### Jetty Groovlets Programmatic Setup

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-servlet/src/spec/doc/servlet-userguide.adoc

Example of setting up Groovlets programmatically using Jetty. This demonstrates how to integrate GroovyServlet with a Jetty server instance.

```groovy
import groovy.servlet.GroovyServlet
import org.eclipse.jetty.server.Server

```

--------------------------------

### Setup Event Handler

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_type-checking-extensions.adoc

Handles the 'setup' event, which is called after the type checker finishes initialization. Used for extension setup.

```groovy
def setup() {
    // Perform setup of your extension
}
```

--------------------------------

### Install Groovy using SDKMAN!

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-getting-started.adoc

Use SDKMAN! to easily install Groovy on Bash platforms. Ensure you have SDKMAN! installed and initialized before running the install command.

```shell
$ curl -s "https://get.sdkman.io" | bash
```

```shell
$ source "$HOME/.sdkman/bin/sdkman-init.sh"
```

```shell
$ sdk install groovy
```

```shell
$ groovy -version
```

--------------------------------

### GINQ Multiplication Table Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ example demonstrating how to generate a multiplication table. This example is tagged for inclusion.

```groovy
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_examples_01,indent=0]
```

--------------------------------

### GINQ Window Function Examples

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Demonstrates various window functions in GINQ.

```groovy
def result07 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result08 = sql.eachRow( """
SELECT
    name,
    score,
    RANK() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result01 = sql.eachRow( """
SELECT
    name,
    score,
    DENSE_RANK() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result03 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result05 = sql.eachRow( """
SELECT
    name,
    score,
    LAG(score, 1, 0) OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result06 = sql.eachRow( """
SELECT
    name,
    score,
    LEAD(score, 1, 0) OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result20 = sql.eachRow( """
SELECT
    name,
    score,
    FIRST_VALUE(score) OVER (PARTITION BY name ORDER BY score DESC ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
FROM
    Score
""" )
```

```groovy
def result21 = sql.eachRow( """
SELECT
    name,
    score,
    FIRST_VALUE(score) OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result09 = sql.eachRow( """
SELECT
    name,
    score,
    FIRST_VALUE(score) OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result10 = sql.eachRow( """
SELECT
    name,
    score,
    LAST_VALUE(score) OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result13 = sql.eachRow( """
SELECT
    name,
    score,
    NTH_VALUE(score, 2) OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result16 = sql.eachRow( """
SELECT
    name,
    score,
    NTILE(2) OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result17 = sql.eachRow( """
SELECT
    name,
    score,
    PERCENT_RANK() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result18 = sql.eachRow( """
SELECT
    name,
    score,
    CUME_DIST() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result19 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result12 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result14 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result15 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result11 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

```groovy
def result40 = sql.eachRow( """
SELECT
    name,
    score,
    ROW_NUMBER() OVER (PARTITION BY name ORDER BY score DESC)
FROM
    Score
""" )
```

--------------------------------

### HTML Login Example using Form POST

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-http-builder/src/spec/doc/http-builder.adoc

Combines form submission with HTML parsing to automate a login process. This example demonstrates sending credentials and checking the response.

```groovy
def client = HttpBuilder.http('https://example.com/')
client.form('/login', [username: 'user', password: 'password']) {
    assert status == 200
    // Check for successful login indicator in HTML
    assert html.body().text().contains('Welcome, user!')
}
```

--------------------------------

### Hash Join Example 1

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

An example of a hash join in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_joining_07,indent=0]
```

--------------------------------

### Hash Join Example 3

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A third example of a hash join in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_joining_09,indent=0]
```

--------------------------------

### Hash Join Example 2

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Another example of a hash join in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_joining_08,indent=0]
```

--------------------------------

### Setup for Server-Side Template Rendering (Java)

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-templates/src/spec/doc/_markup-template-engine.adoc

Provides the necessary Java setup for rendering templates on the server side, including creating a template configuration and the template engine instance.

```java
include::../test/MarkupTemplateEngineSpecTest.groovy[tags=rendering_setup,indent=0]
```

--------------------------------

### Spock Specification Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-testing-guide.adoc

A basic Spock specification demonstrating a feature method with setup, when, and then blocks for testing a Stack class.

```groovy
class StackSpec extends Specification {

    def "adding an element leads to size increase"() {  // <1>
        setup: "a new stack instance is created"        // <2>
            def stack = new Stack()

        when:                                           // <3>
            stack.push 42

        then:                                           // <4>
            stack.size() == 1
    }
}
```

