br.com.objectos.comuns.web.upload.UploadRequestApacheCommons Maven / Gradle / Ivy

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/*
 * Copyright 2012 Objectos, Fábrica de Software LTDA.
 *
 * Licensed 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 br.com.objectos.comuns.web.upload;

import java.io.IOException;
import java.util.Iterator;

import javax.servlet.http.HttpServletRequest;

import com.google.common.base.Preconditions;
import com.google.common.collect.AbstractIterator;

import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

/**
 * @author [email protected] (Marcio Endo)
 */
class UploadRequestApacheCommons implements UploadRequest {

  private final TheIterable iterable;

  public UploadRequestApacheCommons(HttpServletRequest request) {
    this.iterable = new TheIterable(request);
  }

  @Override
  public Iterable getPotentialFiles() {
    return iterable;
  }

  @Override
  public UploadedForm getUploadedForm() {
    return iterable.getForm();
  }

  private static class TheIterable implements Iterable {

    private final HttpServletRequest request;

    private final MapUploadedForm form = new MapUploadedForm();

    private boolean formReady = false;

    public TheIterable(HttpServletRequest request) {
      this.request = request;
    }

    @Override
    public Iterator iterator() {
      return new TheIterator();
    }

    public MapUploadedForm getForm() {
      Preconditions.checkState(formReady,
          "You should iterate through the files before calling this method.");
      return form;
    }

    private class TheIterator extends AbstractIterator {

      private final FileItemIterator delegate;

      private final PotentialFile firstAndOnly;

      private boolean stopNow = false;

      public TheIterator() {
        ServletFileUpload upload = new ServletFileUpload();

        FileItemIterator delegate = null;
        PotentialFile firstAndOnly = null;

        try {
          delegate = upload.getItemIterator(request);

        } catch (FileUploadException e) {
          firstAndOnly = new PotentialFileFailed(e);

        } catch (IOException e) {
          firstAndOnly = new PotentialFileFailed(e);

        }

        this.delegate = delegate;
        this.firstAndOnly = firstAndOnly;
      }

      @Override
      protected PotentialFile computeNext() {
        if (stopNow) {
          return theEnd();
        }

        if (firstAndOnly != null) {
          stopNow = true;
          return firstAndOnly;
        }

        PotentialFile next = null;

        try {
          next = getNext();

        } catch (FileUploadException e) {
          next = new PotentialFileFailed(e);

        } catch (IOException e) {
          next = new PotentialFileFailed(e);

        }

        return next != null ? next : theEnd();
      }

      private PotentialFile theEnd() {
        formReady = true;
        return endOfData();
      }

      private PotentialFile getNext() throws FileUploadException, IOException {
        PotentialFile next = null;

        while (delegate.hasNext()) {
          FileItemStream stream = delegate.next();

          if (!stream.isFormField()) {
            UploadedFile file = new UploadedFileApacheCommons(stream);
            next = new PotentialFileSucceeded(file);
            break;
          } else {
            UploadedFormFieldApacheCommons field = new UploadedFormFieldApacheCommons(stream);
            form.add(field);
          }
        }

        return next;
      }
    }

  }

}