lucene/highlighter/src/java/org/apache/lucene/search/highlight/SimpleHTMLFormatter.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.lucene.search.highlight;

/**
 * Simple {@link Formatter} implementation to highlight terms with a pre and
 * post tag.
 */
public class SimpleHTMLFormatter implements Formatter {
  
  private static final String DEFAULT_PRE_TAG = "<B>";
  private static final String DEFAULT_POST_TAG = "</B>";
  
  private String preTag;
  private String postTag;

  public SimpleHTMLFormatter(String preTag, String postTag) {
    this.preTag = preTag;
    this.postTag = postTag;
  }

  /** Default constructor uses HTML: &lt;B&gt; tags to markup terms. */
  public SimpleHTMLFormatter() {
    this(DEFAULT_PRE_TAG, DEFAULT_POST_TAG);
  }

  /* (non-Javadoc)
   * @see org.apache.lucene.search.highlight.Formatter#highlightTerm(java.lang.String, org.apache.lucene.search.highlight.TokenGroup)
   */
  @Override
  public String highlightTerm(String originalText, TokenGroup tokenGroup) {
    if (tokenGroup.getTotalScore() <= 0) {
      return originalText;
    }

    // Allocate StringBuilder with the right number of characters from the
    // beginning, to avoid char[] allocations in the middle of appends.
    StringBuilder returnBuffer = new StringBuilder(preTag.length() + originalText.length() + postTag.length());
    returnBuffer.append(preTag);
    returnBuffer.append(originalText);
    returnBuffer.append(postTag);
    return returnBuffer.toString();
  }

}