Java example source code file (SourceSinkFactories.java)

This example Java source code file (SourceSinkFactories.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

annotation, bytesinkfactory, bytesourcefactory, charsinkfactory, charsourcefactory, file, filebytesinkfactory, filebytesourcefactory, filecharsinkfactory, filecharsourcefactory, filefactory, fileoutputstream, ioexception, log, logging, nio, override, string, util

The SourceSinkFactories.java Java example source code

/*
 * Copyright (C) 2012 The Guava Authors
 *
 * 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.google.common.io;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.io.SourceSinkFactory.ByteSinkFactory;
import static com.google.common.io.SourceSinkFactory.ByteSourceFactory;
import static com.google.common.io.SourceSinkFactory.CharSinkFactory;
import static com.google.common.io.SourceSinkFactory.CharSourceFactory;

import com.google.common.base.Charsets;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.nio.CharBuffer;
import java.util.Arrays;
import java.util.logging.Logger;

import javax.annotation.Nullable;

/**
 * {@link SourceSinkFactory} implementations.
 *
 * @author Colin Decker
 */
public class SourceSinkFactories {

  private SourceSinkFactories() {}

  public static CharSourceFactory stringCharSourceFactory() {
    return new StringSourceFactory();
  }

  public static ByteSourceFactory byteArraySourceFactory() {
    return new ByteArraySourceFactory();
  }

  public static ByteSourceFactory emptyByteSourceFactory() {
    return new EmptyByteSourceFactory();
  }

  public static CharSourceFactory emptyCharSourceFactory() {
    return new EmptyCharSourceFactory();
  }

  public static ByteSourceFactory fileByteSourceFactory() {
    return new FileByteSourceFactory();
  }

  public static ByteSinkFactory fileByteSinkFactory() {
    return new FileByteSinkFactory(null);
  }

  public static ByteSinkFactory appendingFileByteSinkFactory() {
    String initialString = IoTestCase.ASCII + IoTestCase.I18N;
    return new FileByteSinkFactory(initialString.getBytes(Charsets.UTF_8));
  }

  public static CharSourceFactory fileCharSourceFactory() {
    return new FileCharSourceFactory();
  }

  public static CharSinkFactory fileCharSinkFactory() {
    return new FileCharSinkFactory(null);
  }

  public static CharSinkFactory appendingFileCharSinkFactory() {
    String initialString = IoTestCase.ASCII + IoTestCase.I18N;
    return new FileCharSinkFactory(initialString);
  }

  public static ByteSourceFactory urlByteSourceFactory() {
    return new UrlByteSourceFactory();
  }

  public static CharSourceFactory urlCharSourceFactory() {
    return new UrlCharSourceFactory();
  }

  public static ByteSourceFactory asByteSourceFactory(final CharSourceFactory factory) {
    checkNotNull(factory);
    return new ByteSourceFactory() {
      @Override
      public ByteSource createSource(byte[] data) throws IOException {
        return factory.createSource(new String(data, Charsets.UTF_8))
            .asByteSource(Charsets.UTF_8);
      }

      @Override
      public byte[] getExpected(byte[] data) {
        return factory.getExpected(new String(data, Charsets.UTF_8)).getBytes(Charsets.UTF_8);
      }

      @Override
      public void tearDown() throws IOException {
        factory.tearDown();
      }
    };
  }

  public static CharSourceFactory asCharSourceFactory(final ByteSourceFactory factory) {
    checkNotNull(factory);
    return new CharSourceFactory() {
      @Override
      public CharSource createSource(String string) throws IOException {
        return factory.createSource(string.getBytes(Charsets.UTF_8))
            .asCharSource(Charsets.UTF_8);
      }

      @Override
      public String getExpected(String data) {
        return new String(factory.getExpected(data.getBytes(Charsets.UTF_8)), Charsets.UTF_8);
      }

