Coverage Report

Coverage Report - com.allanbank.mongodb.Credential

Classes in this File
Line Coverage
Branch Coverage
Complexity
Credential
94%
91/96
96%
56/58
1.886
Credential$Builder
96%
49/51
83%
5/6
1.886
 /*
  * #%L
  * Credential.java - mongodb-async-driver - Allanbank Consulting, Inc.
  * %%
  * Copyright (C) 2011 - 2014 Allanbank Consulting, 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.
  * #L%
  */
 package com.allanbank.mongodb;
 
 import java.io.File;
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.Serializable;
 import java.security.cert.X509Certificate;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
 import com.allanbank.mongodb.client.connection.auth.Authenticator;
 import com.allanbank.mongodb.client.connection.auth.MongoDbAuthenticator;
 import com.allanbank.mongodb.error.MongoDbAuthenticationException;
 
 /**
  * Credential provides an immutable set of credential for accessing MongoDB.
  * <p>
  * A given client can support a different set of credential for each database
  * the client is accessing. The client can also authenticate against the
  * {@value #ADMIN_DB} database which will apply across all databases.
  * </p>
  * <p>
  * <em>Note:</em> While we use the term user name/password within this class the
  * values may not actually be a user name or a password. In addition not all
  * authentication mechanisms may use all of the fields in this class. See the
  * documentation for the authenticator being used for details on what values are
  * expected for each of the fields in this class.
  * </p>
  * 
  * @see <a
  *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication.html">Authentication
  *      Usage Guide</a>
  * @api.yes This class is part of the driver's API. Public and protected members
  *          will be deprecated for at least 1 non-bugfix release (version
  *          numbers are &lt;major&gt;.&lt;minor&gt;.&lt;bugfix&gt;) before being
  *          removed or modified.
  * @copyright 2013, Allanbank Consulting, Inc., All Rights Reserved
  */
 public final class Credential implements Serializable {
 
     /**
      * The name of the administration database used to authenticate a
      * administrator to MongoDB.
      */
     public static final String ADMIN_DB = "admin";
 
     /**
      * Constant for Kerberos authentication.
      * <p>
      * <em>Note:</em> Use of the Kerberos for authentication requires the
      * driver's extensions. See the <a href=
      * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/kerberos.html"
      * >Kerberos Usage Guide</a> for details.
      * </p>
      * 
      * @see <a
      *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/kerberos.html">Kerberos
      *      Usage Guide</a>
      */
     public static final String KERBEROS;
 
     /** Constant for traditional MongoDB Challenge/Response. */
     public static final String MONGODB_CR;
 
     /** An empty password array. */
     public static final char[] NO_PASSWORD = new char[0];
 
     /**
      * Constant for authentication using plain SASL (LDAP/PAM) client
      * certificates passed at connection establishment.
      * <p>
      * <em>Note:</em> Use of Plain SASL for authentication requires the driver's
      * extensions. See the <a href=
      * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html"
      * >Plain SASL Usage Guide</a> for details.
      * </p>
      * 
      * @see <a
      *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html">Plain
      *      SASL Usage Guide</a>
      */
     public static final String PLAIN_SASL;
 
     /**
      * Constant for authentication using x.509 client certificates passed at
      * connection establishment.
      * <p>
      * <em>Note:</em> Use of the x.509 for authentication requires the driver's
      * extensions. See the <a href=
      * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/tls.html"
      * >TLS/SSL Usage Guide</a> for details.
      * </p>
      * 
      * @see <a
      *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/tls.html">TLS/SSL
      *      Usage Guide</a>
      * @see <a
      *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/x509.html">x.509
      *      Authentication Usage Guide</a>
      */
     public static final String X509;
 
     /** Serialization version of the class. */
     private static final long serialVersionUID = -6251469373336569336L;
 
     static {
         KERBEROS = "com.allanbank.mongodb.extensions.authentication.KerberosAuthenticator";
         MONGODB_CR = MongoDbAuthenticator.class.getName();
         PLAIN_SASL = "com.allanbank.mongodb.extensions.authentication.PlainSaslAuthenticator";
         X509 = "com.allanbank.mongodb.extensions.authentication.X509Authenticator";
     }
 
