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Java example source code file (AbstractDiskHttpData.java)

This example Java source code file (AbstractDiskHttpData.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

abstractdiskhttpdata, abstracthttpdata, bytebuffer, choose, empty_buffer, failed, filechannel, fileinputstream, fileoutputstream, ioexception, multiple, nio, nullpointerexception, override, string

The AbstractDiskHttpData.java Java example source code

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you 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.
 */
package io.netty.handler.codec.http.multipart;

import io.netty.buffer.ByteBuf;
import io.netty.handler.codec.http.HttpConstants;
import io.netty.util.internal.EmptyArrays;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;

import static io.netty.buffer.Unpooled.*;

/**
 * Abstract Disk HttpData implementation
 */
public abstract class AbstractDiskHttpData extends AbstractHttpData {

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(AbstractDiskHttpData.class);

    private File file;
    private boolean isRenamed;
    private FileChannel fileChannel;

    protected AbstractDiskHttpData(String name, Charset charset, long size) {
        super(name, charset, size);
    }

    /**
     *
     * @return the real DiskFilename (basename)
     */
    protected abstract String getDiskFilename();
    /**
     *
     * @return the default prefix
     */
    protected abstract String getPrefix();
    /**
     *
     * @return the default base Directory
     */
    protected abstract String getBaseDirectory();
    /**
     *
     * @return the default postfix
     */
    protected abstract String getPostfix();
    /**
     *
     * @return True if the file should be deleted on Exit by default
     */
    protected abstract boolean deleteOnExit();

    /**
     * @return a new Temp File from getDiskFilename(), default prefix, postfix and baseDirectory
     */
    private File tempFile() throws IOException {
        String newpostfix;
        String diskFilename = getDiskFilename();
        if (diskFilename != null) {
            newpostfix = '_' + diskFilename;
        } else {
            newpostfix = getPostfix();
        }
        File tmpFile;
        if (getBaseDirectory() == null) {
            // create a temporary file
            tmpFile = File.createTempFile(getPrefix(), newpostfix);
        } else {
            tmpFile = File.createTempFile(getPrefix(), newpostfix, new File(
                    getBaseDirectory()));
        }
        if (deleteOnExit()) {
            tmpFile.deleteOnExit();
        }
        return tmpFile;
    }

    @Override
    public void setContent(ByteBuf buffer) throws IOException {
        if (buffer == null) {
            throw new NullPointerException("buffer");
        }
        try {
            size = buffer.readableBytes();
            checkSize(size);
            if (definedSize > 0 && definedSize < size) {
                throw new IOException("Out of size: " + size + " > " + definedSize);
            }
            if (file == null) {
                file = tempFile();
            }
            if (buffer.readableBytes() == 0) {
                // empty file
                if (!file.createNewFile()) {
                    throw new IOException("file exists already: " + file);
                }
                return;
            }
            FileOutputStream outputStream = new FileOutputStream(file);
            try {
                FileChannel localfileChannel = outputStream.getChannel();
                ByteBuffer byteBuffer = buffer.nioBuffer();
                int written = 0;
                while (written < size) {
                    written += localfileChannel.write(byteBuffer);
                }
                buffer.readerIndex(buffer.readerIndex() + written);
                localfileChannel.force(false);
            } finally {
                outputStream.close();
            }
            setCompleted();
        } finally {
            // Release the buffer as it was retained before and we not need a reference to it at all
            // See https://github.com/netty/netty/issues/1516
            buffer.release();
        }
    }

    @Override
    public void addContent(ByteBuf buffer, boolean last)
            throws IOException {
        if (buffer != null) {
            try {
                int localsize = buffer.readableBytes();
                checkSize(size + localsize);
                if (definedSize > 0 && definedSize < size + localsize) {
                    throw new IOException("Out of size: " + (size + localsize) +
                            " > " + definedSize);
                }
                ByteBuffer byteBuffer = buffer.nioBufferCount() == 1 ? buffer.nioBuffer() : buffer.copy().nioBuffer();
                int written = 0;
                if (file == null) {
                    file = tempFile();
                }
                if (fileChannel == null) {
                    FileOutputStream outputStream = new FileOutputStream(file);
                    fileChannel = outputStream.getChannel();
                }
                while (written < localsize) {
                    written += fileChannel.write(byteBuffer);
                }
                size += localsize;
                buffer.readerIndex(buffer.readerIndex() + written);
            } finally {
                // Release the buffer as it was retained before and we not need a reference to it at all
                // See https://github.com/netty/netty/issues/1516
                buffer.release();
            }
        }
        if (last) {
            if (file == null) {
                file = tempFile();
            }
            if (fileChannel == null) {
                FileOutputStream outputStream = new FileOutputStream(file);
                fileChannel = outputStream.getChannel();
            }
            fileChannel.force(false);
            fileChannel.close();
            fileChannel = null;
            setCompleted();
        } else {
            if (buffer == null) {
                throw new NullPointerException("buffer");
            }
        }
    }

    @Override
    public void setContent(File file) throws IOException {
        if (this.file != null) {
            delete();
        }
        this.file = file;
        size = file.length();
        checkSize(size);
        isRenamed = true;
        setCompleted();
    }

