Android Open Source - Android-Universal-Image-Loader Base Disk Cache

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License

The source code is released under:

Apache License

Java Source Code

/*******************************************************************************
 * Copyright 2011-2014 Sergey Tarasevich
 */* w w  w. j a va  2s.  c  o  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 com.nostra13.universalimageloader.cache.disc.impl;

import android.graphics.Bitmap;
import com.nostra13.universalimageloader.cache.disc.DiskCache;
import com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator;
import com.nostra13.universalimageloader.core.DefaultConfigurationFactory;
import com.nostra13.universalimageloader.utils.IoUtils;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Base disk cache.
 *
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * @see FileNameGenerator
 * @since 1.0.0
 */
public abstract class BaseDiskCache implements DiskCache {
  /** {@value */
  public static final int DEFAULT_BUFFER_SIZE = 32 * 1024; // 32 Kb
  /** {@value */
  public static final Bitmap.CompressFormat DEFAULT_COMPRESS_FORMAT = Bitmap.CompressFormat.PNG;
  /** {@value */
  public static final int DEFAULT_COMPRESS_QUALITY = 100;

  private static final String ERROR_ARG_NULL = " argument must be not null";
  private static final String TEMP_IMAGE_POSTFIX = ".tmp";

  protected final File cacheDir;
  protected final File reserveCacheDir;

  protected final FileNameGenerator fileNameGenerator;

  protected int bufferSize = DEFAULT_BUFFER_SIZE;

  protected Bitmap.CompressFormat compressFormat = DEFAULT_COMPRESS_FORMAT;
  protected int compressQuality = DEFAULT_COMPRESS_QUALITY;

  /** @param cacheDir Directory for file caching */
  public BaseDiskCache(File cacheDir) {
    this(cacheDir, null);
  }

  /**
   * @param cacheDir        Directory for file caching
   * @param reserveCacheDir null-ok; Reserve directory for file caching. It's used when the primary directory isn't available.
   */
  public BaseDiskCache(File cacheDir, File reserveCacheDir) {
    this(cacheDir, reserveCacheDir, DefaultConfigurationFactory.createFileNameGenerator());
  }

  /**
   * @param cacheDir          Directory for file caching
   * @param reserveCacheDir   null-ok; Reserve directory for file caching. It's used when the primary directory isn't available.
   * @param fileNameGenerator {@linkplain com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator
   *                          Name generator} for cached files
   */
  public BaseDiskCache(File cacheDir, File reserveCacheDir, FileNameGenerator fileNameGenerator) {
    if (cacheDir == null) {
      throw new IllegalArgumentException("cacheDir" + ERROR_ARG_NULL);
    }
    if (fileNameGenerator == null) {
      throw new IllegalArgumentException("fileNameGenerator" + ERROR_ARG_NULL);
    }

    this.cacheDir = cacheDir;
    this.reserveCacheDir = reserveCacheDir;
    this.fileNameGenerator = fileNameGenerator;
  }

  @Override
  public File getDirectory() {
    return cacheDir;
  }

  @Override
  public File get(String imageUri) {
    return getFile(imageUri);
  }

  @Override
  public boolean save(String imageUri, InputStream imageStream, IoUtils.CopyListener listener) throws IOException {
    File imageFile = getFile(imageUri);
    File tmpFile = new File(imageFile.getAbsolutePath() + TEMP_IMAGE_POSTFIX);
    boolean loaded = false;
    try {
      OutputStream os = new BufferedOutputStream(new FileOutputStream(tmpFile), bufferSize);
      try {
        loaded = IoUtils.copyStream(imageStream, os, listener, bufferSize);
      } finally {
        IoUtils.closeSilently(os);
      }
    } finally {
      if (loaded && !tmpFile.renameTo(imageFile)) {
        loaded = false;
      }
      if (!loaded) {
        tmpFile.delete();
      }
    }
    return loaded;
  }

  @Override
  public boolean save(String imageUri, Bitmap bitmap) throws IOException {
    File imageFile = getFile(imageUri);
    File tmpFile = new File(imageFile.getAbsolutePath() + TEMP_IMAGE_POSTFIX);
    OutputStream os = new BufferedOutputStream(new FileOutputStream(tmpFile), bufferSize);
    boolean savedSuccessfully = false;
    try {
      savedSuccessfully = bitmap.compress(compressFormat, compressQuality, os);
    } finally {
      IoUtils.closeSilently(os);
      if (savedSuccessfully && !tmpFile.renameTo(imageFile)) {
        savedSuccessfully = false;
      }
      if (!savedSuccessfully) {
        tmpFile.delete();
      }
    }
    bitmap.recycle();
    return savedSuccessfully;
  }

  @Override
  public boolean remove(String imageUri) {
    return getFile(imageUri).delete();
  }

  @Override
  public void close() {
    // Nothing to do
  }

  @Override
  public void clear() {
    File[] files = cacheDir.listFiles();
    if (files != null) {
      for (File f : files) {
        f.delete();
      }
    }
  }

  /** Returns file object (not null) for incoming image URI. File object can reference to non-existing file. */
  protected File getFile(String imageUri) {
    String fileName = fileNameGenerator.generate(imageUri);
    File dir = cacheDir;
    if (!cacheDir.exists() && !cacheDir.mkdirs()) {
      if (reserveCacheDir != null && (reserveCacheDir.exists() || reserveCacheDir.mkdirs())) {
        dir = reserveCacheDir;
      }
    }
    return new File(dir, fileName);
  }

  public void setBufferSize(int bufferSize) {
    this.bufferSize = bufferSize;
  }

  public void setCompressFormat(Bitmap.CompressFormat compressFormat) {
    this.compressFormat = compressFormat;
  }

  public void setCompressQuality(int compressQuality) {
    this.compressQuality = compressQuality;
  }
}

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