Redesign of StreamProvider in Part

Signed-off-by: Jorge Bescos Gascon <jorge.bescos.gascon@oracle.com>

api/src/main/java/jakarta/mail/BodyPart.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -39,13 +39,6 @@ public abstract class BodyPart implements Part {
      */
     protected Multipart parent;
 
-    /**
-     * Instance of stream provider.
-     *
-     * @since JavaMail 2.1
-     */
-    protected final StreamProvider streamProvider = StreamProvider.provider();
-
     /**
      * Creates a default {@code BodyPart}.
      */
@@ -74,4 +67,14 @@ public Multipart getParent() {
     void setParent(Multipart parent) {
         this.parent = parent;
     }
+
+    @Override
+    public StreamProvider getStreamProvider() throws MessagingException {
+        if (parent != null) {
+            return parent.getStreamProvider();
+        } else {
+            return Part.super.getStreamProvider();
+        }
+    }
+
 }

api/src/main/java/jakarta/mail/Message.java

@@ -708,32 +708,21 @@ public boolean match(SearchTerm term) throws MessagingException {
         return term.match(this);
     }
 
-    /**
-     * Obtains the {@link StreamProvider} from the session, if exists.
-     * Otherwise it obtains it from
-     * {@link Session#getDefaultInstance(java.util.Properties, Authenticator)}.
-     *
-     * @return the StreamProvider implementation from the session.
-     * @throws MessagingException if errors.
-     *
-     * @since JavaMail 2.2
-     */
-    protected StreamProvider provider() throws MessagingException {
+    @Override
+    public StreamProvider getStreamProvider() throws MessagingException {
         try {
             try {
                 final Session s = this.session;
                 if (s != null) {
                     return s.getStreamProvider();
                 } else {
-                    return Session.getDefaultInstance(System.getProperties(),
-                        null).getStreamProvider();
+                    return Session.getDefaultInstance(System.getProperties(), null).getStreamProvider();
                 }
             } catch (ServiceConfigurationError sce) {
                 throw new IllegalStateException(sce);
             }
         } catch (RuntimeException re) {
-            throw new MessagingException("Unable to get "
-                    + StreamProvider.class.getName(), re);
+            throw new MessagingException("Unable to get " + StreamProvider.class.getName(), re);
         }
     }
 }

api/src/main/java/jakarta/mail/Multipart.java

@@ -21,8 +21,6 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.Vector;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 
 /**
  * Multipart is a container that holds multiple body parts. Multipart
@@ -44,7 +42,6 @@
 
 public abstract class Multipart {
 
-    private static final Logger LOGGER = Logger.getLogger(Multipart.class.getName());
     /**
      * Vector of BodyPart objects.
      */
@@ -64,13 +61,6 @@ public abstract class Multipart {
      */
     protected Part parent;
 
-    /**
-     * Instance of stream provider.
-     *
-     * @since JavaMail 2.2
-     */
-    private volatile StreamProvider streamProvider;
-
     /**
      * Default constructor. An empty Multipart object is created.
      */
@@ -270,26 +260,23 @@ public synchronized void setParent(Part parent) {
         this.parent = parent;
     }
 
-    protected StreamProvider provider() {
-        if (streamProvider == null) {
-            synchronized (this) {
-                if (streamProvider == null) {
-                    if (parent != null && parent instanceof Message) {
-                        try {
-                            streamProvider = ((Message)parent).provider();
-                        } catch (MessagingException e) {
-                            if (LOGGER.isLoggable(Level.FINE)) {
-                                LOGGER.log(Level.FINE, "Cannot reuse streamProvider", e);
-                            }
-                        }
-                    }
-                }
-                if (streamProvider == null) {
-                    streamProvider = StreamProvider.provider();
-                }
-            }
+    /**
+     * Obtains the {@link StreamProvider} from the parent, if possible.
+     * Otherwise it obtains it from
+     * {@link Session#getDefaultInstance(java.util.Properties, Authenticator)}.
+     *
+     * @return the StreamProvider implementation from the session.
+     * @throws MessagingException if errors.
+     *
+     * @since JavaMail 2.2
+     */
+    protected StreamProvider getStreamProvider() throws MessagingException {
+        Part parent = this.parent;
+        if (parent != null) {
+            return parent.getStreamProvider();
+        } else {
+            return Session.getDefaultInstance(System.getProperties(), null).getStreamProvider();
         }
-        return streamProvider;
     }
 
 }

api/src/main/java/jakarta/mail/Part.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -17,6 +17,7 @@
 package jakarta.mail;
 
 import jakarta.activation.DataHandler;
+import jakarta.mail.util.StreamProvider;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -85,7 +86,7 @@ public interface Part {
      * of the content. The size is appropriate for display in a
      * user interface to give the user a rough idea of the size
      * of this part.
-     *
+     *StreamProvider getStreamProvider() throws MessagingException
      * @return size of content in bytes
      * @throws MessagingException for failures
      */
@@ -210,7 +211,7 @@ public interface Part {
     void setDescription(String description) throws MessagingException;
 