     /**
      * Creates a {@link Builder} for creating a {@link Credential}.
      * 
      * @return The {@link Builder} for creating a {@link Credential}.
      */
     public static Builder builder() {
         return new Builder();
     }
 
     /**
      * The authentication type or mode that the credential should be used with.
      */
     private final String myAuthenticationType;
 
     /** The template authenticator for the credential. */
     private transient Authenticator myAuthenticator;
 
     /** The database the credential are valid for. */
     private final String myDatabase;
 
     /** The file containing the full credentials. */
     private final File myFile;
 
     /** Other options for the credentials. */
     private final Map<String, String> myOptions;
 
     /** The password for the credential set. */
     private final char[] myPassword;
 
     /** The user name for the credential set. */
     private final String myUserName;
 
     /**
      * Creates a new Credential.
      * 
      * @param builder
      *            The builder for the credentials.
      */
     public Credential(final Builder builder) {
         myUserName = builder.myUserName;
         myDatabase = builder.myDatabase;
         myFile = builder.myFile;
         myAuthenticationType = builder.myAuthenticationType;
         myAuthenticator = builder.myAuthenticator;
         myPassword = builder.myPassword.clone();
         myOptions = Collections.unmodifiableMap(new HashMap<String, String>(
                 builder.myOptions));
     }
 
     /**
      * Returns an authenticator for the credential.
      * 
      * @return The authenticator for the credential.
      * @throws MongoDbAuthenticationException
      *             On a failure to load the authenticator for the credential.
      */
     public Authenticator authenticator() throws MongoDbAuthenticationException {
         if (myAuthenticator == null) {
             try {
                 loadAuthenticator();
             }
             catch (final ClassNotFoundException e) {
                 throw new MongoDbAuthenticationException(e);
             }
             catch (final InstantiationException e) {
                 throw new MongoDbAuthenticationException(e);
             }
             catch (final IllegalAccessException e) {
                 throw new MongoDbAuthenticationException(e);
             }
         }
 
         return myAuthenticator.clone();
     }
 
     /**
      * {@inheritDoc}
      * <p>
      * Overridden to return true if the passed value equals these credential.
      * </p>
      */
     @Override
     public boolean equals(final Object object) {
         boolean result = false;
         if (this == object) {
             result = true;
         }
         else if ((object != null) && (getClass() == object.getClass())) {
             final Credential other = (Credential) object;
 
             result = nullSafeEquals(myAuthenticationType,
                     other.myAuthenticationType)
                     && nullSafeEquals(myDatabase, other.myDatabase)
                     && nullSafeEquals(myUserName, other.myUserName)
                     && nullSafeEquals(myFile, other.myFile)
                     && nullSafeEquals(myOptions, other.myOptions)
                     && Arrays.equals(myPassword, other.myPassword);
         }
         return result;
     }
 
     /**
      * Returns the authentication type or mode that the credential should be
      * used with.
      * 
      * @return The authentication type or mode that the credential should be
      *         used with.
      */
     public String getAuthenticationType() {
         return myAuthenticationType;
     }
 
     /**
      * Returns the authenticator value.
      * 
      * @return The authenticator value.
      */
     public Authenticator getAuthenticator() {
         return myAuthenticator;
     }
 
     /**
      * Returns the database the credential are valid for. Use {@link #ADMIN_DB}
      * to authenticate as an administrator.
      * 
      * @return The database the credential are valid for.
      */
     public String getDatabase() {
         return myDatabase;
     }
 
     /**
      * Returns the file containing the full credentials.
      * 
      * @return The file containing the full credentials. May be
      *         <code>null</code>.
      */
     public File getFile() {
         return myFile;
     }
 
     /**
      * Returns the option value.
      * 
      * @param optionName
      *            The name of the option to set.
      * @param defaultValue
      *            The value of the option if it is not set or cannot be parsed
      *            via {@link Boolean#parseBoolean(String)}.
      * @return The option value.
      */
     public boolean getOption(final String optionName, final boolean defaultValue) {
         final String value = myOptions.get(optionName);
         if (value != null) {
             return Boolean.parseBoolean(value);
         }
         return defaultValue;
     }
 
