#JMeter Query Syntax

The SwingComponentTreeSelector is a powerful CSS-like selector engine used in the Webswing JMeter Plugin to locate and interact with a specific Swing component in your application. It allows you to target a single UI element using a familiar, web-like syntax for precise test automation.

Important: The selector should be specific enough to match exactly one component. If multiple components match, the first one found will be used.

#Basic Syntax

The selector follows a CSS-like pattern to find one specific component:

ComponentType[attribute="value"]:pseudo-selector

#Components of a Selector

1. Component Type - The Swing component class name (e.g., JButton, JTextField)
2. Attributes - Properties of the component in square brackets
3. Pseudo-selectors - Special selectors starting with : for additional filtering
4. Combinators - Relationship operators between selectors

#Component Types

Target a specific component by its class name:

• JButton - A specific button
• JTextField - A specific text input field
• JLabel - A specific text label
• JTable - A specific table (or table cell)
• JList - A specific list
• JPanel - A specific panel
• JFrame - A specific window/frame
• JMenuItem - A specific menu item
• JCheckBox - A specific checkbox
• JRadioButton - A specific radio button

Examples:

JButton[name="loginBtn"]           # The login button specifically
JTextField[name="username"]        # The username text field
JTable[name="dataTable"]          # The data table

#Attributes

Components have various attributes you can filter by:

#Common Attributes

Attribute	Type	Description	Example
name	String	Component name	[name="submitButton"]
value	String	Component value/text	[value="Save"]
enabled	Boolean	Whether component is enabled	[enabled="true"]
visible	Boolean	Whether component is visible	[visible="true"]
width	Number	Component width in pixels	[width="200"]
height	Number	Component height in pixels	[height="30"]
screenx	Number	X coordinate on screen	[screenx="100"]
screeny	Number	Y coordinate on screen	[screeny="50"]
selected	Boolean	Whether component is selected	[selected="true"]
columnHeader	String	Column header (for table cells)	[columnheader="ID"]
rowNumber	Number	Row index (for table cells)	[rownumber="0"]

Using coordinates (screenx, screeny) or dimensions (width, height) is not recommended unless absolutely necessary, as they may change with UI layout adjustments.

#Attribute Operators

Operator	Description	Example
=	Exact match	[name="button1"]
!=	Not equal	[enabled!="false"]
*=	Contains	[name*="submit"]
^=	Starts with	[name^="btn"]
$=	Ends with	[name$="Button"]
>	Greater than (numbers)	[width>"100"]
<	Less than (numbers)	[height<"50"]
>=	Greater than or equal	[screenx>="0"]
<=	Less than or equal	[screeny<="100"]

#Pseudo-selectors

Pseudo-selectors provide additional filtering capabilities:

#Position-based Selectors

Pseudo-selector	Description	Example
:first-child	First child component	JButton:first-child
:last-child	Last child component	JButton:last-child
:nth-child(n)	The nth child component	JButton:nth-child(2)

#Relationship Selectors

Pseudo-selector	Description	Example
:root	Root components	JFrame:root
:parent	Parent components	JButton:parent
:ancestors	All ancestor components	JButton:ancestors
:descendants	All descendant components	JPanel:descendants
:siblings	All sibling components	JButton:siblings
:next-sibling	Next sibling component	JLabel:next-sibling
:prev-sibling	Previous sibling component	JButton:prev-sibling

#Combinators

Combinators define relationships between elements:

Combinator	Description	Example
(space)	Descendant selector	JPanel JButton
>	Direct child selector	JPanel > JButton
+	Adjacent sibling selector	JLabel + JTextField
~	General sibling selector	JButton ~ JTextField

#Common Usage Examples

#Basic Component Selection

# Find button with specific name
JButton[name="submitBtn"]

# Find text field with specific value
JTextField[value="Enter text here"]

#Table Operations

# Find table cell in specific column
JTable[columnheader="Name"]

# Find table cell with specific value in ID column
JTable[columnheader="ID"][value="12345"]

# Find first row in table
JTable:nth-child(1)

#Complex Selections

# Find enabled submit button in a form panel
JPanel[name="formPanel"] > JButton[name*="submit"]:enabled

# Find text field next to a label
JLabel[value="Username:"] + JTextField

# Find all buttons in a dialog that are visible
JDialog JButton:visible

#Position-based Selections

# First button in the application
JButton:first-child

# Last text field in a panel
JPanel JTextField:last-child

# Third menu item
JMenuItem:nth-child(3)

#State-based Selections

# Visible buttons only
JButton:visible

# Hidden panels
JPanel:hidden

#JMeter Plugin Usage

In the Webswing JMeter Plugin, use these selectors in the Query field:

#Click Action Example

• Action Type: click
• Query: JButton[name="saveButton"]:enabled
• Description: Clicks the enabled save button

#Type Action Example

• Action Type: type
• Query: JTextField[name="username"]
• Input: testuser
• Description: Types "testuser" into the username field

#Check Value Example

• Action Type: checkValue
• Query: JLabel[name="status"]
• Value: Connected
• Description: Verifies the status label shows "Connected"

#Table Interaction Example

• Action Type: click
• Query: JTable[columnheader="Actions"][value="Edit"]
• Description: Clicks the "Edit" button in the Actions column

#Best Practices

#1. Use Specific Selectors

# Good - specific and unlikely to match multiple elements
JButton[name="loginButton"]

# Avoid - too generic, may match many buttons
JButton

#2. Combine Attributes for Precision

# Good - combines type, state, and content
JButton[value="Submit"]:enabled

# Better - adds more specific context
JPanel[name="loginForm"] JButton[value="Submit"]:enabled

#3. Use Structural Relationships

# Find input field after its label
JLabel[value="Email:"] + JTextField

# Find button inside specific dialog
JDialog[name="confirmDialog"] JButton[value="OK"]

#Troubleshooting

#Common Issues

1. No Element Found

   • Check if component names/values are correct
   • Verify the component is visible and enabled
   • Use broader selectors first, then narrow down

2. Multiple Elements Matched

   • Add more specific attributes
   • Use structural relationships (parent/child)

3. Selector Not Working

   • Verify attribute names are correct (case-sensitive)
   • Check for typos in pseudo-selectors
   • Ensure proper quotation marks around values