Android Open Source - masterdetail-j2objc-swift Flat File Detail Service

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License

The source code is released under:

Apache License

Java Source Code

/*
 * Copyright 2014 Kirk C. Vogen//from w w w  .j  a va 2  s .co m
 *
 * 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 masterdetail.service;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import masterdetail.model.DetailEntry;

/**
 * A service implementation that uses flat files for persisting items.
 */
public class FlatFileDetailService implements DetailService {

  private StorageService storageService;
  
  public FlatFileDetailService(StorageService storageService) {
    this.storageService = storageService;
  }

  private File getStorageDir() {
    File storageDir = new File(this.storageService.getStoragePath(), "list");
    storageDir.mkdirs();
    
    return storageDir;
  }
  
  private File getFile(int filenum) {
    return new File(getStorageDir(), String.valueOf(filenum));
  }

  @Override
  public DetailEntry create() {
    List<Integer> ids = findAllIds();

    int newId = 0;
    int lastId = newId;

    for (int id : ids) {
      newId = id + 1;

      if (lastId + 1 < newId) {
        newId = lastId;
        break;
      }

      lastId = newId;
    }

    createEmptyFile(newId);

    DetailEntry list = new DetailEntry();
    list.setId(newId);
    return list;
  }

  private void createEmptyFile(int newId) {
    File newFile = new File(getStorageDir(), String.valueOf(newId));
    
    try {
      newFile.createNewFile();
    } catch (IOException e) {
      throw new RuntimeException("Unable to create item with ID: " + newId, e);
    }
  }

  @Override
  public void delete(int id) {
    getFile(id).delete();
  }

  @Override
  public void delete(DetailEntry detailEntry) {
    delete(detailEntry.getId());
  }

  @Override
  public void update(DetailEntry detailEntry) {
    FileWriter out = null;
    
    try {
      out = new FileWriter(getFile(detailEntry.getId()));
      writeContent(detailEntry.getTitle(), detailEntry.getWords(), out);
    } catch (IOException e) {
      throw new RuntimeException("Unable to write updates to item with ID: "
          + detailEntry.getId(), e);
    } finally {
      closeQuietly(out);
    }
  }
  
  private void writeContent(String title, List<String> words, Writer out) throws IOException {
    BufferedWriter buf = new BufferedWriter(out);
    
    buf.write(title);
    buf.newLine();
    
    for (String word : words) {
      buf.write(word);
      buf.newLine();
    }
    
    buf.flush();
  }

  @Override
  public DetailEntry find(int id) {
    FileReader in = null;
    DetailEntry list = null;
    
    File file = getFile(id);
    if (!file.exists())
    {
      return null;
    }
    
    try  {
      in = new FileReader(file);
      list = readContent(in);
    } catch (IOException e) {
      throw new RuntimeException("Unable to read the item with ID: " + id, e);
    } finally {
      closeQuietly(in);
    }
    
    list.setId(id);
    return list;
  }
  
  private static void closeQuietly(Reader in)  {
    if (in != null)
    {
      try {
        in.close();
      } catch (IOException e) {
        // There is nothing more that can be done
      }
    }
  }
  
  private static void closeQuietly(Writer out)  {
    if (out != null) {
      try {
        out.close();
      } catch (IOException e) {
        // There is nothing more that can be done
      }
    }
  }

  private static DetailEntry readContent(Reader in) throws IOException {
    ArrayList<String> words = new ArrayList<String> ();
    DetailEntry list = new DetailEntry();
    
    BufferedReader buf = new BufferedReader(in);
    list.setTitle(buf.readLine());
    
    String line;
    while ((line = buf.readLine()) != null)  {
      words.add(line);
    }
    
    list.setWords(words);
    return list;
  }

  @Override
  public Boolean exists(int id) {
    return getFile(id).exists();
  }

  @Override
  public List<DetailEntry> findAll() {
    ArrayList<DetailEntry> detailEntries = new ArrayList<DetailEntry> ();
    
    for (int id : findAllIds()) {
      detailEntries.add(find(id));
    }

    return detailEntries;
  }

  private List<Integer> findAllIds() {
    ArrayList<Integer> ids = new ArrayList<Integer> ();
    
    for (File file : getStorageDir().listFiles()) {
      ids.add(Integer.valueOf(file.getName()));
    }

    Collections.sort(ids);
    
    return ids;
  }
}

Java Source Code List

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