HogeWindow.kt

import com.intellij.openapi.project.Project
import com.intellij.openapi.wm.ToolWindow
import com.intellij.openapi.wm.ToolWindowFactory
import java.awt.*
import javax.swing.JComponent
import javax.swing.JLabel
import javax.swing.JPanel
import javax.swing.JTextField

class HogeWindow: ToolWindowFactory {
    override fun createToolWindowContent(project: Project, toolWindow: ToolWindow) {
        val layout = GridBagLayout()
        val component = toolWindow.component.jPanel(layout) {
            jTextField {
                preferredSize = Dimension(150, 30)
                val cs = GridBagConstraints().apply {
                    gridx = 1
                    gridy = 0
                }
                layout.setConstraints(this, cs)
            }
            jLabel("HogeHoge") {
                val cs = GridBagConstraints().apply {
                    gridx = 0
                    gridy = 0
                }
                layout.setConstraints(this, cs)
            }
        }
    }

    fun <T: JComponent> T.jPanel(
            layoutManager: LayoutManager = GridLayout(),
            isDoubleBuffered: Boolean = false,
            initializer: (JPanel.() -> Unit)? = null): T {
        val panel = JPanel(layoutManager, isDoubleBuffered)
        initializer?.invoke(panel)
        add(panel)
        return this
    }

    fun <T: JComponent> T.jLabel(text: String, initializer: (JLabel.() -> Unit)? = null): T {
        val label = JLabel(text)
        initializer?.invoke(label)
        add(label)
        return this
    }

    fun <T: JComponent> T.jTextField(initializer: (JTextField.() -> Unit)? = null): T {
        val textField = JTextField()
        initializer?.invoke(textField)
        add(textField)
        return this
    }
}