--------------------------------

### Array Data Source Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Demonstrates using an array as a data source in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_datasource_02,indent=0]
```

--------------------------------

### Stream Data Source Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Demonstrates using a stream as a data source in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_datasource_01,indent=0]
```

--------------------------------

### Basic Groovy Ant Task Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ant/src/spec/doc/groovy-ant-task.adoc

A simple 'Hello World' example using the Groovy Ant task. This demonstrates the most basic usage.

```xml
<groovy>
println "Hello World"
</groovy>
```

--------------------------------

### Inner Join Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

An example of an inner join in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_joining_01,indent=0]
```

--------------------------------

### JmxBuilder.bean() Syntax Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-jmx/src/spec/doc/jmx.adoc

This is a comprehensive syntax example for the JmxBuilder.bean() node, illustrating various descriptors for MBean configuration.

```groovy
jmx.export {
    bean(
        target:bean instance,
        name:ObjectName,
        desc:"...",
        attributes:"*",
        attributes:[]
        attributes:[ "AttrubuteName1","AttributeName2",...,"AttributeName_n" ]
        attributes:[
            "AttributeName": "*",
            "AttributeName":[
                desc:"...",
                defaultValue:value,
                writable:true|false,
                editable:true|false,
                onChange:{event-> // event handler}
            ]
        ],

        constructors:"*",
        constructors:[
            "Constructor Name":[],
            "Constructor Name":[ "ParamType1","ParamType2,...,ParamType_n" ],
            "Constructor Name":[
                desc:"...",
                params:[
                    "ParamType1": "*",
                    "ParamType2":[desc:"...", name:"..."],...,
                    "ParamType_n":[desc:"...", name:"..."]
                ]
            ]
        ],

        operations:"*",
        operations:[ "OperationName1", "OperationName2",...,"OperationNameN" ],
        operations:[
            "OperationName1": "*",
            "OperationName2":[ "type1","type2,"type3" ]
            "OperationName3":[
                desc:"...",
                params:[
                    "ParamType1": "*"
                    "ParamType2":[desc:"...", name:"..."],...,
                    "ParamType_n":[desc:"...", name:"..."]
                ],
                onInvoked:{event-> JmxBuilder.send(event:"", to:"")}
            ]
        ],

        listeners:[
            "ListenerName1":[event: "...", from:ObjectName, call:{event->}],
            "ListenerName2":[event: "...", from:ObjectName, call:&methodPointer]
        ]

    )
}
```

--------------------------------

### AutoClone Equivalent Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-metaprogramming.adoc

Shows an equivalent implementation of the @AutoClone example without the AST transformation.

```groovy
include::../test/CloningASTTransformsTest.groovy[tags=example_autoclone_equiv,indent=0]
```

--------------------------------

### GINQ Grouping Example 06

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_06,indent=0]
```

--------------------------------

### GINQ Grouping Example 07

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_07,indent=0]
```

--------------------------------

### AutoClone Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-metaprogramming.adoc

Demonstrates the basic usage of the @AutoClone AST transformation.

```groovy
include::../test/CloningASTTransformsTest.groovy[tags=example_autoclone,indent=0]
```

--------------------------------

### FileTreeBuilder Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-domain-specific-languages.adoc

Creates a directory structure using FileTreeBuilder, specifying directories and files.

```groovy
new FileTreeBuilder('src').invokeMethod('dir', [
    'main': {
        dir 'groovy', {
            file 'Foo.groovy'
        }
    },
    'test': {
        dir 'groovy', {
            file 'FooTest.groovy'
        }
    }
])
```

--------------------------------

### Flow Typing Example (Footer)

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-domain-specific-languages.adoc

Completes the flow typing example, showing how @DelegatesTo helps IDEs and type checkers.

```groovy
Greeter greeter = new Greeter()
exec { 
    sayHello() 
}
```

--------------------------------

### Robot Script Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_type-checking-extensions.adoc

A basic Groovy script demonstrating the use of a 'robot' object.

```groovy
def robot = new Robot()
robot.move(10)
robot.turn(90)
```

--------------------------------

### GINQ Aggregation Function Examples

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Demonstrates various aggregation functions in GINQ.