     /**
      * Returns the option value.
      * 
      * @param optionName
      *            The name of the option to set.
      * @param defaultValue
      *            The value of the option if it is not set or cannot be parsed
      *            via {@link Integer#parseInt(String)}.
      * @return The option value.
      */
     public int getOption(final String optionName, final int defaultValue) {
         final String value = myOptions.get(optionName);
         if (value != null) {
             try {
                 return Integer.parseInt(value);
             }
             catch (final NumberFormatException nfe) {
                 return defaultValue;
             }
         }
         return defaultValue;
     }
 
     /**
      * Returns the option value.
      * 
      * @param optionName
      *            The name of the option to set.
      * @param defaultValue
      *            The value of the option if it is not set.
      * @return The option value.
      */
     public String getOption(final String optionName, final String defaultValue) {
         String value = myOptions.get(optionName);
         if (value == null) {
             value = defaultValue;
         }
 
         return value;
     }
 
     /**
      * Returns the password for the credential set. A clone of the internal
      * array is returns that should be cleared when it is done being used via
      * something like {@link java.util.Arrays#fill(char[], char)
      * Arrays.fill(password, 0)}
      * 
      * @return The password for the credential set.
      */
     public char[] getPassword() {
         return myPassword.clone();
     }
 
     /**
      * Returns the user name for the credential set.
      * 
      * @return The user name for the credential set.
      */
     public String getUserName() {
         return myUserName;
     }
 
     /**
      * {@inheritDoc}
      * <p>
      * Overridden to hash the credential.
      * </p>
      */
     @Override
     public int hashCode() {
         int result = 1;
 
         result = (31 * result)
                 + ((myAuthenticationType == null) ? 0 : myAuthenticationType
                         .hashCode());
         result = (31 * result)
                 + ((myDatabase == null) ? 0 : myDatabase.hashCode());
         result = (31 * result) + myOptions.hashCode();
         result = (31 * result) + Arrays.hashCode(myPassword);
         result = (31 * result)
                 + ((myUserName == null) ? 0 : myUserName.hashCode());
         result = (31 * result) + ((myFile == null) ? 0 : myFile.hashCode());
 
         return result;
     }
 
     /**
      * Returns true if the password has atleast a single character.
      * 
      * @return True if the password has atleast a single character, false
      *         otherwise.
      */
     public boolean hasPassword() {
         return (myPassword.length > 0);
     }
 
     /**
      * {@inheritDoc}
      * <p>
      * Overridden to returns the credential in a human readable form.
      * </p>
      */
     @Override
     public String toString() {
         final StringBuilder builder = new StringBuilder();
         builder.append("{ username : '");
         builder.append(myUserName);
         builder.append("', database : '");
         builder.append(myDatabase);
         if (myFile != null) {
             builder.append("', file : '");
             builder.append(myFile.getName());
         }
         builder.append("', password : '<redacted>', type: '");
         if (KERBEROS.equals(myAuthenticationType)) {
             builder.append("KERBEROS");
         }
         else if (PLAIN_SASL.equals(myAuthenticationType)) {
             builder.append("PLAIN SASL");
         }
         else if (X509.equals(myAuthenticationType)) {
             builder.append("x.509");
         }
         else if (MONGODB_CR.equals(myAuthenticationType)) {
             builder.append("MONGODB-CR");
         }
         else if (myAuthenticationType != null) {
             builder.append(myAuthenticationType);
         }
 
         for (final Map.Entry<String, String> option : myOptions.entrySet()) {
             builder.append("', '");
             builder.append(option.getKey());
             builder.append("': '");
             builder.append(option.getValue());
         }
 
         builder.append("' }");
 
         return builder.toString();
     }
 
     /**
      * Loads the authenticator for the credential.
      * 
      * @throws ClassNotFoundException
      *             If the authenticators Class cannot be found.
      * @throws InstantiationException
      *             If the authenticator cannot be instantiated.
      * @throws IllegalAccessException
      *             If the authenticator cannot be accessed.
      */
     /* package */void loadAuthenticator() throws ClassNotFoundException,
             InstantiationException, IllegalAccessException {
         if (myAuthenticator == null) {
             myAuthenticator = (Authenticator) Class.forName(
                     getAuthenticationType()).newInstance();
         }
     }
 
