CsvColumnSource.java

/*
 * Copyright (C) 2012 Google 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 interactivespaces.util.data;

/**
 * A {@link ColumnSource} for CSV data.
 *
 * @author Keith M. Hughes
 */
public class CsvColumnSource implements ColumnSource {

  /**
   * The current line being processed.
   */
  private String line;

  /**
   * Current position in the line.
   */
  private int pos = 0;

  /**
   * Buffer for building up the data.
   */
  private StringBuilder builder = new StringBuilder();

  /**
   * Set the line to be processed.
   *
   * @param line
   *          The line to be processed.
   */
  public void setLine(String line) {
    this.line = line;
    pos = 0;
  }

  @Override
  public String getColumn() {
    builder.setLength(0);

    char c = line.charAt(pos);
    boolean quoted = c == '"';
    if (quoted)
      pos++;
    for (; pos < line.length(); pos++) {
      c = line.charAt(pos);
      if (c == ',' && !quoted) {
        break;
      }

      if (c == '"') {
        if (quoted) {
          // We're quoted, either a double quote, or we are
          // ending. Check.
          int npos = pos + 1;
          if (npos < line.length()) {
            c = line.charAt(npos);
            if (c == '"') {
              builder.append(c);
              pos = npos;
              continue;
            } else {
              // Not a quoted quote, so must be at end of
              // quote

              // skip over quote
              pos++;

              break;
            }
          } else {
            // No next character, so is final quote
            break;
          }
        }
      }

      builder.append(c);
    }

    // Either there are more characters in line and we reached an end
    // character, so
    // need to move on, or this doesn't matter as we are at the end of
    // the string.
    pos++;

    return new String(builder.toString());
  }

}