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    * and other copyright owners as documented in the project's IP log.
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    * available at http://www.eclipse.org/org/documents/edl-v10.php
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  package org.eclipse.jgit.transport;
  
  import java.util.Arrays;
  
  import org.eclipse.jgit.internal.JGitText;
  
  /**
   * A credential requested from a
   * {@link org.eclipse.jgit.transport.CredentialsProvider}.
   *
   * Most users should work with the specialized subclasses:
   * <ul>
   * <li>{@link org.eclipse.jgit.transport.CredentialItem.Username} for
   * usernames</li>
   * <li>{@link org.eclipse.jgit.transport.CredentialItem.Password} for
   * passwords</li>
   * <li>{@link org.eclipse.jgit.transport.CredentialItem.StringType} for other
   * general string information</li>
   * <li>{@link org.eclipse.jgit.transport.CredentialItem.CharArrayType} for other
   * general secret information</li>
   * </ul>
   *
   * This class is not thread-safe. Applications should construct their own
   * instance for each use, as the value is held within the CredentialItem object.
   */
  public abstract class CredentialItem {
  	private final String promptText;
  
  	private final boolean valueSecure;
  
  	/**
  	 * Initialize a prompt.
  	 *
  	 * @param promptText
  	 *            prompt to display to the user alongside of the input field.
  	 *            Should be sufficient text to indicate what to supply for this
  	 *            item.
  	 * @param maskValue
  	 *            true if the value should be masked from displaying during
  	 *            input. This should be true for passwords and other secrets,
  	 *            false for names and other public data.
  	 */
  	public CredentialItem(String promptText, boolean maskValue) {
  		this.promptText = promptText;
  		this.valueSecure = maskValue;
  	}
  
  	/**
  	 * Get prompt to display to the user.
  	 *
  	 * @return prompt to display to the user.
  	 */
  	public String getPromptText() {
  		return promptText;
  	}
  
 	/**
 	 * Whether the value should be masked when entered.
 	 *
 	 * @return true if the value should be masked when entered.
 	 */
 	public boolean isValueSecure() {
 		return valueSecure;
 	}
 
 	/**
 	 * Clear the stored value, destroying it as much as possible.
 	 */
 	public abstract void clear();
 
 	/**
 	 * An item whose value is stored as a string.
 	 *
 	 * When working with secret data, consider {@link CharArrayType} instead, as
 	 * the internal members of the array can be cleared, reducing the chances
 	 * that the password is left in memory after authentication is completed.
 	 */
 	public static class StringType extends CredentialItem {
 		private String value;
 
 		/**
 		 * Initialize a prompt for a single string.
 		 *
 		 * @param promptText
 		 *            prompt to display to the user alongside of the input
 		 *            field. Should be sufficient text to indicate what to
 		 *            supply for this item.
 		 * @param maskValue
 		 *            true if the value should be masked from displaying during
 		 *            input. This should be true for passwords and other
 		 *            secrets, false for names and other public data.
 		 */
 		public StringType(String promptText, boolean maskValue) {
 			super(promptText, maskValue);
 		}
 
 		@Override
 		public void clear() {
 			value = null;
 		}
 
 		/** @return the current value */
 		public String getValue() {
 			return value;
 		}
 
 		/**
 		 *
 		 * @param newValue
 		 */
 		public void setValue(String newValue) {
 			value = newValue;
 		}
 	}
 
 	/** An item whose value is stored as a char[] and is therefore clearable. */
 	public static class CharArrayType extends CredentialItem {
 		private char[] value;
 
 		/**
 		 * Initialize a prompt for a secure value stored in a character array.
 		 *
 		 * @param promptText
 		 *            prompt to display to the user alongside of the input
 		 *            field. Should be sufficient text to indicate what to
 		 *            supply for this item.
 		 * @param maskValue
 		 *            true if the value should be masked from displaying during
 		 *            input. This should be true for passwords and other
 		 *            secrets, false for names and other public data.
 		 */
 		public CharArrayType(String promptText, boolean maskValue) {
 			super(promptText, maskValue);
 		}
 
 		/** Destroys the current value, clearing the internal array. */
 		@Override
 		public void clear() {
 			if (value != null) {
 				Arrays.fill(value, (char) 0);
 				value = null;
 			}
 		}
 
 		/**
 		 * Get the current value.
 		 *
 		 * The returned array will be cleared out when {@link #clear()} is
 		 * called. Callers that need the array elements to survive should delay
 		 * invoking {@code clear()} until the value is no longer necessary.
 		 *
 		 * @return the current value array. The actual internal array is
 		 *         returned, reducing the number of copies present in memory.
 		 */
 		public char[] getValue() {
 			return value;
 		}
 
 		/**
 		 * Set the new value, clearing the old value array.
 		 *
 		 * @param newValue
 		 *            if not null, the array is copied.
 		 */
 		public void setValue(char[] newValue) {
 			clear();
 
 			if (newValue != null) {
 				value = new char[newValue.length];
 				System.arraycopy(newValue, 0, value, 0, newValue.length);
 			}
 		}
 
 		/**
 		 * Set the new value, clearing the old value array.
 		 *
 		 * @param newValue
 		 *            the new internal array. The array is <b>NOT</b> copied.
 		 */
 		public void setValueNoCopy(char[] newValue) {
 			clear();
 			value = newValue;
 		}
 	}
 
 	/** An item whose value is a boolean choice, presented as Yes/No. */
 	public static class YesNoType extends CredentialItem {
 		private boolean value;
 
 		/**
 		 * Initialize a prompt for a single boolean answer.
 		 *
 		 * @param promptText
 		 *            prompt to display to the user alongside of the input
 		 *            field. Should be sufficient text to indicate what to
 		 *            supply for this item.
 		 */
 		public YesNoType(String promptText) {
 			super(promptText, false);
 		}
 
 		@Override
 		public void clear() {
 			value = false;
 		}
 
 		/** @return the current value */
 		public boolean getValue() {
 			return value;
 		}
 
 		/**
 		 * Set the new value.
 		 *
 		 * @param newValue
 		 */
 		public void setValue(boolean newValue) {
 			value = newValue;
 		}
 	}
 
 	/** An advice message presented to the user, with no response required. */
 	public static class InformationalMessage extends CredentialItem {
 		/**
 		 * Initialize an informational message.
 		 *
 		 * @param messageText
 		 *            message to display to the user.
 		 */
 		public InformationalMessage(String messageText) {
 			super(messageText, false);
 		}
 
 		@Override
 		public void clear() {
 			// Nothing to clear.
 		}
 	}
 
 	/** Prompt for a username, which is not masked on input. */
 	public static class Username extends StringType {
 		/** Initialize a new username item, with a default username prompt. */
 		public Username() {
 			super(JGitText.get().credentialUsername, false);
 		}
 	}
 
 	/** Prompt for a password, which is masked on input. */
 	public static class Password extends CharArrayType {
 		/** Initialize a new password item, with a default password prompt. */
 		public Password() {
 			super(JGitText.get().credentialPassword, true);
 		}
 
 		/**
 		 * Initialize a new password item, with given prompt.
 		 *
 		 * @param msg
 		 *            prompt message
 		 */
 		public Password(String msg) {
 			super(msg, true);
 		}
 	}
 }