/**
 * Copyright (c) 2008, SnakeYAML
 *
 * 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 org.yaml.snakeyaml.parser;

import org.yaml.snakeyaml.events.Event;

/**
 * This interface represents an input stream of {@link Event Events}.
 * <p>
 * The parser and the scanner form together the 'Parse' step in the loading process (see chapter 3.1
 * of the <a href="http://yaml.org/spec/1.1/">YAML Specification</a>).
 * </p>
 *
 * @see org.yaml.snakeyaml.events.Event
 */
public interface Parser {

  /**
   * Check if the next event is one of the given type.
   *
   * @param choice Event ID.
   * @return <code>true</code> if the next event can be assigned to a variable of the given type.
   *         Returns <code>false</code> if no more events are available.
   * @throws ParserException Thrown in case of malformed input.
   */
  boolean checkEvent(Event.ID choice);

  /**
   * Return the next event, but do not delete it from the stream.
   *
   * @return The event that will be returned on the next call to {@link #getEvent}
   * @throws ParserException Thrown in case of malformed input.
   */
  Event peekEvent();

  /**
   * Returns the next event.
   * <p>
   * The event will be removed from the stream.
   * </p>
   *
   * @return the next parsed event
   * @throws ParserException Thrown in case of malformed input.
   */
  Event getEvent();
}