```groovy
def result22 = sql.eachRow( """
SELECT
    name,
    MIN(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result23 = sql.eachRow( """
SELECT
    name,
    MAX(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result26 = sql.eachRow( """
SELECT
    name,
    COUNT(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result27 = sql.eachRow( """
SELECT
    name,
    SUM(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result28 = sql.eachRow( """
SELECT
    name,
    AVG(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result33 = sql.eachRow( """
SELECT
    name,
    MEDIAN(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result31 = sql.eachRow( """
SELECT
    name,
    STDEV(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result32 = sql.eachRow( """
SELECT
    name,
    STDEVP(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result29 = sql.eachRow( """
SELECT
    name,
    VAR(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result30 = sql.eachRow( """
SELECT
    name,
    VARP(score) OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result35 = sql.eachRow( """
SELECT
    name,
    AGG(score, 'MIN') OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result36 = sql.eachRow( """
SELECT
    name,
    AGG(score, 'MAX') OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result37 = sql.eachRow( """
SELECT
    name,
    AGG(score, 'SUM') OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result38 = sql.eachRow( """
SELECT
    name,
    AGG(score, 'AVG') OVER (PARTITION BY name)
FROM
    Score
""" )
```

```groovy
def result42 = sql.eachRow( """
SELECT
    name,
    AGG(score, 'COUNT') OVER (PARTITION BY name)
FROM
    Score
""" )
```

--------------------------------

### Get Help for a Command in Groovy Shell

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-groovysh/src/spec/doc/groovysh.adoc

Use the /help command followed by the command name to get detailed usage information. This example shows how to get help for the /help command itself.

```groovysh
groovy> /help /help
help -  command help
Usage: help [TOPIC...]
  -? --help                      Displays command help
     --groups                    Commands are grouped by registries
  -i --info                      List commands with a short command info
```

--------------------------------

### Displaying the Start of a File with /head

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-groovysh/src/spec/doc/groovysh.adoc

Example of using the /head command to display the first few lines of a file.

```jshell
groovy> /head -n2 fruit.txt
apple
banana
```

--------------------------------

### Groovy AST Transformation: @WithLogging Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-metaprogramming.adoc

Demonstrates a simple local AST transformation to add logging messages at the start and end of method invocations. This example showcases a naive approach to aspect-oriented programming in Groovy.

```groovy
import org.codehaus.groovy.transform.ASTTransformation
import org.codehaus.groovy.ast.*
import org.codehaus.groovy.ast.expr.MethodCallExpr
import org.codehaus.groovy.ast.stmt.BlockStmt
import org.codehaus.groovy.ast.stmt.ExpressionStatement
import org.codehaus.groovy.control.SourceUnit

@interface WithLogging {}

class WithLoggingASTTransformation implements ASTTransformation {
    @Override
    void visit(ASTTransformationCode ast, SourceUnit sourceUnit) {
        ast.methods.each {
            if (it.code != null) {
                def logStart = new MethodCallExpr(new MethodCallExpr(null, "println", new ConstantExpression("Entering method: ${it.name}")),
                                                    "println", new ConstantExpression("Exiting method: ${it.name}"))
                it.code.statements.add(0, new ExpressionStatement(logStart))
            }
        }
    }
}
```

--------------------------------

### Groovy DSL Creation with Maps and Closures (Example 1)

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-domain-specific-languages.adoc

Illustrates a basic strategy for creating a DSL in Groovy using maps and Closures.

```groovy
def builder = [
    "key1": [
        "subkey1": "value1",
        "subkey2": "value2"
    ],
    "key2": [
        "subkey3": "value3"
    ]
]

def result = builder.key1.subkey1
assert result == "value1"
```

--------------------------------

### GINQ Result Set Data Source Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Demonstrates using a GINQ result set as a data source.

```groovy
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_datasource_04,indent=0]
```

--------------------------------

### Groovy Octal Literal Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_working-with-numbers.adoc

Demonstrates the declaration of an octal literal in Groovy, which starts with a '0' followed by octal digits.

```groovy
def o = 012
```

--------------------------------

### Basic vbox Usage

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-swing/src/spec/doc/_swing-builder-widgets.adoc

Demonstrates the fundamental creation of a vbox component using the Swing Builder. No specific setup is required beyond having the Swing Builder available.

