spangradientformatter.java

lucene2.2.0版本

package org.apache.lucene.search.highlight;
/**
 * 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.
 */

/**
 * Formats text with different color intensity depending on the score of the
 * term using the span tag.  GradientFormatter uses a bgcolor argument to the font tag which
 * doesn't work in Mozilla, thus this class.
 *
 * @see GradientFormatter
 * @author David Spencer [e-mail]
 */

public class SpanGradientFormatter
	extends GradientFormatter
{
	public SpanGradientFormatter(float maxScore, String minForegroundColor,
            String maxForegroundColor, String minBackgroundColor,
            String maxBackgroundColor)
    {
		super( maxScore, minForegroundColor,
			   maxForegroundColor, minBackgroundColor,
			   maxBackgroundColor);
	}
	

	
	public String highlightTerm(String originalText, TokenGroup tokenGroup)
    {
        if (tokenGroup.getTotalScore() == 0)
            return originalText;
        float score = tokenGroup.getTotalScore();
        if (score == 0)
        {
            return originalText;
        }

		// try to size sb correctly
        StringBuffer sb = new StringBuffer( originalText.length() + EXTRA);
		
		sb.append("<span style=\""); 
		if (highlightForeground) 
		{
			sb.append("color: "); 
			sb.append(getForegroundColorString(score)); 
			sb.append("; "); 
		}
		if (highlightBackground)
		{
			sb.append("background: ");
			sb.append(getBackgroundColorString(score));
			sb.append("; ");
		}
		sb.append("\">");
		sb.append(originalText);
		sb.append("</span>");
        return sb.toString();
    }

	// guess how much extra text we'll add to the text we're highlighting to try to avoid a  StringBuffer resize
	private static final String TEMPLATE = "<span style=\"background: #EEEEEE; color: #000000;\">...</span>";
	private static final int EXTRA = TEMPLATE.length();	
}