      @Override
      public void tearDown() throws IOException {
        factory.tearDown();
      }
    };
  }

  public static CharSinkFactory asCharSinkFactory(final ByteSinkFactory factory) {
    checkNotNull(factory);
    return new CharSinkFactory() {
      @Override
      public CharSink createSink() throws IOException {
        return factory.createSink().asCharSink(Charsets.UTF_8);
      }

      @Override
      public String getSinkContents() throws IOException {
        return new String(factory.getSinkContents(), Charsets.UTF_8);
      }

      @Override
      public String getExpected(String data) {
        /*
         * Get what the byte sink factory would expect for no written bytes, then append expected
         * string to that.
         */
        byte[] factoryExpectedForNothing = factory.getExpected(new byte[0]);
        return new String(factoryExpectedForNothing, Charsets.UTF_8) + checkNotNull(data);
      }

      @Override
      public void tearDown() throws IOException {
        factory.tearDown();
      }
    };
  }

  public static ByteSourceFactory asSlicedByteSourceFactory(final ByteSourceFactory factory,
      final long off, final long len) {
    checkNotNull(factory);
    return new ByteSourceFactory() {
      @Override
      public ByteSource createSource(byte[] bytes) throws IOException {
        return factory.createSource(bytes).slice(off, len);
      }

      @Override
      public byte[] getExpected(byte[] bytes) {
        byte[] baseExpected = factory.getExpected(bytes);
        int startOffset = (int) Math.min(off, baseExpected.length);
        int actualLen = (int) Math.min(len, baseExpected.length - startOffset);
        return Arrays.copyOfRange(baseExpected, startOffset, startOffset + actualLen);
      }

      @Override
      public void tearDown() throws IOException {
        factory.tearDown();
      }
    };
  }

  private static class StringSourceFactory implements CharSourceFactory {

    @Override
    public CharSource createSource(String data) throws IOException {
      return CharSource.wrap(data);
    }

    @Override
    public String getExpected(String data) {
      return data;
    }

    @Override
    public void tearDown() throws IOException {
    }
  }

  private static class ByteArraySourceFactory implements ByteSourceFactory {

    @Override
    public ByteSource createSource(byte[] bytes) throws IOException {
      return ByteSource.wrap(bytes);
    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      return bytes;
    }

    @Override
    public void tearDown() throws IOException {
    }
  }

  private static class EmptyCharSourceFactory implements CharSourceFactory {

    @Override
    public CharSource createSource(String data) throws IOException {
      return CharSource.empty();
    }

    @Override
    public String getExpected(String data) {
      return "";
    }

    @Override
    public void tearDown() throws IOException {
    }
  }

  private static class EmptyByteSourceFactory implements ByteSourceFactory {

    @Override
    public ByteSource createSource(byte[] bytes) throws IOException {
      return ByteSource.empty();
    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      return new byte[0];
    }

    @Override
    public void tearDown() throws IOException {
    }
  }

  private abstract static class FileFactory {

    private static final Logger logger = Logger.getLogger(FileFactory.class.getName());

    private final ThreadLocal<File> fileThreadLocal = new ThreadLocal();

    protected File createFile() throws IOException {
      File file = File.createTempFile("SinkSourceFile", "txt");
      fileThreadLocal.set(file);
      return file;
    }

    protected File getFile() {
      return fileThreadLocal.get();
    }

    public final void tearDown() throws IOException {
      if (!fileThreadLocal.get().delete()) {
        logger.warning("Unable to delete file: " + fileThreadLocal.get());
      }
      fileThreadLocal.remove();
    }
  }

  private static class FileByteSourceFactory extends FileFactory implements ByteSourceFactory {