```groovy
swing.vbox()
```

--------------------------------

### For Loop Invariant Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-contracts/src/spec/doc/contracts-userguide.adoc

Illustrates how to apply a loop invariant to a for loop using the @Invariant annotation. The condition must hold at the start of each iteration.

```groovy
include::../test/ContractsTest.groovy[tags=loop_invariant_for_example,indent=0]
```

--------------------------------

### Intercept Groovy Property Get

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-metaprogramming.adoc

Override getProperty to intercept read access to properties. This example forwards requests to the getter for all properties except 'field3'.

```groovy
def getProperty(String property) {
    if (property == 'field3') {
        return super.getProperty(property)
    }
    return "Intercepted property: $property"
}
```

--------------------------------

### Groovy Valid Identifiers

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-syntax.adoc

Examples of valid identifiers (variable names) in Groovy, adhering to rules that allow letters, dollar signs, and underscores at the start, followed by letters, numbers, or Unicode characters.

```groovy
def _myVar = 1
def $myVar = 2
def myVar = 3
def myVarÀ = 4
def myVarÖ = 5
def myVarØ = 6
def myVarö = 7
def myVarø = 8
def myVar￾ = 9
def myVar￿ = 10
```

--------------------------------

### SQL Sorting with GINQ

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Demonstrates basic sorting in GINQ, equivalent to SQL ORDER BY.

```sql
select * from T order by name
```

```sql
select * from T order by name asc
```

```sql
select * from T order by name desc
```

--------------------------------

### Groovy Shell /keymap Command Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-groovysh/src/spec/doc/groovysh.adoc

Illustrates the output of the /keymap command, showing key bindings for widgets like tailtip-toggle and autosuggest-toggle.

```shell
groovy> /keymap
...
"^["s tailtip-toggle
"^["v autosuggest-toggle
...
```

--------------------------------

### SQL Pagination with GINQ

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

Illustrates pagination using the limit clause in GINQ, specifying offset and size, or just size.

```sql
select * from T limit 10, 5
```

```sql
select * from T limit 5
```

--------------------------------

### Install Groovy using MacPorts

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-getting-started.adoc

If you are using macOS and have MacPorts installed, you can install Groovy with a simple command.

```shell
sudo port install groovy
```

--------------------------------

### Install Module with Grape CLI

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/grape.adoc

Use the `grape install` command to install a specified Groovy module or Maven artifact into the local Grape cache. If a version is not provided, the most recent version will be installed.

```bash
grape install [-hv] <group> <module> [<version>] [<classifier>]
```

--------------------------------

### Install Groovy using Homebrew

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-getting-started.adoc

For macOS users with Homebrew installed, Groovy can be installed using the brew command.

```shell
brew install groovy
```

--------------------------------

### Write and Print File Size (Groovy)

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_design-pattern-loan-my-resource.adoc

Demonstrates writing to a file and then printing its size using Groovy's built-in file handling, which implicitly uses the Loan my Resource pattern.

```groovy
def file = new File("test.txt")
file.withWriter {
    it.writeLine("Hello world!")
}
println "File size: ${file.length()}"
```

--------------------------------

### Build Runnable Local Installation

Source: https://github.com/apache/groovy/blob/master/README.adoc

Generate a runnable local installation of Groovy with your changes applied. The installation will be located under subprojects/groovy-binary/build/install.

```bash
./gradlew :groovy-binary:installGroovy
```

--------------------------------

### SQL Logging Output with Batching

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-sql/src/spec/doc/sql-userguide.adoc

Example output demonstrating the detailed SQL statements logged when batching is enabled, showing how data is grouped and executed.

```text
INFO  org.codehaus.groovy.sql.GroovySql - Executing batch of 100 statements
INFO  org.codehaus.groovy.sql.GroovySql - INSERT INTO USERS (firstname, lastname) VALUES ('John', 'Doe')
INFO  org.codehaus.groovy.sql.GroovySql - INSERT INTO USERS (firstname, lastname) VALUES ('Jane', 'Smith')
...
```

--------------------------------

### GINQ Grouping Example 03

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_03,indent=0]
```

--------------------------------

### Equivalent Code for Releasing Resources (Immediate Optional)

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

This code is equivalent to the previous example, showing that the `immediate` parameter is optional when releasing resources and waiting for tasks.

```groovy
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_tips_10,indent=0]
```

--------------------------------

### GINQ Grouping Example 15

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_15,indent=0]
```

--------------------------------

### Build Documentation

Source: https://github.com/apache/groovy/blob/master/README.adoc

Compile the Groovy Language Documentation using this command.

