com.google.gwt.logging.client.HasWidgetsLogHandler.java Source code

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Here is the source code for com.google.gwt.logging.client.HasWidgetsLogHandler.java

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/*
 * Copyright 2010 Google Inc.
 * 
 * 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 com.google.gwt.logging.client;

import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HasWidgets;
import com.google.gwt.user.client.ui.Label;

import java.util.logging.Formatter;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogRecord;

/**
 * A handler which can log to any widget which extends the HasWidgets interface.
 * This allows users to log to anywhere they would like in their UI - see the
 * LogConfiguration class for an example. Note that the widget passed in must
 * handle multiple calls to widget.add(widget) gracefully.
 */
public class HasWidgetsLogHandler extends Handler {

    private HasWidgets widgetContainer;

    public HasWidgetsLogHandler(HasWidgets container) {
        this.widgetContainer = container;
        setFormatter(new HtmlLogFormatter(true));
        setLevel(Level.ALL);
    }

    public void clear() {
        widgetContainer.clear();
    }

    @Override
    public void close() {
        // Do nothing
    }

    @Override
    public void flush() {
        // Do nothing
    }

    @Override
    public void publish(LogRecord record) {
        if (!isLoggable(record)) {
            return;
        }
        Formatter formatter = getFormatter();
        String msg = formatter.format(record);
        // We want to make sure that unescaped messages are not output as HTML to
        // the window and the HtmlLogFormatter ensures this. If you want to write a
        // new formatter, subclass HtmlLogFormatter and override the getHtmlPrefix
        // and getHtmlSuffix methods.
        if (formatter instanceof HtmlLogFormatter) {
            widgetContainer.add(new HTML(msg));
        } else {
            widgetContainer.add(new Label(msg));
        }
    }
}