     /**
      * Does a null safe equals comparison.
      * 
      * @param rhs
      *            The right-hand-side of the comparison.
      * @param lhs
      *            The left-hand-side of the comparison.
      * @return True if the rhs equals the lhs. Note: nullSafeEquals(null, null)
      *         returns true.
      */
     private boolean nullSafeEquals(final Object rhs, final Object lhs) {
         return (rhs == lhs) || ((rhs != null) && rhs.equals(lhs));
     }
 
     /**
      * Sets the transient state of this {@link Credential}.
      * 
      * @param in
      *            The input stream.
      * @throws ClassNotFoundException
      *             On a failure loading a class in this classed reachable tree.
      * @throws IOException
      *             On a failure reading from the stream.
      */
     private void readObject(final ObjectInputStream in)
             throws ClassNotFoundException, IOException {
         in.defaultReadObject();
         myAuthenticator = null;
     }
 
     /**
      * Builder provides a helper for creating a {@link Credential}.
      * 
      * @copyright 2013, Allanbank Consulting, Inc., All Rights Reserved
      */
     public static class Builder {
         /**
          * The authentication type or mode that the credential should be used
          * with.
          */
         protected String myAuthenticationType;
 
         /** The template authenticator for the credential. */
         protected Authenticator myAuthenticator;
 
         /** The database the credential are valid for. */
         protected String myDatabase;
 
         /** The file containing the full credentials. */
         protected File myFile;
 
         /** Other options for the credentials. */
         protected final Map<String, String> myOptions;
 
         /** The password for the credential set. */
         protected char[] myPassword;
 
         /** The user name for the credential set. */
         protected String myUserName;
 
         /**
          * Creates a new Builder.
          */
         public Builder() {
             myOptions = new HashMap<String, String>();
             reset();
         }
 
         /**
          * Adds an option to the built credentials.
          * 
          * @param optionName
          *            The name of the option to set.
          * @param optionValue
          *            The value of the option to set.
          * @return This {@link Builder} for method chaining.
          */
         public Builder addOption(final String optionName,
                 final boolean optionValue) {
             myOptions.put(optionName, String.valueOf(optionValue));
 
             return this;
         }
 
         /**
          * Adds an option to the built credentials.
          * 
          * @param optionName
          *            The name of the option to set.
          * @param optionValue
          *            The value of the option to set.
          * @return This {@link Builder} for method chaining.
          */
         public Builder addOption(final String optionName, final int optionValue) {
             myOptions.put(optionName, String.valueOf(optionValue));
 
             return this;
         }
 
         /**
          * Adds an option to the built credentials.
          * 
          * @param optionName
          *            The name of the option to set.
          * @param optionValue
          *            The value of the option to set.
          * @return This {@link Builder} for method chaining.
          */
         public Builder addOption(final String optionName,
                 final String optionValue) {
             myOptions.put(optionName, optionValue);
 
             return this;
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with.
          * <p>
          * This method delegates to {@link #setAuthenticationType(String)}.
          * </p>
          * 
          * @param authenticationType
          *            The new value for the authentication type or mode that the
          *            credential should be used with.
          * @return This {@link Builder} for method chaining.
          */
         public Builder authenticationType(final String authenticationType) {
             return setAuthenticationType(authenticationType);
         }
 
         /**
          * Sets the value of the template authenticator for the credential.
          * <p>
          * This method delegates to {@link #setAuthenticator(Authenticator)}.
          * </p>
          * 
          * @param authenticator
          *            The new value for the template authenticator for the
          *            credential.
          * @return This {@link Builder} for method chaining.
          */
         public Builder authenticator(final Authenticator authenticator) {
             return setAuthenticator(authenticator);
         }
 
         /**
          * Creates the credential from this builder.
          * 
          * @return The {@link Credential} populated with the state of this
          *         builder.
          */
         public Credential build() {
             return new Credential(this);
         }
 
         /**
          * Sets the value of the database the credential are valid for.
          * <p>
          * This method delegates to {@link #setDatabase(String)}.
          * </p>
          * 
          * @param database
          *            The new value for the database the credential are valid
          *            for.
          * @return This {@link Builder} for method chaining.
          */
         public Builder database(final String database) {
             return setDatabase(database);
         }
 