```bash
./gradlew asciidoc
```

--------------------------------

### GINQ Grouping Example 14

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_14,indent=0]
```

--------------------------------

### Basic Groovy Servlet Server Setup

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-servlet/src/spec/doc/servlet-userguide.adoc

Sets up an embedded Jetty server to handle Groovy scripts. Ensure the base resource path is correctly configured.

```groovy
import org.eclipse.jetty.ee9.servlet.ServletContextHandler

var server = new Server(8080)
var handler = new ServletContextHandler(server, '/', ServletContextHandler.SESSIONS)
handler.baseResourceAsString = 'path_to_servlet_base'
handler.addServlet(GroovyServlet, '*.groovy')
server.start()
server.join()
```

--------------------------------

### Build and Run Unit Tests

Source: https://github.com/apache/groovy/blob/master/README.adoc

Execute this command to build the project and run all unit tests.

```bash
./gradlew test
```

--------------------------------

### GINQ Grouping Example 12

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_12,indent=0]
```

--------------------------------

### GINQ Grouping Example 11

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_11,indent=0]
```

--------------------------------

### Creating a Stored Procedure with Input and Output Parameters

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-sql/src/spec/doc/sql-userguide.adoc

Example of creating a stored procedure with both input and output parameters.

```groovy
def sql = Sql.newInstance(url, user, password, driver)

sql.execute '''
CREATE PROCEDURE concat_name(IN firstname VARCHAR(100), IN lastname VARCHAR(100), OUT fullname VARCHAR(200))
  SET fullname = firstname || ' ' || lastname
'''
```

--------------------------------

### Basic Compiler Configuration Setup

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-domain-specific-languages.adoc

This code demonstrates the basic structure for creating and configuring a Groovy compiler configuration, including adding compilation customizers and using it with GroovyShell.

```groovy
import org.codehaus.groovy.control.CompilerConfiguration

// create a configuration
def config = new CompilerConfiguration()
// tweak the configuration
config.addCompilationCustomizers(...)
// run your script
def shell = new GroovyShell(config)
shell.evaluate(script)
```

--------------------------------

### GINQ Grouping Example 04

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_04,indent=0]
```

--------------------------------

### Use a Configuration Script

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/tools-groovy.adoc

Provide a configuration script using the `--configscript` option for advanced compiler configuration.

```bash
groovy --configscript config/config.groovy src/Person.groovy
```

--------------------------------

### GINQ Grouping Example 05

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

A GINQ grouping example.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_grouping_05,indent=0]
```

--------------------------------

### Geb Browser Initialization and Navigation

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-testing-guide.adoc

Demonstrates initializing a Geb Browser instance with a Firefox driver and base URL, then navigating to a specific page and interacting with elements.

```groovy
import geb.Browser
import org.openqa.selenium.firefox.FirefoxDriver

def browser = new Browser(driver: new FirefoxDriver(), baseUrl: 'http://myhost:8080/myapp')  // <1>
browser.drive {
    go "/login"                        // <2>

    $("#username").text = 'John'       // <3>
```

--------------------------------

### Groovy Command Chain Examples

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-domain-specific-languages.adoc

Illustrates various forms of Groovy's command chain syntax, including chaining with arguments, closures, and named arguments.

```groovy
def result = "hello" world "groovy"
assert result == "hello".world("groovy")
```

```groovy
def result = "hello" world("groovy", "cool")
assert result == "hello".world("groovy", "cool")
```

```groovy
def result = "hello" world { "groovy" }
assert result == "hello".world { "groovy" }
```

```groovy
def result = "hello" world(arg1: "groovy", arg2: "cool") { "closure" }
assert result == "hello".world(arg1: "groovy", arg2: "cool") { "closure" }
```

```groovy
def result = "hello" world
assert result == "hello".world()
```

--------------------------------

### Instantiating JmxBuilder

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-jmx/src/spec/doc/jmx.adoc

Shows the basic setup for using JmxBuilder, a Groovy DSL for the JMX API. Ensure the JmxBuilder jar is on the classpath.

```groovy
include::../test/JmxTest.groovy[tags=instantiating_jmxbuilder,indent=0]
```

--------------------------------

### Right Outer Join Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

An example of a right outer join in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_joining_05,indent=0]
```

--------------------------------

### Launch Jetty Server with @Grab

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/grape.adoc

Demonstrates launching a Jetty server to serve Groovy templates using @Grab annotations for dependencies. Grape will download and cache Jetty and its dependencies.

