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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.email.mail;
     18 
     19 import com.android.emailcommon.mail.CertificateValidationException;
     20 import com.android.emailcommon.mail.MessagingException;
     21 
     22 import java.io.IOException;
     23 import java.io.InputStream;
     24 import java.io.OutputStream;
     25 import java.net.InetAddress;
     26 import java.net.SocketException;
     27 
     28 /**
     29  * This interface defines a "transport", which is defined here as being one layer below the
     30  * specific wire protocols such as POP3, IMAP, or SMTP.
     31  *
     32  * Practically speaking, it provides a definition of the common functionality between them
     33  * (dealing with sockets & streams, SSL, logging, and so forth), and provides a seam just below
     34  * the individual protocols to enable better testing.
     35  *
     36  * The following features are supported and presumed to be common:
     37  *
     38  *  Interpretation of URI
     39  *  Support for SSL and TLS wireline security
     40  */
     41 public interface Transport extends Cloneable {
     42 
     43     /**
     44      * Connection security options for transport that supports SSL and/or TLS
     45      */
     46     public static final int CONNECTION_SECURITY_NONE = 0;
     47     public static final int CONNECTION_SECURITY_SSL = 1;
     48     public static final int CONNECTION_SECURITY_TLS = 2;
     49 
     50     /**
     51      * Get a new transport, using an existing one as a model.  The new transport is configured as if
     52      * setUri() and setSecurity() have been called, but not opened or connected in any way.
     53      * @return a new Transport ready to open()
     54      */
     55     public Transport clone();
     56 
     57     /**
     58      * Sets the host
     59      */
     60     public void setHost(String host);
     61 
     62     /**
     63      * Sets the port
     64      */
     65     public void setPort(int port);
     66 
     67     /**
     68      * Returns the host or {@code null} if none was specified.
     69      */
     70     public String getHost();
     71 
     72     /**
     73      * Returns the port or {@code 0} if none was specified.
     74      */
     75     public int getPort();
     76 
     77     /**
     78      * Set the desired security mode for this connection.
     79      * @param connectionSecurity A value indicating the desired security mode.
     80      * @param trustAllCertificates true to allow unverifiable certificates to be used
     81      */
     82     public void setSecurity(int connectionSecurity, boolean trustAllCertificates);
     83 
     84     /**
     85      * @return Returns the desired security mode for this connection.
     86      */
     87     public int getSecurity();
     88 
     89     /**
     90      * @return true if the security mode indicates that SSL is possible
     91      */
     92     public boolean canTrySslSecurity();
     93 
     94     /**
     95      * @return true if the security mode indicates that TLS is possible
     96      */
     97     public boolean canTryTlsSecurity();
     98 
     99     /**
    100      * @return true if the security mode indicates that all certificates can be trusted
    101      */
    102     public boolean canTrustAllCertificates();
    103 
    104     /**
    105      * Set the socket timeout.
    106      * @param timeoutMilliseconds the read timeout value if greater than {@code 0}, or
    107      *            {@code 0} for an infinite timeout.
    108      */
    109     public void setSoTimeout(int timeoutMilliseconds) throws SocketException;
    110 
    111         /**
    112      * Attempts to open the connection using the supplied parameters, and using SSL if indicated.
    113      */
    114     public void open() throws MessagingException, CertificateValidationException;
    115 
    116     /**
    117      * Attempts to reopen the connection using TLS.
    118      */
    119     public void reopenTls() throws MessagingException;
    120 
    121     /**
    122      * @return true if the connection is open
    123      */
    124     public boolean isOpen();
    125 
    126     /**
    127      * Closes the connection.  Does not send any closure messages, simply closes the socket and the
    128      * associated streams.  Best effort only.  Catches all exceptions and always returns.
    129      *
    130      * MUST NOT throw any exceptions.
    131      */
    132     public void close();
    133 
    134     /**
    135      * @return returns the active input stream
    136      */
    137     public InputStream getInputStream();
    138 
    139     /**
    140      * @return returns the active output stream
    141      */
    142     public OutputStream getOutputStream();
    143 
    144     /**
    145      * Write a single line to the server, and may generate a log entry (if enabled).
    146      * @param s The text to send to the server.
    147      * @param sensitiveReplacement If the command includes sensitive data (e.g. authentication)
    148      * please pass a replacement string here (for logging).  Most callers simply pass null,
    149      */
    150     void writeLine(String s, String sensitiveReplacement) throws IOException;
    151 
    152     /**
    153      * Reads a single line from the server.  Any delimiter characters will not be included in the
    154      * result.  May generate a log entry, if enabled.
    155      * @return Returns the string from the server.
    156      * @throws IOException
    157      */
    158     String readLine() throws IOException;
    159 
    160     /**
    161      * @return The local address.  If we have an open socket, get the local address from this.
    162      *     Otherwise simply use {@link InetAddress#getLocalHost}.
    163      */
    164     InetAddress getLocalAddress() throws IOException;
    165 }
    166