Commafier.java

/*
Copyright 2011-2016 Google 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.google.security.zynamics.zylib.strings;

/**
 * This class can be used to create comma-separated lists of objects.
 */
public final class Commafier {
  private static String DEFAULT_SEPARATOR = ", ";

  private final String m_separator;

  private final StringBuilder sb = new StringBuilder();

  private boolean needsComma = false;

  /**
   * Creates a Commafier object that starts with an empty string.
   */
  public Commafier() {
    m_separator = DEFAULT_SEPARATOR;
  }

  /**
   * Creates a Commafier object that starts with a commafied list that contains the given elements.
   * 
   * @param elements The elements that are commafied into the list.
   */
  public Commafier(final Iterable<? extends Object> elements) {
    this(elements, DEFAULT_SEPARATOR);
  }

  /**
   * Creates a Commafier object that starts with a commafied list that contains the given elements.
   * 
   * @param elements The elements that are commafied into the list.
   */
  public Commafier(final Iterable<? extends Object> elements, final String separator) {
    m_separator = separator;

    for (final Object element : elements) {
      append(element);
    }
  }

  /**
   * Creates a Commafier object that starts with an initial string.
   * 
   * @param initial The initial string.
   */
  public Commafier(final String initial) {
    m_separator = DEFAULT_SEPARATOR;

    sb.append(initial);
  }

  /**
   * Commafies a list of elements and returns the commafied string.
   * 
   * @param elements The elements to commafy.
   * 
   * @return The commafied string.
   */
  public static String commafy(final Iterable<? extends Object> elements) {
    return new Commafier(elements).toString();
  }

  public static String commafy(final Iterable<? extends Object> elements, final String separator) {
    return new Commafier(elements, separator).toString();
  }

  /**
   * Appends a new value to the commafied list.
   * 
   * @param value The value to add to the commafied list.
   */
  public void append(final Object value) {
    if (needsComma) {
      sb.append(m_separator);
    }

    needsComma = true;

    sb.append(value);
  }

  /**
   * Appends a value to the commafied list without prepending a comma.
   * 
   * @param value The value to be appended.
   */
  public void appendUncommafied(final String value) {
    sb.append(value);
  }

  @Override
  public String toString() {
    return sb.toString();
  }
}