src/main/java/org/apache/log4j/chainsaw/messages/MessageCenter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.log4j.chainsaw.messages;

import org.apache.log4j.Layout;
import org.apache.log4j.TTCCLayout;
import org.apache.log4j.chainsaw.ChainsawConstants;
import org.apache.log4j.chainsaw.LoggingEventWrapper;
import org.apache.log4j.chainsaw.PopupListener;
import org.apache.log4j.chainsaw.SmallButton;
import org.apache.log4j.chainsaw.icons.ChainsawIcons;
import org.apache.log4j.varia.ListModelAppender;

import javax.swing.*;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.beans.PropertyChangeSupport;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;


/**
 * The MessageCenter is central place for all elements within Chainsaw to
 * notify the user of important information.
 * <p>
 * This class uses log4j itself quite significantly.  All user message
 * are sent to this classes log4j Logger (org.apache.log4j.chainsaw.message.MessageCenter).
 * <p>
 * To register a message with the user, you can use the addMessage(String) style methods on
 * this class, or just as easily, get a handle to this class' logger, and log
 * it as you would normally do.
 * <p>
 * All events to this logger are trapped within a Custom appender (additivity
 * will be switched OFF), which stores the events in a ListModel.
 * <p>
 * You can invoke the setVisible() method to display all the messages
 *
 * @author Paul Smith &lt;psmith@apache.org&gt;
 */
public class MessageCenter {
    private static final MessageCenter instance = new MessageCenter();
    private final Logger logger = LogManager.getLogger();
    private Layout layout = new TTCCLayout();
    private final JList<org.apache.log4j.spi.LoggingEvent> messageList = new JList<>();
    private final ListModelAppender appender = new ListModelAppender();
    private ListCellRenderer listCellRenderer =
        new LayoutListCellRenderer(layout);
    private PropertyChangeSupport propertySupport =
        new PropertyChangeSupport(this);
    private JScrollPane pane = new JScrollPane(messageList);
    private final JToolBar toolbar = new JToolBar();
    private JPopupMenu popupMenu = new JPopupMenu();
    private PopupListener popupListener = new PopupListener(popupMenu);
    private Action clearAction;
    private final JPanel componentPanel = new JPanel(new BorderLayout());

    private MessageCenter() {
        setupActions();
        setupComponentPanel();
        setupListeners();
        setupPopMenu();
        setupToolbar();
    }

    /**
     *
     */
    private void setupPopMenu() {
        popupMenu.add(clearAction);
    }

    /**
     *
     */
    private void setupToolbar() {
        JButton clearButton = new SmallButton(clearAction);
        clearButton.setText(null);
        toolbar.add(clearButton);

        toolbar.setFloatable(false);
    }

    private void setupActions() {
        clearAction =
            new AbstractAction("Clear") {
                public void actionPerformed(ActionEvent e) {
                    appender.clearModel();
                }
            };
        clearAction.putValue(
            Action.SMALL_ICON, new ImageIcon(ChainsawIcons.DELETE));
    }

    private void setupListeners() {
        propertySupport.addPropertyChangeListener(
            "layout",
            evt -> {
                Layout newLayout = (Layout) evt.getNewValue();
                messageList.setCellRenderer(new LayoutListCellRenderer(newLayout));
            });
        messageList.addMouseListener(popupListener);

        appender.getModel().addListDataListener(
            new ListDataListener() {
                public void contentsChanged(ListDataEvent e) {
                    updateActions();
                }

                public void intervalAdded(ListDataEvent e) {
                    updateActions();
                }

                public void intervalRemoved(ListDataEvent e) {
                    updateActions();
                }
            });
    }

    /**
     *
     */
    private void updateActions() {
        clearAction.putValue(
            "enabled",
            (appender.getModel().getSize() > 0) ? Boolean.TRUE : Boolean.FALSE);
    }

    private void setupComponentPanel() {
        messageList.setModel(appender.getModel());
        messageList.setCellRenderer(listCellRenderer);

        componentPanel.add(this.toolbar, BorderLayout.NORTH);
        componentPanel.add(this.pane, BorderLayout.CENTER);
    }

    public final JComponent getGUIComponent() {
        return componentPanel;
    }

    public ListModel<org.apache.log4j.spi.LoggingEvent> getModel() {
        return messageList.getModel();
    }

    public static MessageCenter getInstance() {
        return instance;
    }

    public void addMessage(String message) {
        logger.info(message);
    }


    /**
     * @return Returns the layout used by the MessageCenter.
     */
    public final Layout getLayout() {
        return layout;
    }

    /**
     * @param layout Sets the layout to be used by the MessageCenter .
     */
    public final void setLayout(Layout layout) {
        Layout oldValue = this.layout;
        this.layout = layout;
        propertySupport.firePropertyChange("layout", oldValue, this.layout);
    }

    /**
     * Returns the logger that can be used to log
     * messages to display within the Message Center.
     *
     * @return logger
     */
    public final Logger getLogger() {
        return this.logger;
    }

    /**
     * This class simply renders an event by delegating the effort to a
     * Log4j layout instance.
     *
     * @author Paul Smith &lt;psmith@apache.org&gt;
     */
    private static class LayoutListCellRenderer extends DefaultListCellRenderer {
        private Layout layout;

        /**
         * @param layout
         */
        public LayoutListCellRenderer(Layout layout) {
            super();
            this.layout = layout;
        }

        /* (non-Javadoc)
         * @see javax.swing.ListCellRenderer#getListCellRendererComponent(javax.swing.JList, java.lang.Object, int, boolean, boolean)
         */
        public Component getListCellRendererComponent(
            JList list, Object value, int index, boolean isSelected,
            boolean cellHasFocus) {
            //value = layout.format(((LoggingEventWrapper) value).getLoggingEvent());
            value = ((LoggingEventWrapper) value).getLoggingEvent().m_message;

            Component c =
                super.getListCellRendererComponent(
                    list, value, index, isSelected, cellHasFocus);
            c.setBackground(
                ((index % 2) == 0) ? ChainsawConstants.COLOR_EVEN_ROW_BACKGROUND
                    : ChainsawConstants.COLOR_ODD_ROW_BACKGROUND);

            return c;
        }
    }
}