     /**
-     * Get the filename associated with this part, if possible.
+     * Get the filename associated with this part, if possible.StreamProvider getStreamProvider() throws MessagingException
      * Useful if this part represents an "attachment" that was
      * loaded from a file.  The filename will usually be a simple
      * name, not including directory components.
@@ -453,4 +454,17 @@ Enumeration<Header> getMatchingHeaders(String[] header_names)
      */
     Enumeration<Header> getNonMatchingHeaders(String[] header_names)
             throws MessagingException;
+
+    /**
+     * Obtains the {@link StreamProvider}.
+     * It defaults to {@link Session#getDefaultInstance(java.util.Properties, Authenticator)}.
+     *
+     * @return the StreamProvider.
+     * @throws MessagingException if errors.
+     *
+     * @since JavaMail 2.2
+     */
+    default StreamProvider getStreamProvider() throws MessagingException {
+        return Session.getDefaultInstance(System.getProperties(), null).getStreamProvider();
+    }
 }

api/src/main/java/jakarta/mail/internet/MimeBodyPart.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -30,7 +30,6 @@
 import jakarta.mail.Multipart;
 import jakarta.mail.Part;
 import jakarta.mail.util.LineOutputStream;
-import jakarta.mail.util.StreamProvider;
 import jakarta.mail.util.StreamProvider.EncoderTypes;
 
 import java.io.BufferedInputStream;
@@ -1630,7 +1629,7 @@ static void invalidateContentHeaders(MimePart part)
         part.removeHeader("Content-Type");
         part.removeHeader("Content-Transfer-Encoding");
     }
-
+    
     static void writeTo(MimePart part, OutputStream os, String[] ignoreList)
             throws IOException, MessagingException {
 
@@ -1641,7 +1640,7 @@ static void writeTo(MimePart part, OutputStream os, String[] ignoreList)
         } else {
             Map<String, Object> params = new HashMap<>();
             params.put("allowutf8", allowutf8);
-            los = StreamProvider.provider().outputLineStream(os, allowutf8);
+            los = part.getStreamProvider().outputLineStream(os, allowutf8);
         }
 
         // First, write out the header

api/src/main/java/jakarta/mail/internet/MimeMessage.java

@@ -29,7 +29,6 @@
 import jakarta.mail.Multipart;
 import jakarta.mail.Session;
 import jakarta.mail.util.LineOutputStream;
-import jakarta.mail.util.StreamProvider;
 
 import java.io.BufferedInputStream;
 import java.io.ByteArrayInputStream;
@@ -45,8 +44,6 @@
 import java.util.Enumeration;
 import java.util.List;
 import java.util.Properties;
-import java.util.ServiceConfigurationError;
-
 
 /**
  * This class represents a MIME style email message. It implements
@@ -245,7 +242,7 @@ public MimeMessage(MimeMessage source) throws MessagingException {
             strict = source.strict;
             source.writeTo(bos);
             bos.close();
-            try (InputStream bis = provider().inputSharedByteArray(bos.toByteArray())) {
+            try (InputStream bis = getStreamProvider().inputSharedByteArray(bos.toByteArray())) {
                 parse(bis);
             }
             saved = true;
@@ -1410,7 +1407,7 @@ protected InputStream getContentStream() throws MessagingException {
         if (contentStream != null)
             return ((SharedInputStream) contentStream).newStream(0, -1);
         if (content != null) {
-            return provider().inputSharedByteArray(content);
+            return getStreamProvider().inputSharedByteArray(content);
         }
         throw new MessagingException("No MimeMessage content");
     }
@@ -1917,7 +1914,7 @@ public void writeTo(OutputStream os, String[] ignoreList)
         // Else, the content is untouched, so we can just output it
         // First, write out the header
         Enumeration<String> hdrLines = getNonMatchingHeaderLines(ignoreList);
-        LineOutputStream los = provider().outputLineStream(os, allowutf8);
+        LineOutputStream los = getStreamProvider().outputLineStream(os, allowutf8);
         while (hdrLines.hasMoreElements())
             los.writeln(hdrLines.nextElement());
 

api/src/main/java/jakarta/mail/internet/MimeMultipart.java

@@ -520,7 +520,7 @@ public synchronized void writeTo(OutputStream os)
 
         String boundary = "--" +
                 (new ContentType(contentType)).getParameter("boundary");
-        LineOutputStream los = provider().outputLineStream(os, false);
+        LineOutputStream los = getStreamProvider().outputLineStream(os, false);
         // if there's a preamble, write it out
         if (preamble != null) {
             byte[] pb = MimeUtility.getBytes(preamble);
@@ -601,7 +601,7 @@ protected synchronized void parse() throws MessagingException {
 
         try {
             // Skip and save the preamble
-            LineInputStream lin = provider().inputLineStream(in, false);
+            LineInputStream lin = getStreamProvider().inputLineStream(in, false);
             StringBuilder preamblesb = null;
             String line;
             while ((line = lin.readLine()) != null) {

api/src/main/java/jakarta/mail/internet/PreencodedMimeBodyPart.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -78,7 +78,7 @@ public void writeTo(OutputStream os)
         if (os instanceof LineOutputStream) {
             los = (LineOutputStream) os;
         } else {
-            los = streamProvider.outputLineStream(os, false);
+            los = getStreamProvider().outputLineStream(os, false);
         }
 
         // First, write out the header