content: package org.apache.lucene.search;
  
  /**
   * 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.io.IOException;
  
  import org.apache.lucene.index.IndexReader;
  import org.apache.lucene.index.Term;
  import org.apache.lucene.util.ToStringUtils;
  
  /** A Query that matches documents containing terms with a specified prefix. A PrefixQuery
   * is built by QueryParser for input like <code>app*</code>.
   *
   * <p>This query uses the {@link
   * MultiTermQuery#CONSTANT_SCORE_AUTO_REWRITE_DEFAULT}
   * rewrite method. */
  public class PrefixQuery extends MultiTermQuery {
    private Term prefix;
  
    /** Constructs a query for terms starting with <code>prefix</code>. */
    public PrefixQuery(Term prefix) {
      this.prefix = prefix;
    }
  
    /** Returns the prefix of this query. */
    public Term getPrefix() { return prefix; }
    
    @Override
    protected FilteredTermEnum getEnum(IndexReader reader) throws IOException {
      return new PrefixTermEnum(reader, prefix);
    }
  
    /** Prints a user-readable version of this query. */
    @Override
    public String toString(String field) {
      StringBuilder buffer = new StringBuilder();
      if (!prefix.field().equals(field)) {
        buffer.append(prefix.field());
        buffer.append(":");
      }
      buffer.append(prefix.text());
      buffer.append('*');
      buffer.append(ToStringUtils.boost(getBoost()));
      return buffer.toString();
    }
  
    @Override
    public int hashCode() {
      final int prime = 31;
      int result = super.hashCode();
      result = prime * result + ((prefix == null) ? 0 : prefix.hashCode());
      return result;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj)
        return true;
      if (!super.equals(obj))
        return false;
      if (getClass() != obj.getClass())
        return false;
      PrefixQuery other = (PrefixQuery) obj;
      if (prefix == null) {
        if (other.prefix != null)
          return false;
      } else if (!prefix.equals(other.prefix))
        return false;
      return true;
    }
  
  }
  