library/src/main/java/com/datatorrent/lib/streamquery/condition/LikeCondition.java

/*
 * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved.
 *
 * 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 com.datatorrent.lib.streamquery.condition;

import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.validation.constraints.NotNull;


/**
 * An implementation of condition class to filter rows for which given column name value matches given regular expression. <br>
 *<p>
 *<b> Properties : </b> <br>
 *<b> column : < /b> Column to be matched with regular expression. <br>
 *<b> pattern : </b> Regular expression pattern.<br>
 * @displayName: Like Condition
 * @category: streamquery/condition
 * @tag: sql, like condition, regular expression
 * @since 0.3.4
 */
public class LikeCondition extends Condition
{
  /**
   * Column to be matched with regular expression.
   */
  @NotNull
  private String column;
  
  /**
   * Regular expression pattern.
   */
  @NotNull
  private Pattern pattern;
  
  /**
   * @param column Column to be matched with regular expression, must be non-null.
   * @param pattern Regular expression pattern, must be non-null.
   */
  public LikeCondition(@NotNull String column,@NotNull String pattern) {
    setColumn(column);
    setPattern(pattern);
  }
  
  /**
   * For valid row column value string must match regular expression.  
   * @return row valid status.
   */
  @Override
  public boolean isValidRow(Map<String, Object> row)
  {
    if (!row.containsKey(column)) return false;
    Matcher match = pattern.matcher((CharSequence) row.get(column));
    if (!match.find()) return false;
    return true;
  }

  /**
   * Must not be called. 
   */
  @Override
  public boolean isValidJoin(Map<String, Object> row1, Map<String, Object> row2)
  {
    assert(false);
    return false;
  }

  public String getColumn()
  {
    return column;
  }

  public void setColumn(String column)
  {
    this.column = column;
  }

  public void setPattern(String pattern)
  {
    this.pattern = Pattern.compile(pattern);
  }

}