Converter.java

package org.springframework.roo.shell;

import java.util.List;

/**
 * Converts between Strings (as displayed by and entered via the shell) and Java
 * objects
 * 
 * @author Ben Alex
 * @param <T> the type being converted to/from
 */
public interface Converter<T> {

  /**
   * Converts from the given String value to type T
   * 
   * @param value the value to convert
   * @param targetType the type being converted to; can't be <code>null</code>
   * @param optionContext a non-<code>null</code> string that customises the
   *            behaviour of this converter for a given {@link CliOption} of a
   *            given {@link CliCommand}; the contents will have special
   *            meaning to this converter (e.g. be a comma-separated list of
   *            keywords known to this converter)
   * @return see above
   * @throws RuntimeException if the given value could not be converted
   */
  T convertFromText(String value, Class<?> targetType, String optionContext);

  /**
   * Populates the given list with the possible completions
   * 
   * @param completions the list to populate; can't be <code>null</code>
   * @param targetType the type of parameter for which a string is being
   *            entered
   * @param existingData what the user has typed so far
   * @param optionContext a non-<code>null</code> string that customises the
   *            behaviour of this converter for a given {@link CliOption} of a
   *            given {@link CliCommand}; the contents will have special
   *            meaning to this converter (e.g. be a comma-separated list of
   *            keywords known to this converter)
   * @param target
   * @return <code>true</code> if all the added completions are complete
   *         values, or <code>false</code> if the user can press TAB to add
   *         further information to some or all of them
   */
  boolean getAllPossibleValues(List<Completion> completions, Class<?> targetType,
      String existingData, String optionContext, MethodTarget target);

  /**
   * Indicates whether this converter supports the given type in the given
   * option context
   * 
   * @param type the type being checked
   * @param optionContext a non-<code>null</code> string that customises the
   *            behaviour of this converter for a given {@link CliOption} of a
   *            given {@link CliCommand}; the contents will have special
   *            meaning to this converter (e.g. be a comma-separated list of
   *            keywords known to this converter)
   * @return see above
   */
  boolean supports(Class<?> type, String optionContext);
}