Java example source code file (StringDataContentHandler.java)

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Java - Java tags/keywords

activationdataflavor, awt, contenttype, datacontenthandler, datasource, datatransfer, illegalargumentexception, inputstreamreader, ioexception, object, outputstreamwriter, string, stringdatacontenthandler, text, unsupportedencodingexception

The StringDataContentHandler.java Java example source code

/*
 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.xml.internal.ws.encoding;

import javax.activation.ActivationDataFlavor;
import javax.activation.DataSource;
import javax.activation.DataContentHandler;
import java.awt.datatransfer.DataFlavor;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;

/**
 * JavaMail's data content handler for text/plain -->String
 */
public class StringDataContentHandler implements DataContentHandler {
    private static final ActivationDataFlavor myDF = new ActivationDataFlavor(
            java.lang.String.class, "text/plain", "Text String");

    protected ActivationDataFlavor getDF() {
        return myDF;
    }

    /**
     * Return the DataFlavors for this <code>DataContentHandler.
     *
     * @return The DataFlavors
     */
    public DataFlavor[] getTransferDataFlavors() {
        return new DataFlavor[]{getDF()};
    }

    /**
     * Return the Transfer Data of type DataFlavor from InputStream.
     *
     * @param df The DataFlavor
     * @param ds The DataSource corresponding to the data
     * @return String object
     */
    public Object getTransferData(DataFlavor df, DataSource ds)
            throws IOException {
        // use myDF.equals to be sure to get ActivationDataFlavor.equals,
        // which properly ignores Content-Type parameters in comparison
        if (getDF().equals(df))
            return getContent(ds);
        else
            return null;
    }

    public Object getContent(DataSource ds) throws IOException {
        String enc = null;
        InputStreamReader is;

        try {
            enc = getCharset(ds.getContentType());
            is = new InputStreamReader(ds.getInputStream(), enc);
        } catch (IllegalArgumentException iex) {
            /*
            * An unknown charset of the form ISO-XXX-XXX will cause
            * the JDK to throw an IllegalArgumentException.  The
            * JDK will attempt to create a classname using this string,
            * but valid classnames must not contain the character '-',
            * and this results in an IllegalArgumentException, rather than
            * the expected UnsupportedEncodingException.  Yikes.
            */
            throw new UnsupportedEncodingException(enc);
        }

        try {
            int pos = 0;
            int count;
            char buf[] = new char[1024];

            while ((count = is.read(buf, pos, buf.length - pos)) != -1) {
                pos += count;
                if (pos >= buf.length) {
                    int size = buf.length;
                    if (size < 256 * 1024)
                        size += size;
                    else
                        size += 256 * 1024;
                    char tbuf[] = new char[size];
                    System.arraycopy(buf, 0, tbuf, 0, pos);
                    buf = tbuf;
                }
            }
            return new String(buf, 0, pos);
        } finally {
            try {
                is.close();
            } catch (IOException ex) {
                // not much can be done
            }
        }
    }

    /**
     * Write the object to the output stream, using the specified MIME type.
     */
    public void writeTo(Object obj, String type, OutputStream os)
            throws IOException {
        if (!(obj instanceof String))
            throw new IOException("\"" + getDF().getMimeType() +
                    "\" DataContentHandler requires String object, " +
                    "was given object of type " + obj.getClass().toString());

        String enc = null;
        OutputStreamWriter osw;

        try {
            enc = getCharset(type);
            osw = new OutputStreamWriter(os, enc);
        } catch (IllegalArgumentException iex) {
            /*
            * An unknown charset of the form ISO-XXX-XXX will cause
            * the JDK to throw an IllegalArgumentException.  The
            * JDK will attempt to create a classname using this string,
            * but valid classnames must not contain the character '-',
            * and this results in an IllegalArgumentException, rather than
            * the expected UnsupportedEncodingException.  Yikes.
            */
            throw new UnsupportedEncodingException(enc);
        }

        String s = (String) obj;
        osw.write(s, 0, s.length());
        osw.flush();
    }

    private String getCharset(String type) {
        try {
            ContentType ct = new ContentType(type);
            String charset = ct.getParameter("charset");
            if (charset == null)
                // If the charset parameter is absent, use US-ASCII.
                charset = "us-ascii";

            return Charset.forName(charset).name();
            //return MimeUtility.javaCharset(charset);
        } catch (Exception ex) {
            return null;
        }
    }


}