         /**
          * Sets the value of the file containing the full credentials.
          * <p>
          * This method delegates to {@link #setFile(File)}.
          * </p>
          * 
          * @param file
          *            The new value for the file containing the full
          *            credentials.
          * @return This {@link Builder} for method chaining.
          */
         public Builder file(final File file) {
             return setFile(file);
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with to Kerberos.
          * <p>
          * This method delegates to {@link #setAuthenticationType(String)
          * setAuthenticationType(KERBEROS)}.
          * </p>
          * <p>
          * <em>Note:</em> Use of Kerberos for authentication requires the
          * driver's extensions. See the <a href=
          * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/kerberos.html"
          * >Kerberos Usage Guide</a> for details.
          * </p>
          * 
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/kerberos.html">Kerberos
          *      Usage Guide</a>
          * 
          * @return This {@link Builder} for method chaining.
          */
         public Builder kerberos() {
             return setAuthenticationType(KERBEROS);
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with LDAP via PLAIN SASL.
          * <p>
          * This method delegates to {@link #setAuthenticationType(String)
          * setAuthenticationType(PLAIN_SASL)}.
          * </p>
          * <p>
          * <em>Note:</em> Use of Plain SASL for authentication requires the
          * driver's extensions. See the <a href=
          * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html"
          * >Plain SASL Usage Guide</a> for details.
          * </p>
          * 
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html">Plain
          *      SASL Usage Guide</a>
          * 
          * @return This {@link Builder} for method chaining.
          */
         public Builder ldap() {
             return setAuthenticationType(PLAIN_SASL);
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with to MongoDB Challenge/Response.
          * <p>
          * This method delegates to {@link #setAuthenticationType(String)
          * setAuthenticationType(MONGODB_CR)}.
          * </p>
          * 
          * @return This {@link Builder} for method chaining.
          */
         public Builder mongodbCR() {
             return setAuthenticationType(MONGODB_CR);
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with PAM via PLAIN SASL.
          * <p>
          * This method delegates to {@link #setAuthenticationType(String)
          * setAuthenticationType(PLAIN_SASL)}.
          * </p>
          * <p>
          * <em>Note:</em> Use of Plain SASL for authentication requires the
          * driver's extensions. See the <a href=
          * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html"
          * >Plain SASL Usage Guide</a> for details.
          * </p>
          * 
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html">Plain
          *      SASL Usage Guide</a>
          * 
          * @return This {@link Builder} for method chaining.
          */
         public Builder pam() {
             return setAuthenticationType(PLAIN_SASL);
         }
 
         /**
          * Sets the value of the password for the credential set.
          * <p>
          * This method delegates to {@link #setPassword(char[])}.
          * </p>
          * 
          * @param password
          *            The new value for the password for the credential set.
          * @return This {@link Builder} for method chaining.
          */
         public Builder password(final char[] password) {
             return setPassword(password);
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with to PLAIN SASL.
          * <p>
          * This method delegates to {@link #setAuthenticationType(String)
          * setAuthenticationType(PLAIN_SASL)}.
          * </p>
          * <p>
          * <em>Note:</em> Use of Plain SASL for authentication requires the
          * driver's extensions. See the <a href=
          * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html"
          * >Plain SASL Usage Guide</a> for details.
          * </p>
          * 
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/plain_sasl.html">Plain
          *      SASL Usage Guide</a>
          * 
          * @return This {@link Builder} for method chaining.
          */
         public Builder plainSasl() {
             return setAuthenticationType(PLAIN_SASL);
         }
 
         /**
          * Resets the builder to a known state.
          * 
          * @return This {@link Builder} for method chaining.
          */
         public Builder reset() {
             if (myPassword != null) {
                 Arrays.fill(myPassword, '\u0000');
             }
 
             myAuthenticationType = MONGODB_CR;
             myAuthenticator = null;
             myDatabase = ADMIN_DB;
             myFile = null;
             myPassword = NO_PASSWORD;
             myUserName = null;
             myOptions.clear();
 
             return this;
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with.
          * 
          * @param authenticationType
          *            The new value for the authentication type or mode that the
          *            credential should be used with.
          * @return This {@link Builder} for method chaining.
          */
         public Builder setAuthenticationType(final String authenticationType) {
             myAuthenticationType = authenticationType;
             return this;
         }
 
