Groovy example source code file (AutoIndentAction.groovy)

This example Groovy source code file (AutoIndentAction.groovy) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

abstractaction, abstractaction, attributeset, attributeset, autoindentaction, awt, event, gui, simpleattributeset, simpleattributeset, string, string, swing, text

The Groovy AutoIndentAction.groovy source code

/*
 * Copyright 2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package groovy.ui.text

import java.awt.event.ActionEvent
import javax.swing.AbstractAction
import javax.swing.text.AttributeSet
import javax.swing.text.SimpleAttributeSet

class AutoIndentAction extends AbstractAction {
    AttributeSet simpleAttributeSet = new SimpleAttributeSet()

    public void actionPerformed(ActionEvent evt) {
        def inputArea = evt.source
        def rootElement = inputArea.document.defaultRootElement
        def cursorPos = inputArea.getCaretPosition()
        int rowNum = rootElement.getElementIndex(cursorPos)
        def rowElement = rootElement.getElement(rowNum)
        int startOffset = rowElement.getStartOffset()
        int endOffset = rowElement.getEndOffset()
        String rowContent = inputArea.document.getText(startOffset, endOffset - startOffset);
        String contentBeforeCursor = inputArea.document.getText(startOffset, cursorPos - startOffset);
        String whitespaceStr = ''
        def matcher = (rowContent =~ /(?m)^(\s*).*\n$/)
        matcher.each { all, ws ->
            whitespaceStr = ws
        }

        if (contentBeforeCursor ==~ /(\s)*/) {
            whitespaceStr = contentBeforeCursor
        }

        inputArea.document.insertString(cursorPos, '\n' + whitespaceStr, simpleAttributeSet)
    }
}