parquet-column/src/test/java/parquet/column/values/RandomStr.java

/**
 * Copyright 2012 Twitter, 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 parquet.column.values;

import java.util.Random;

/**
 * 
 * @author Aniket Mokashi
 *
 */
public class RandomStr {
  private final char[] alphanumeric=alphanumeric();
  private final Random rand;

  public RandomStr(){this(null);}

  public RandomStr(Random rand){
    this.rand=(rand!=null) ? rand : new Random();
  }

  public String get(int len){
    StringBuffer out=new StringBuffer();

    while(out.length() < len){
      int idx=Math.abs(( rand.nextInt() % alphanumeric.length ));
      out.append(alphanumeric[idx]);
    }
    return out.toString();
  }

  // create alphanumeric char array
  private char[] alphanumeric(){
    StringBuffer buf=new StringBuffer(128);
    for(int i=48; i<= 57;i++)buf.append((char)i); // 0-9
    for(int i=65; i<= 90;i++)buf.append((char)i); // A-Z
    for(int i=97; i<=122;i++)buf.append((char)i); // a-z
    return buf.toString().toCharArray();
  }
}