UnindentAction.java

/*
 * Copyright 2008 Ayman Al-Sairafi ayman.alsairafi@gmail.com
 * 
 * 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 jsyntaxpane.actions;

import java.awt.event.ActionEvent;
import javax.swing.text.JTextComponent;
import javax.swing.text.PlainDocument;
import javax.swing.text.TextAction;
import jsyntaxpane.util.Configuration;

/**
 * This is usually mapped to Shift-TAB to unindent the selection.  The
 * current line, or the selected lines are un-indented by the tabstop of the
 * document.
 */
public class UnindentAction extends TextAction implements SyntaxAction {

    public UnindentAction() {
        super("UNINDENT");
    }

    public void actionPerformed(ActionEvent e) {
        JTextComponent target = getTextComponent(e);
        Integer tabStop = (Integer) target.getDocument().getProperty(PlainDocument.tabSizeAttribute);
        String indent = ActionUtils.SPACES.substring(0, tabStop);
        if (target != null) {
            String[] lines = ActionUtils.getSelectedLines(target);
            int start = target.getSelectionStart();
            StringBuilder sb = new StringBuilder();
            for (String line : lines) {
                if (line.startsWith(indent)) {
                    sb.append(line.substring(indent.length()));
                } else if (line.startsWith("\t")) {
                    sb.append(line.substring(1));
                } else {
                    sb.append(line);
                }
                sb.append('\n');
            }
            target.replaceSelection(sb.toString());
            target.select(start, start + sb.length());
        }
    }

    public void config(Configuration config, String prefix, String name) {
    }

    public TextAction getAction(String key) {
        return this;
    }
}