InMemoryFileItem.java

/*******************************************************************************
 * Copyright (c) 2012-2016 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.everrest.core.impl.provider.ext;

import org.apache.commons.fileupload.FileItem;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Response;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

import static javax.ws.rs.core.MediaType.TEXT_PLAIN;

/**
 * Implementation of {@link FileItem} which allow store data in memory only
 * without access to file system. If size of item exceeds limit (initial
 * allocated buffer size) then {@link WebApplicationException} will be thrown.
 *
 * @author andrew00x
 */
class InMemoryFileItem implements FileItem {

    private static final byte[] EMPTY_DATA = new byte[0];

    private final String fileName;
    private final int    maxSize;

    private ByteArrayOutputStream byteArrayOutputStream;
    private FilterOutputStream    countingOutputStream;
    private String                contentType;
    private String                fieldName;
    private boolean               isFormField;

    InMemoryFileItem(String contentType, String fieldName, boolean isFormField, String fileName, int maxSize) {
        this.contentType = contentType;
        this.fieldName = fieldName;
        this.isFormField = isFormField;
        this.fileName = fileName;
        this.maxSize = maxSize;
    }

    @Override
    public void delete() {
        byteArrayOutputStream = null;
        countingOutputStream = null;
    }

    @Override
    public byte[] get() {
        if (byteArrayOutputStream == null) {
            return EMPTY_DATA;
        }
        return byteArrayOutputStream.toByteArray();
    }

    @Override
    public String getContentType() {
        return contentType;
    }

    @Override
    public String getFieldName() {
        return fieldName;
    }

    @Override
    public InputStream getInputStream() throws IOException {
        return new ByteArrayInputStream(get());
    }

    @Override
    public String getName() {
        return fileName;
    }

    @Override
    public OutputStream getOutputStream() {
        if (byteArrayOutputStream == null) {
            byteArrayOutputStream = new ByteArrayOutputStream(maxSize);
            countingOutputStream = new FilterOutputStream(byteArrayOutputStream) {
                private int bytesCounter = 0;

                @Override
                public void write(byte[] b, int off, int len) throws IOException {
                    ensureDoNotExceedMaxSize(len);
                    super.write(b, off, len);
                    bytesCounter += len;
                }

                @Override
                public void write(int b) throws IOException {
                    ensureDoNotExceedMaxSize(1);
                    super.write(b);
                    bytesCounter++;
                }

                private void ensureDoNotExceedMaxSize(int numBytesToWrite) {
                    int newSize = bytesCounter + numBytesToWrite;
                    if (newSize > maxSize) {
                        throw new WebApplicationException(Response.status(413)
                                                                  .entity(String.format("Item size is too large. Must not be over %d", maxSize))
                                                                  .type(TEXT_PLAIN).build());
                    }
                }
            };
        }
        return countingOutputStream;
    }

    @Override
    public long getSize() {
        return get().length;
    }

    @Override
    public String getString() {
        return new String(get());
    }

    @Override
    public String getString(String encoding) throws UnsupportedEncodingException {
        return new String(get(), encoding);
    }

    @Override
    public boolean isFormField() {
        return isFormField;
    }

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

    @Override
    public void setFieldName(String name) {
        this.fieldName = name;
    }

    @Override
    public void setFormField(boolean state) {
        isFormField = state;
    }

    @Override
    public void write(File file) throws Exception {
        throw new UnsupportedOperationException();
    }
}