```groovy
@Grab('org.eclipse.jetty.aggregate:jetty-server:8.1.19.v20160209')
@Grab('org.eclipse.jetty.aggregate:jetty-servlet:8.1.19.v20160209')
@Grab('javax.servlet:javax.servlet-api:3.0.1')
import org.eclipse.jetty.server.Server
import org.eclipse.jetty.servlet.ServletContextHandler
import groovy.servlet.TemplateServlet

def runServer(duration) {
    def server = new Server(8080)
    def context = new ServletContextHandler(server, "/", ServletContextHandler.SESSIONS)
    context.resourceBase = "."
    context.addServlet(TemplateServlet, "*.gsp")
    server.start()
    sleep duration
    server.stop()
}

runServer(10000)
```

--------------------------------

### Left Outer Join Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

An example of a left outer join in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_joining_04,indent=0]
```

--------------------------------

### Collaborator Classes Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-testing-guide.adoc

Defines example collaborator classes used in mocking scenarios.

```groovy
class Collaborator {
    def doSomething() { "did something" }
}

class AnotherCollaborator {
    def doSomethingElse(String msg) { "did something else with: ${msg}" }
}
```

--------------------------------

### Abstract Factory Usage (Groovy)

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_design-pattern-abstract-factory.adoc

Demonstrates how to use the abstract factory to create and start a game. The first line configures which family of concrete game classes will be used.

```groovy
def gameFactory = new TwoUpGameFactory()
// def gameFactory = new GuessingGameFactory()

GameFactory.factory = gameFactory

def game = GameFactory.factory.createGame()
game.start()
```

--------------------------------

### Inner Join Example with Alias

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-ginq/src/spec/doc/ginq-userguide.adoc

An example of an inner join with table aliases in GINQ.

```sql
include::../test/org/apache/groovy/ginq/GinqTest.groovy[tags=ginq_joining_02,indent=0]
```

--------------------------------

### AutoExternalize Equivalent Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-metaprogramming.adoc

Presents the equivalent implementation of the @AutoExternalize example without the AST transformation.

```groovy
include::../test/CloningASTTransformsTest.groovy[tags=example_autoext_equiv,indent=0]
```

--------------------------------

### Basic glue Usage

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-swing/src/spec/doc/_swing-builder-widgets.adoc

Demonstrates the basic usage of the glue widget.

```groovy
swing.glue()
```

--------------------------------

### Format String Checker Introduction Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-typecheckers/src/spec/doc/typecheckers.adoc

An introductory example for the FormatStringChecker, demonstrating the creation of a formatted string with multiple terms using format specifiers like %f, %X, and %B. This example checks the correctness of the format string and arguments.

```groovy
include::../test/FormatStringCheckerTest.groovy[tags=intro_example,indent=0]
```

--------------------------------

### Configuring a List of Elements (Usage)

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-domain-specific-languages.adoc

Demonstrates how to call the configureList method with a closure.

```groovy
def list = [1, 2, 3]
configureList(list) {
    // delegate is the element of the list
    println "Element: " + it
}
```

--------------------------------

### Groovy List Creation and Heterogeneous Types

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-syntax.adoc

Demonstrates creating a Groovy list and shows how it can contain elements of different data types.

```groovy
def list = [1, "hello", true]
assert list.size() == 3
assert list[0] == 1
assert list[1] == "hello"
assert list[2] == true
```

--------------------------------

### Groovy Class Instantiation

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-object-orientation.adoc

Demonstrates how to instantiate a Groovy class using the 'new' keyword. This is similar to Java but benefits from Groovy's concise syntax.

```groovy
def person = new Person()
person.name = "World"
println person.greet()
```

--------------------------------

### User Code for @TimedInterrupt Fibonacci Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-metaprogramming.adoc

An example of a potentially long-running user script (Fibonacci calculation) that can be managed by the @TimedInterrupt transformation.

```groovy
include::../test/SaferScriptingASTTransformsTest.groovy[tags=timedinterrupt_fib,indent=0]
```