    @Override
    public void setContent(InputStream inputStream) throws IOException {
        if (inputStream == null) {
            throw new NullPointerException("inputStream");
        }
        if (file != null) {
            delete();
        }
        file = tempFile();
        FileOutputStream outputStream = new FileOutputStream(file);
        int written = 0;
        try {
            FileChannel localfileChannel = outputStream.getChannel();
            byte[] bytes = new byte[4096 * 4];
            ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
            int read = inputStream.read(bytes);
            while (read > 0) {
                byteBuffer.position(read).flip();
                written += localfileChannel.write(byteBuffer);
                checkSize(written);
                read = inputStream.read(bytes);
            }
            localfileChannel.force(false);
        } finally {
            outputStream.close();
        }
        size = written;
        if (definedSize > 0 && definedSize < size) {
            if (!file.delete()) {
                logger.warn("Failed to delete: {}", file);
            }
            file = null;
            throw new IOException("Out of size: " + size + " > " + definedSize);
        }
        isRenamed = true;
        setCompleted();
    }

    @Override
    public void delete() {
        if (fileChannel != null) {
            try {
                fileChannel.force(false);
                fileChannel.close();
            } catch (IOException e) {
                logger.warn("Failed to close a file.", e);
            }
            fileChannel = null;
        }
        if (! isRenamed) {
            if (file != null && file.exists()) {
                if (!file.delete()) {
                    logger.warn("Failed to delete: {}", file);
                }
            }
            file = null;
        }
    }

    @Override
    public byte[] get() throws IOException {
        if (file == null) {
            return EmptyArrays.EMPTY_BYTES;
        }
        return readFrom(file);
    }

    @Override
    public ByteBuf getByteBuf() throws IOException {
        if (file == null) {
            return EMPTY_BUFFER;
        }
        byte[] array = readFrom(file);
        return wrappedBuffer(array);
    }

    @Override
    public ByteBuf getChunk(int length) throws IOException {
        if (file == null || length == 0) {
            return EMPTY_BUFFER;
        }
        if (fileChannel == null) {
            FileInputStream inputStream = new FileInputStream(file);
            fileChannel = inputStream.getChannel();
        }
        int read = 0;
        ByteBuffer byteBuffer = ByteBuffer.allocate(length);
        while (read < length) {
            int readnow = fileChannel.read(byteBuffer);
            if (readnow == -1) {
                fileChannel.close();
                fileChannel = null;
                break;
            } else {
                read += readnow;
            }
        }
        if (read == 0) {
            return EMPTY_BUFFER;
        }
        byteBuffer.flip();
        ByteBuf buffer = wrappedBuffer(byteBuffer);
        buffer.readerIndex(0);
        buffer.writerIndex(read);
        return buffer;
    }

    @Override
    public String getString() throws IOException {
        return getString(HttpConstants.DEFAULT_CHARSET);
    }

    @Override
    public String getString(Charset encoding) throws IOException {
        if (file == null) {
            return "";
        }
        if (encoding == null) {
            byte[] array = readFrom(file);
            return new String(array, HttpConstants.DEFAULT_CHARSET.name());
        }
        byte[] array = readFrom(file);
        return new String(array, encoding.name());
    }

    @Override
    public boolean isInMemory() {
        return false;
    }

    @Override
    public boolean renameTo(File dest) throws IOException {
        if (dest == null) {
            throw new NullPointerException("dest");
        }
        if (file == null) {
            throw new IOException("No file defined so cannot be renamed");
        }
        if (!file.renameTo(dest)) {
            // must copy
            IOException exception = null;
            FileInputStream inputStream = null;
            FileOutputStream outputStream = null;
            long chunkSize = 8196;
            long position = 0;
            try {
                inputStream = new FileInputStream(file);
                outputStream = new FileOutputStream(dest);
                FileChannel in = inputStream.getChannel();
                FileChannel out = outputStream.getChannel();
                while (position < size) {
                    if (chunkSize < size - position) {
                        chunkSize = size - position;
                    }
                    position += in.transferTo(position, chunkSize , out);
                }
            } catch (IOException e) {
                exception = e;
            } finally {
                if (inputStream != null) {
                    try {
                        inputStream.close();
                    } catch (IOException e) {
                        if (exception == null) { // Choose to report the first exception
                            exception = e;
                        } else {
                            logger.warn("Multiple exceptions detected, the following will be suppressed {}", e);
                        }
                    }
                }
                if (outputStream != null) {
                    try {
                        outputStream.close();
                    } catch (IOException e) {
                        if (exception == null) { // Choose to report the first exception
                            exception = e;
                        } else {
                            logger.warn("Multiple exceptions detected, the following will be suppressed {}", e);
                        }
                    }
                }
            }
            if (exception != null) {
                throw exception;
            }
            if (position == size) {
                if (!file.delete()) {
                    logger.warn("Failed to delete: {}", file);
                }
                file = dest;
                isRenamed = true;
                return true;
            } else {
                if (!dest.delete()) {
                    logger.warn("Failed to delete: {}", dest);
                }
                return false;
            }
        }
        file = dest;
        isRenamed = true;
        return true;
    }

    /**
     * Utility function
     * @return the array of bytes
     */
    private static byte[] readFrom(File src) throws IOException {
        long srcsize = src.length();
        if (srcsize > Integer.MAX_VALUE) {
            throw new IllegalArgumentException(
                    "File too big to be loaded in memory");
        }
        FileInputStream inputStream = new FileInputStream(src);
        byte[] array = new byte[(int) srcsize];
        try {
            FileChannel fileChannel = inputStream.getChannel();
            ByteBuffer byteBuffer = ByteBuffer.wrap(array);
            int read = 0;
            while (read < srcsize) {
                read += fileChannel.read(byteBuffer);
            }
        } finally {
            inputStream.close();
        }
        return array;
    }

    @Override
    public File getFile() throws IOException {
        return file;
    }

    @Override
    public HttpData touch() {
        return this;
    }

    @Override
    public HttpData touch(Object hint) {
        return this;
    }
}

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