two dates.
endOfMonth
Returns a date corresponding to the last day of the month given a source date.
isLeapYear
Returns 1 if the given date or year number is a leap year, i.e., an year with 366 days.
year
Returns the year for a given date.
quarter
Returns the quarter of the year for a given date.
month
Returns the month for a given date, a number starting from 1 (Jan) to 12 (Dec).
isoWeekNumber
Returns the ISO week number for a given date.
weekday
Returns the day of the week of a date, a number from 1 (Sunday) to 7 (Saturday).
day
Returns the day of the month for a given date..
hour
Returns the hour of day for a given date, as a number from 0 (12AM) to 23 (11PM).
minute
Returns the minute within the hour for a given date, as a number from 0 to 59.
second
Returns the seconds within the minute for a given date, a number from 0 to 59.
addDays
Returns the result from adding a number of days to a date.
Math functions
arabic
Converts a Roman numeral to Arabic.
roman
Converts an Arabic numeral to Roman.
Data manipulation & filtering
xpath
Returns the result of the given XPath expression at the specified XML.
jsonpath
Returns the result of the given JSONPath expression at the specified JSON.
Statistical functions
average
Returns the average of the elements inside a given array, JSON array or collection (including valid representations).
count
Returns the number of elements inside a given array, JSON array or collection (including valid string representations).
max
Returns the largest value in a given array, JSON array or collection (including valid string representations).
min
Returns the smallest value in a given array, JSON array or collection (including valid string representations).
Random
uuid
Produces a randomly generated type 4 UUID (Universally-unique Identifier) string.
Utility functions
distinct
Returns a list consisting of the distinct elements of a given list, array or JSON array.
getEnv
Returns the value of an environment variable.
getSystemProperty
Returns the value of system property.
isDecimal
Returns 1 if the given parameter is a number (including strings) containing decimals.
isEmpty
Returns 1 if a given parameter is either null or an empty String, JSON or collection.
isInteger
Returns 1 if the given number (or valid string) represents a whole number, i.e, which lacks decimals.
readFile
Returns the content of a text file in the file system.
typeOf/class
Returns the Java type associated with the given variable.
Cryptography functions
sha256
Computes the SHA-256 hash of the given string and transforms the binary result into a hexadecimal string.
toBase64
Encodes a string to Base64 encoding scheme.
fromBase64
Decodes a Base64 encoded string.
Web Services
httpGet
Returns data from a Web Service or RESTful API, as string.
http
Invokes a specific method towards a Web Service/REST API.
httpHeader
This function groups a variable number of HTTP header entries for usage with other HTTP functions.
basicAuthorizationHeader
Generates a basic authorization header from a given username and password.
httpStatusCode
Returns the HTTP status code of a given WebServiceResponse.
httpResponse
Returns the HTTP response body from given WebServiceResponse, as string.
> ℹ️ [Find examples in the wiki.](https://github.com/oswaldobapvicjr/jep-data-extension/wiki)
---
## Custom operators
JEP offers a good set of operators for common arithmetic and logical operations, for example: addition (`+`), subtraction (`-`), multiplication (`*`), division (`/`), modulus (`%`), power (`^`), "Boolean And" (`&&`), "Boolean Or" (`||`), and "Boolean Not" (`!`). These operators can be used when required and are supported by JEP.
### Comparative operators
Standard JEP relational operators accept only numerical variables (including string representation of non-complex, numerical values). These operators have been overloaded to allow comparison of dates, as well as string representations of valid dates:
- Less than (`<`)
- Less than or equal to (`<=`)
- Greater than (`>`)
- Greater than or equal to (`<=`)
- Equal (`==`)
- Not equal (`!=`)
This allows the usage of dates in expressions that can be evaluated to `true` or `false`. For example:
```java
if("2017-03-11T10:15:00:123Z" < now(), "past", "not past")
```
### Element operator
Standard "element" operator (`[]`) was overloaded to support data extraction out of JSON arrays and other collections by index.
```java
jsonArray[1] //extracts the first element of the given jsonArray
```
> **Note:** Also achievable using the function `get(jsonArray, 1)`.
---
## How to include it
If you are using Maven, add **jep-data-extension** as a dependency to your pom.xml file.
```xml
net.obvj
jep-data-extension
1.0.7
```
If you use other dependency managers (such as Gradle, Grape, Ivy, etc.) click [here](https://search.maven.org/artifact/net.obvj/jep-data-extension).
---
## How to use it
### Example 1: replacing characters from a text variable using the `JEPContextFactory`
1. Add `jep-data-extensions` to your class path
2. Put your source variables in a map:
```java
Map myVariables = new HashMap<>();
myVariables.put("myText", "foo");
```
3. Use the `JEPContextFactory` class to create an extended JEP object with all available extensions:
````java
JEP jep = JEPContextFactory.newContext(myVariables);
````
> **Note:** Alternatively, you may use the `JEPContextFactory.newContext()` to receive a new context with no initial variables. You may add them later, calling `jep.addVariable(String, Object)`.
4. Parse your expression:
````java
Node node = jep.parseExpresion("replace(myText, \"oo\", \"ee\")");
````
5. Evaluate the expression with JEP's `evaluate` method:
````java
String result = (String) jep.evaluate(node); //result = "fee"
````
6. Alternatively, you can use the assignment operator inside an expression. The new variable will be available in JEP context for reuse and can be retrieved using the `getVarValue` method:
````java
Node node = jep.parseExpression("myText = replace(\"fear\", \"f\", \"d\")"));
jep.evaluate(node);
String result = (String) jep.getVarValue("myText"); //result = "dear"
````
### Example 2: comparing dates using the `ExpressionEvaluatorFacade`
The `ExpressionEvaluatorFacade` is a convenient object to quickly parse a single expression. A single call to the `evaluate` method will create a new evaluation context and return the expression result directly. It accepts a map with initial variables for use in the operation.
1. Put your source variables in a map:
```java
Map myVariables = new HashMap<>();
myVariables.put("date1", "2018-12-20T09:10:00.123456789Z");
```
2. Evaluate your expression:
````java
String expression = "if(date1 < now(), \"overdue\", \"not overdue\")";
String result = (String) ExpressionEvaluatorFacade.evaluate(expression, myVariables);
//result = "overdue"
````
### Example 3: Consuming data from a RESTful API using the Evaluation Console
1. Run `jep-data-extension` JAR file from a terminal:
```
$ java -jar jep-data-extension-1.0.2.jar
```
2. Consume the RESTful API with the `httpGet` function:
```
JEP > dateTime = httpGet("http://date.jsontest.com/")
{
"time": "08:31:19 PM",
"date": "05-12-2012"
}
```
3. Filter the JSON using a JsonPath expression that extracts the date field:
```
JEP > date = jsonpath(dateTime, "$.date")
05-12-2012
```
3. Check the type of the generated `date` variable:
```
JEP > class(date)
java.lang.String
```
4. Convert the string to Date:
```
JEP > date = str2date(date, "dd-MM-yyyy")
Wed Dec 05 00:00:00 BRST 2012
```
5. Extract the week number from the converted date:
```
JEP > isoWeekNumber(date)
49
```