--------------------------------

### GroovyScriptEngine Initialization and Execution

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/guide-integrating.adoc

Initializes a GroovyScriptEngine to manage scripts from a directory and executes a script that returns a Greeter instance.

```groovy
def engine = new GroovyScriptEngine('src/test-resources/reloading')
def greeter = engine.run('source1.groovy', null)
greeter.sayHello()
```

--------------------------------

### List Installed Modules with Grape CLI

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/grape.adoc

Use the `grape list` command to display all locally installed modules and their versions within the Grape cache.

```bash
grape list
```

--------------------------------

### Using a Stored Procedure with Input and Output Parameters

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-sql/src/spec/doc/sql-userguide.adoc

Example of calling a stored procedure with input and output parameters, specifying the output type.

```groovy
def sql = Sql.newInstance(url, user, password, driver)

def result = sql.call("call concat_name(?, ?, ?)", ["John", "Smith", Sql.VARCHAR])
println result
```

--------------------------------

### Type Checking Regex Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-typecheckers/src/spec/doc/typecheckers.adoc

Demonstrates how to type check a regular expression example using the RegexChecker. This ensures that the regex is valid and will not fail at runtime.

```groovy
include::../test/RegexCheckerTest.groovy[tags=checked_example,indent=0]
```

--------------------------------

### More Involved SwingBuilder Example with Code Reuse

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-swing/src/spec/doc/_swing-builder.adoc

Shows a more complex SwingBuilder example that utilizes closures for code re-use, allowing for modular GUI construction.

```groovy
def frame = swing.Frame("More Involved Example") {
    def panel = swing.Panel() {
        label = swing.Label("A label")
        button = swing.Button("Click Me") {
            action {
                println "Button clicked!"
            }
        }
    }
    pack()
    visible true
}
```

--------------------------------

### Create and Update an Agent

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-concurrent-actors.adoc

Demonstrates creating an Agent with an initial value and updating it using send. Asserts the final value after all updates are processed.

```groovy
import groovy.concurrent.Agent

def counter = Agent.create(0)
counter.send { it + 1 }
counter.send { it + 1 }
counter.send { it + 1 }

assert await(counter.getAsync()) == 3
```

--------------------------------

### Basic popupMenu Usage

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-swing/src/spec/doc/_swing-builder-widgets.adoc

Demonstrates the basic instantiation of a JPopupMenu using the Swing Builder.

```groovy
swing.popupMenu()
```

--------------------------------

### Parallel Transformation Examples

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/core-parallel-collections.adoc

Provides examples of parallel transformation methods. `collectParallel` transforms each element, while `collectManyParallel` transforms and flattens the results into a single collection.

```groovy
def names = people.collectParallel { it.name }
def allTags = articles.collectManyParallel { it.tags }
```

--------------------------------

### Groovy Classes for Delegation Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_design-pattern-delegation.adoc

These are the example classes used to demonstrate the delegation pattern. 'Person' is the class that will delegate, and 'Lender' is the object providing the methods.

```groovy
class Person {
    String name
}

class Lender {
    def borrowAmount() {
        return 1000
    }

    def lendMoney() {
        return "Money lent"
    }

    def getLoanDetails() {
        return "Loan details"
    }
}
```

--------------------------------

### Simple SwingBuilder Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-swing/src/spec/doc/_swing-builder.adoc

Demonstrates basic usage of SwingBuilder to create a simple GUI hierarchy. This approach is more concise than traditional Swing code.

```groovy
def frame = swing.Frame("Simple Example") {
    label = swing.Label("Hello, SwingBuilder!")
    pack()
    visible true
}
```

--------------------------------

### Invalid Group Count Error Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-typecheckers/src/spec/doc/typecheckers.adoc

Demonstrates a compile-time error detected by RegexChecker when an invalid group count is used in a regex. This example shows how to trigger and identify such errors.

```groovy
include::../test/RegexCheckerTest.groovy[tags=invalid_group_count,indent=0]
```

```groovy
include::../test/RegexCheckerTest.groovy[tags=invalid_group_count_message,indent=0]
```