    @Override
    public ByteSource createSource(byte[] bytes) throws IOException {
      checkNotNull(bytes);
      File file = createFile();
      OutputStream out = new FileOutputStream(file);
      try {
        out.write(bytes);
      } finally {
        out.close();
      }
      return Files.asByteSource(file);
    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      return checkNotNull(bytes);
    }
  }

  private static class FileByteSinkFactory extends FileFactory implements ByteSinkFactory {

    private final byte[] initialBytes;

    private FileByteSinkFactory(@Nullable byte[] initialBytes) {
      this.initialBytes = initialBytes;
    }

    @Override
    public ByteSink createSink() throws IOException {
      File file = createFile();
      if (initialBytes != null) {
        FileOutputStream out = new FileOutputStream(file);
        try {
          out.write(initialBytes);
        } finally {
          out.close();
        }
        return Files.asByteSink(file, FileWriteMode.APPEND);
      }
      return Files.asByteSink(file);
    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      if (initialBytes == null) {
        return checkNotNull(bytes);
      } else {
        byte[] result = new byte[initialBytes.length + bytes.length];
        System.arraycopy(initialBytes, 0, result, 0, initialBytes.length);
        System.arraycopy(bytes, 0, result, initialBytes.length, bytes.length);
        return result;
      }
    }

    @Override
    public byte[] getSinkContents() throws IOException {
      File file = getFile();
      InputStream in = new FileInputStream(file);
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      byte[] buffer = new byte[100];
      int read;
      while ((read = in.read(buffer)) != -1) {
        out.write(buffer, 0, read);
      }
      return out.toByteArray();
    }
  }

  private static class FileCharSourceFactory extends FileFactory implements CharSourceFactory {

    @Override
    public CharSource createSource(String string) throws IOException {
      checkNotNull(string);
      File file = createFile();
      Writer writer = new OutputStreamWriter(new FileOutputStream(file), Charsets.UTF_8);
      try {
        writer.write(string);
      } finally {
        writer.close();
      }
      return Files.asCharSource(file, Charsets.UTF_8);
    }

    @Override
    public String getExpected(String string) {
      return checkNotNull(string);
    }
  }

  private static class FileCharSinkFactory extends FileFactory implements CharSinkFactory {

    private final String initialString;

    private FileCharSinkFactory(@Nullable String initialString) {
      this.initialString = initialString;
    }

    @Override
    public CharSink createSink() throws IOException {
      File file = createFile();
      if (initialString != null) {
        Writer writer = new OutputStreamWriter(new FileOutputStream(file), Charsets.UTF_8);
        try {
          writer.write(initialString);
        } finally {
          writer.close();
        }
        return Files.asCharSink(file, Charsets.UTF_8, FileWriteMode.APPEND);
      }
      return Files.asCharSink(file, Charsets.UTF_8);
    }

    @Override
    public String getExpected(String string) {
      checkNotNull(string);
      return initialString == null
          ? string
          : initialString + string;
    }

    @Override
    public String getSinkContents() throws IOException {
      File file = getFile();
      Reader reader = new InputStreamReader(new FileInputStream(file), Charsets.UTF_8);
      StringBuilder builder = new StringBuilder();
      CharBuffer buffer = CharBuffer.allocate(100);
      while (reader.read(buffer) != -1) {
        buffer.flip();
        builder.append(buffer);
        buffer.clear();
      }
      return builder.toString();
    }
  }

  private static class UrlByteSourceFactory extends FileByteSourceFactory {

    @SuppressWarnings("CheckReturnValue") // only using super.createSource to create a file
    @Override
    public ByteSource createSource(byte[] bytes) throws IOException {
      super.createSource(bytes);
      return Resources.asByteSource(getFile().toURI().toURL());
    }
  }

  private static class UrlCharSourceFactory extends FileCharSourceFactory {

    @SuppressWarnings("CheckReturnValue") // only using super.createSource to create a file
    @Override
    public CharSource createSource(String string) throws IOException {
      super.createSource(string); // just ignore returned CharSource
      return Resources.asCharSource(getFile().toURI().toURL(), Charsets.UTF_8);
    }
  }
}