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

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Apache License
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Java Source Code

/*******************************************************************************
 * Copyright 2014 Sergey Tarasevich// w  ww . j  a v a  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.ext;

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

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

/**
 * Disk cache based on "Least-Recently Used" principle. Adapter pattern, adapts
 * {@link com.nostra13.universalimageloader.cache.disc.impl.ext.DiskLruCache DiskLruCache} to
 * {@link com.nostra13.universalimageloader.cache.disc.DiskCache DiskCache}
 *
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * @see FileNameGenerator
 * @since 1.9.2
 */
public class LruDiskCache 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 ERROR_ARG_NEGATIVE = " argument must be positive number";

  protected DiskLruCache cache;
  private 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
   * @param fileNameGenerator {@linkplain com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator
   *                          Name generator} for cached files. Generated names must match the regex
   *                          <strong>[a-z0-9_-]{1,64}</strong>
   * @param cacheMaxSize      Max cache size in bytes. <b>0</b> means cache size is unlimited.
   * @throws IOException if cache can't be initialized (e.g. "No space left on device")
   */
  public LruDiskCache(File cacheDir, FileNameGenerator fileNameGenerator, long cacheMaxSize) throws IOException {
    this(cacheDir, null, fileNameGenerator, cacheMaxSize, 0);
  }

  /**
   * @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. Generated names must match the regex
   *                          <strong>[a-z0-9_-]{1,64}</strong>
   * @param cacheMaxSize      Max cache size in bytes. <b>0</b> means cache size is unlimited.
   * @param cacheMaxFileCount Max file count in cache. <b>0</b> means file count is unlimited.
   * @throws IOException if cache can't be initialized (e.g. "No space left on device")
   */
  public LruDiskCache(File cacheDir, File reserveCacheDir, FileNameGenerator fileNameGenerator, long cacheMaxSize,
      int cacheMaxFileCount) throws IOException {
    if (cacheDir == null) {
      throw new IllegalArgumentException("cacheDir" + ERROR_ARG_NULL);
    }
    if (cacheMaxSize < 0) {
      throw new IllegalArgumentException("cacheMaxSize" + ERROR_ARG_NEGATIVE);
    }
    if (cacheMaxFileCount < 0) {
      throw new IllegalArgumentException("cacheMaxFileCount" + ERROR_ARG_NEGATIVE);
    }
    if (fileNameGenerator == null) {
      throw new IllegalArgumentException("fileNameGenerator" + ERROR_ARG_NULL);
    }

    if (cacheMaxSize == 0) {
      cacheMaxSize = Long.MAX_VALUE;
    }
    if (cacheMaxFileCount == 0) {
      cacheMaxFileCount = Integer.MAX_VALUE;
    }

    this.reserveCacheDir = reserveCacheDir;
    this.fileNameGenerator = fileNameGenerator;
    initCache(cacheDir, reserveCacheDir, cacheMaxSize, cacheMaxFileCount);
  }

  private void initCache(File cacheDir, File reserveCacheDir, long cacheMaxSize, int cacheMaxFileCount)
      throws IOException {
    try {
      cache = DiskLruCache.open(cacheDir, 1, 1, cacheMaxSize, cacheMaxFileCount);
    } catch (IOException e) {
      L.e(e);
      if (reserveCacheDir != null) {
        initCache(reserveCacheDir, null, cacheMaxSize, cacheMaxFileCount);
      }
      if (cache == null) {
        throw e; //new RuntimeException("Can't initialize disk cache", e);
      }
    }
  }

  @Override
  public File getDirectory() {
    return cache.getDirectory();
  }

  @Override
  public File get(String imageUri) {
    DiskLruCache.Snapshot snapshot = null;
    try {
      snapshot = cache.get(getKey(imageUri));
      return snapshot == null ? null : snapshot.getFile(0);
    } catch (IOException e) {
      L.e(e);
      return null;
    } finally {
      if (snapshot != null) {
        snapshot.close();
      }
    }
  }

  @Override
  public boolean save(String imageUri, InputStream imageStream, IoUtils.CopyListener listener) throws IOException {
    DiskLruCache.Editor editor = cache.edit(getKey(imageUri));
    if (editor == null) {
      return false;
    }

    OutputStream os = new BufferedOutputStream(editor.newOutputStream(0), bufferSize);
    boolean copied = false;
    try {
      copied = IoUtils.copyStream(imageStream, os, listener, bufferSize);
    } finally {
      IoUtils.closeSilently(os);
      if (copied) {
        editor.commit();
      } else {
        editor.abort();
      }
    }
    return copied;
  }

  @Override
  public boolean save(String imageUri, Bitmap bitmap) throws IOException {
    DiskLruCache.Editor editor = cache.edit(getKey(imageUri));
    if (editor == null) {
      return false;
    }

    OutputStream os = new BufferedOutputStream(editor.newOutputStream(0), bufferSize);
    boolean savedSuccessfully = false;
    try {
      savedSuccessfully = bitmap.compress(compressFormat, compressQuality, os);
    } finally {
      IoUtils.closeSilently(os);
    }
    if (savedSuccessfully) {
      editor.commit();
    } else {
      editor.abort();
    }
    return savedSuccessfully;
  }

  @Override
  public boolean remove(String imageUri) {
    try {
      return cache.remove(getKey(imageUri));
    } catch (IOException e) {
      L.e(e);
      return false;
    }
  }

  @Override
  public void close() {
    try {
      cache.close();
    } catch (IOException e) {
      L.e(e);
    }
    cache = null;
  }

  @Override
  public void clear() {
    try {
      cache.delete();
    } catch (IOException e) {
      L.e(e);
    }
    try {
      initCache(cache.getDirectory(), reserveCacheDir, cache.getMaxSize(), cache.getMaxFileCount());
    } catch (IOException e) {
      L.e(e);
    }
  }

  private String getKey(String imageUri) {
    return fileNameGenerator.generate(imageUri);
  }

  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;
  }
}
Java Source Code List