--------------------------------

### Groovy Monoid Introduction Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_design-pattern-monoid.adoc

Illustrates the basic structure for integer sum, product, and string concatenation, highlighting similarities before refactoring.

```groovy
def sum = { nums ->
    def total = 0
    for (num in nums) {
        total += num
    }
    total
}

def product = { nums ->
    def total = 1
    for (num in nums) {
        total *= num
    }
    total
}

def concat = { strs ->
    def result = ''
    for (str in strs) {
        result += str
    }
    result
}
```

--------------------------------

### Groovy Iterator Example

Source: https://github.com/apache/groovy/blob/master/src/spec/doc/_design-pattern-iterator.adoc

Demonstrates the use of the 'each' closure operator and 'for..in' loop for iterating over collections and maps. This example showcases iterating through numbers, months, and colors.

```groovy
def numbers = [1, 2, 3, 4]
def months = [May: 31, Mar: 31, Apr: 30]
def colors = [java.awt.Color.BLACK, java.awt.Color.WHITE]

numbers.each { println it }
months.each { key, value -> println "${key}=${value}" }
colors.each { println it }
```

--------------------------------

### Manually add a signing key to the keyring

Source: https://github.com/apache/groovy/blob/master/CONTRIBUTING.md

This command sequence demonstrates how to manually fetch a specific key from a keyserver and append it to the Gradle keyring. Use this only when necessary, as Gradle's export-keys is preferred.

```bash
gpg --keyserver hkps://keyserver.ubuntu.com --recv-keys <KEY_ID>
gpg --export --armor <KEY_ID> >> gradle/verification-keyring.keys
```

--------------------------------

### HTML Template Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-templates/src/spec/doc/_markup-template-engine.adoc

Demonstrates generating HTML code, including doctype, tags, and attributes, using the template engine.

```groovy
include::../test/MarkupTemplateEngineSpecTest.groovy[tags=example2_template,indent=0]
```

--------------------------------

### Unclosed Group Error Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-typecheckers/src/spec/doc/typecheckers.adoc

Shows a compile-time error detected by RegexChecker when a group in a regular expression is not properly closed. This example includes the problematic code and the corresponding error message.

```groovy
include::../test/RegexCheckerTest.groovy[tags=unclosed_group,indent=0]
```

```groovy
include::../test/RegexCheckerTest.groovy[tags=unclosed_group_message,indent=0]
```

--------------------------------

### Customizing Groovy Shell Documentation Paths

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-groovysh/src/spec/doc/groovysh.adoc

Example of configuring custom documentation paths in the ~/.groovy/groovysh_init.groovy file.

```groovy
CONSOLE_OPTIONS.docs.groovy='https://groovy-lang.org/documentation.html'
CONSOLE_OPTIONS.docs.'org/jline/.*'='https://www.javadoc.io/doc/org.jline/jline/latest/'
```

```jshell
groovy> /doc groovy
groovy> /doc org.jline.terminal.Terminal
```

--------------------------------

### Basic GET Request with Query Parameters

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-http-builder/src/spec/doc/http-builder.adoc

Demonstrates a basic GET request with query parameters encoded using RFC 3986 percent-encoding. Spaces in keys and values become %20.

```groovy
def client = HttpBuilder.http('https://example.com/')
client.query(page: 1, size: 10)
client.get('/api/items') {
    assert status == 200
    println text
}
```

--------------------------------

### Basic vstrut Usage

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-swing/src/spec/doc/_swing-builder-widgets.adoc

Demonstrates the most basic usage of the `vstrut` widget. No specific setup or imports are required beyond the SwingBuilder instance.

```groovy
swing.vstrut()
```

--------------------------------

### Connect to HSQLDB with DataSource

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-sql/src/spec/doc/sql-userguide.adoc

Connect to an HSQLDB database using an existing DataSource. This example uses the DataSource provided by the HSQLDB driver jar.

```groovy
def ds = new org.hsqldb.jdbc.JDBCDataSource()
ds.setDatabase('jdbc:hsqldb:mem:yourdb')
ds.setUser('sa')
ds.setPassword('_yourPassword_')
def db = new Sql(ds)
```

--------------------------------

### Valid Format String Example

Source: https://github.com/apache/groovy/blob/master/subprojects/groovy-typecheckers/src/spec/doc/typecheckers.adoc

Demonstrates correct usage of format string methods with type checking enabled. This example ensures that the format string and its arguments are compatible, preventing runtime errors.

```groovy
def name = "World"
def message = "Hello %s".format(name)
println message
```