         /**
          * Sets the value of the template authenticator for the credential.
          * 
          * @param authenticator
          *            The new value for the template authenticator for the
          *            credential.
          * @return This {@link Builder} for method chaining.
          */
         public Builder setAuthenticator(final Authenticator authenticator) {
             myAuthenticator = authenticator;
             return this;
         }
 
         /**
          * Sets the value of the database the credential are valid for.
          * 
          * @param database
          *            The new value for the database the credential are valid
          *            for.
          * @return This {@link Builder} for method chaining.
          */
         public Builder setDatabase(final String database) {
             if (database == null) {
                 myDatabase = ADMIN_DB;
             }
             else {
                 myDatabase = database;
             }
             return this;
         }
 
         /**
          * Sets the value of the file containing the full credentials.
          * 
          * @param file
          *            The new value for the file containing the full
          *            credentials.
          * @return This {@link Builder} for method chaining.
          */
         public Builder setFile(final File file) {
             myFile = file;
             return this;
         }
 
         /**
          * Sets the value of the password for the credential set.
          * 
          * @param password
          *            The new value for the password for the credential set.
          * @return This {@link Builder} for method chaining.
          */
         public Builder setPassword(final char[] password) {
             Arrays.fill(myPassword, '\u0000');
 
             if (password == null) {
                 myPassword = NO_PASSWORD;
             }
             else {
                 myPassword = password.clone();
             }
             return this;
         }
 
         /**
          * Sets the value of the user name for the credential set.
          * 
          * @param userName
          *            The new value for the user name for the credential set.
          * @return This {@link Builder} for method chaining.
          */
         public Builder setUserName(final String userName) {
             myUserName = userName;
             return this;
         }
 
         /**
          * Sets the value of the user name for the credential set.
          * <p>
          * This method delegates to {@link #setUserName(String)}.
          * </p>
          * 
          * @param userName
          *            The new value for the user name for the credential set.
          * @return This {@link Builder} for method chaining.
          */
         public Builder userName(final String userName) {
             return setUserName(userName);
         }
 
         /**
          * Sets the value of the authentication type or mode that the credential
          * should be used with to x.509 client certificates exchanged via the
          * TLS connection.
          * <p>
          * This method delegates to {@link #setAuthenticationType(String)
          * setAuthenticationType(X509)}.
          * </p>
          * <p>
          * <em>Note:</em> Use of x.509 for authentication requires the driver's
          * extensions. See the <a href=
          * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/tls.html"
          * > TLS Usage Guide</a> for details.
          * </p>
          * 
          * @return This {@link Builder} for method chaining.
          * 
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/tls.html">TLS/SSL
          *      Usage Guide</a>
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/x509.html">x.509
          *      Authentication Usage Guide</a>
          */
         public Builder x509() {
             return setAuthenticationType(X509);
         }
 
         /**
          * Sets the {@link #userName(String) user name} to that of the x.509
          * certificate subject name and then sets the value of the
          * authentication type or mode that the credential should be used with
          * to x.509 client certificates exchanged via the TLS connection.
          * <p>
          * This method delegates to {@link #userName(String)
          * userName(cert.getSubjectX500Principal().toString())}.{@link #x509()
          * x509()}.
          * </p>
          * <p>
          * <em>Note:</em> Use of x.509 for authentication requires the driver's
          * extensions. See the <a href=
          * "http://www.allanbank.com/mongodb-async-driver/userguide/authentication/tls.html"
          * > TLS Usage Guide</a> for details.
          * </p>
          * 
          * @param cert
          *            The client's certificate containing the client subject
          *            name.
          * @return This {@link Builder} for method chaining.
          * 
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/tls.html">TLS/SSL
          *      Usage Guide</a>
          * @see <a
          *      href="http://www.allanbank.com/mongodb-async-driver/userguide/authentication/x509.html">x.509
          *      Authentication Usage Guide</a>
          */
         public Builder x509(final X509Certificate cert) {
             return userName(cert.getSubjectX500Principal().toString()).x509();
         }
     }
 }