Home | History | Annotate | Download | only in mime4j 
      1 /****************************************************************
      2  * Licensed to the Apache Software Foundation (ASF) under one   *
      3  * or more contributor license agreements.  See the NOTICE file *
      4  * distributed with this work for additional information        *
      5  * regarding copyright ownership.  The ASF licenses this file   *
      6  * to you under the Apache License, Version 2.0 (the            *
      7  * "License"); you may not use this file except in compliance   *
      8  * with the License.  You may obtain a copy of the License at   *
      9  *                                                              *
     10  *   http://www.apache.org/licenses/LICENSE-2.0                 *
     11  *                                                              *
     12  * Unless required by applicable law or agreed to in writing,   *
     13  * software distributed under the License is distributed on an  *
     14  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
     15  * KIND, either express or implied.  See the License for the    *
     16  * specific language governing permissions and limitations      *
     17  * under the License.                                           *
     18  ****************************************************************/
     19 
     20 package org.apache.james.mime4j;
     21 
     22 import org.apache.james.mime4j.decoder.Base64InputStream;
     23 import org.apache.james.mime4j.decoder.QuotedPrintableInputStream;
     24 import org.apache.james.mime4j.field.Field;
     25 import org.apache.james.mime4j.message.Header;
     26 
     27 import java.io.InputStream;
     28 import java.io.IOException;
     29 
     30 /**
     31  * Abstract implementation of ContentHandler that automates common
     32  * tasks. Currently performs header parsing and applies content-transfer
     33  * decoding to body parts.
     34  *
     35  *
     36  */
     37 public abstract class SimpleContentHandler extends  AbstractContentHandler {
     38 
     39     /**
     40      * Called after headers are parsed.
     41      */
     42     public abstract void headers(Header header);
     43 
     44     /**
     45      * Called when the body of a discrete (non-multipart) entity is encountered.
     46 
     47      * @param bd encapsulates the values (either read from the
     48      *        message stream or, if not present, determined implictly
     49      *        as described in the
     50      *        MIME rfc:s) of the <code>Content-Type</code> and
     51      *        <code>Content-Transfer-Encoding</code> header fields.
     52      * @param is the contents of the body. Base64 or quoted-printable
     53      *        decoding will be applied transparently.
     54      * @throws IOException should be thrown on I/O errors.
     55      */
     56     public abstract void bodyDecoded(BodyDescriptor bd, InputStream is) throws IOException;
     57 
     58 
     59     /* Implement introduced callbacks. */
     60 
     61     private Header currHeader;
     62 
     63     /**
     64      * @see org.apache.james.mime4j.AbstractContentHandler#startHeader()
     65      */
     66     public final void startHeader() {
     67         currHeader = new Header();
     68     }
     69 
     70     /**
     71      * @see org.apache.james.mime4j.AbstractContentHandler#field(java.lang.String)
     72      */
     73     public final void field(String fieldData) {
     74         currHeader.addField(Field.parse(fieldData));
     75     }
     76 
     77     /**
     78      * @see org.apache.james.mime4j.AbstractContentHandler#endHeader()
     79      */
     80     public final void endHeader() {
     81         Header tmp = currHeader;
     82         currHeader = null;
     83         headers(tmp);
     84     }
     85 
     86     /**
     87      * @see org.apache.james.mime4j.AbstractContentHandler#body(org.apache.james.mime4j.BodyDescriptor, java.io.InputStream)
     88      */
     89     public final void body(BodyDescriptor bd, InputStream is) throws IOException {
     90         if (bd.isBase64Encoded()) {
     91             bodyDecoded(bd, new Base64InputStream(is));
     92         }
     93         else if (bd.isQuotedPrintableEncoded()) {
     94             bodyDecoded(bd, new QuotedPrintableInputStream(is));
     95         }
     96         else {
     97             bodyDecoded(bd, is);
     98         }
     99     }
    100 }
    101