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Lucene example source code file (JavaUtilRegexCapabilities.java)

This example Lucene source code file (JavaUtilRegexCapabilities.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

flag_canon_eq, flag_canon_eq, flag_case_insensitive, flag_case_insensitive, flag_comments, flag_multiline, flag_unicode_case, flag_unix_lines, javautilregexcapabilities, javautilregexcapabilities, override, override, regex, regexcapabilities, string

The Lucene JavaUtilRegexCapabilities.java source code

package org.apache.lucene.search.regex;

/**
 * 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.
 */

import java.util.regex.Pattern;

/**
 * An implementation tying Java's built-in java.util.regex to RegexQuery.
 *
 * Note that because this implementation currently only returns null from
 * {@link #prefix} that queries using this implementation will enumerate and
 * attempt to {@link #match} each term for the specified field in the index.
 */
public class JavaUtilRegexCapabilities implements RegexCapabilities {
  private Pattern pattern;
  private int flags = 0;
  
  // Define the optional flags from Pattern that can be used.
  // Do this here to keep Pattern contained within this class.
  
  public static final int FLAG_CANON_EQ = Pattern.CANON_EQ;
  public static final int FLAG_CASE_INSENSITIVE = Pattern.CASE_INSENSITIVE;
  public static final int FLAG_COMMENTS = Pattern.COMMENTS;
  public static final int FLAG_DOTALL = Pattern.DOTALL;
  public static final int FLAG_LITERAL = Pattern.LITERAL;
  public static final int FLAG_MULTILINE = Pattern.MULTILINE;
  public static final int FLAG_UNICODE_CASE = Pattern.UNICODE_CASE;
  public static final int FLAG_UNIX_LINES = Pattern.UNIX_LINES;
  
  /**
   * Default constructor that uses java.util.regex.Pattern 
   * with its default flags.
   */
  public JavaUtilRegexCapabilities()  {
    this.flags = 0;
  }
  
  /**
   * Constructor that allows for the modification of the flags that
   * the java.util.regex.Pattern will use to compile the regular expression.
   * This gives the user the ability to fine-tune how the regular expression 
   * to match the functionality that they need. 
   * The {@link java.util.regex.Pattern Pattern} class supports specifying 
   * these fields via the regular expression text itself, but this gives the caller
   * another option to modify the behavior. Useful in cases where the regular expression text
   * cannot be modified, or if doing so is undesired.
   * 
   * @param flags The flags that are ORed together.
   */
  public JavaUtilRegexCapabilities(int flags) {
    this.flags = flags;
  }
  
  public void compile(String pattern) {
    this.pattern = Pattern.compile(pattern, this.flags);
  }

  public boolean match(String string) {
    return pattern.matcher(string).matches();
  }

  public String prefix() {
    return null;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    final JavaUtilRegexCapabilities that = (JavaUtilRegexCapabilities) o;

    if (pattern != null ? !pattern.equals(that.pattern) : that.pattern != null) return false;

    return true;
  }

  @Override
  public int hashCode() {
    return (pattern != null ? pattern.hashCode() : 0);
  }
}

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