content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.shiro.lang.util;
  
  import java.io.File;
  import java.io.InputStream;
  
  /**
   * A {@code ByteSource} wraps a byte array and provides additional encoding operations.  Most users will find the
   * {@link Util} inner class sufficient to construct ByteSource instances.
   *
   * @since 1.0
   */
  public interface ByteSource {
  
      /**
       * Returns the wrapped byte array.
       *
       * @return the wrapped byte array.
       */
      byte[] getBytes();
  
      /**
       * Returns the <a href="http://en.wikipedia.org/wiki/Hexadecimal">Hex</a>-formatted String representation of the
       * underlying wrapped byte array.
       *
       * @return the <a href="http://en.wikipedia.org/wiki/Hexadecimal">Hex</a>-formatted String representation of the
       *         underlying wrapped byte array.
       */
      String toHex();
  
      /**
       * Returns the <a href="http://en.wikipedia.org/wiki/Base64">Base 64</a>-formatted String representation of the
       * underlying wrapped byte array.
       *
       * @return the <a href="http://en.wikipedia.org/wiki/Base64">Base 64</a>-formatted String representation of the
       *         underlying wrapped byte array.
       */
      String toBase64();
  
      /**
       * Returns {@code true} if the underlying wrapped byte array is null or empty (zero length), {@code false}
       * otherwise.
       *
       * @return {@code true} if the underlying wrapped byte array is null or empty (zero length), {@code false}
       *         otherwise.
       * @since 1.2
       */
      boolean isEmpty();
  
      /**
       * Utility class that can construct ByteSource instances.  This is slightly nicer than needing to know the
       * {@code ByteSource} implementation class to use.
       *
       * @since 1.2
       */
      public static final class Util {
  
          /**
           * Returns a new {@code ByteSource} instance representing the specified byte array.
           *
           * @param bytes the bytes to represent as a {@code ByteSource} instance.
           * @return a new {@code ByteSource} instance representing the specified byte array.
           */
          public static ByteSource bytes(byte[] bytes) {
              return new SimpleByteSource(bytes);
          }
  
          /**
           * Returns a new {@code ByteSource} instance representing the specified character array's bytes.  The byte
           * array is obtained assuming {@code UTF-8} encoding.
           *
           * @param chars the character array to represent as a {@code ByteSource} instance.
           * @return a new {@code ByteSource} instance representing the specified character array's bytes.
           */
          public static ByteSource bytes(char[] chars) {
              return new SimpleByteSource(chars);
          }
  
          /**
           * Returns a new {@code ByteSource} instance representing the specified string's bytes.  The byte
           * array is obtained assuming {@code UTF-8} encoding.
           *
           * @param string the string to represent as a {@code ByteSource} instance.
           * @return a new {@code ByteSource} instance representing the specified string's bytes.
           */
          public static ByteSource bytes(String string) {
              return new SimpleByteSource(string);
          }
  
          /**
           * Returns a new {@code ByteSource} instance representing the specified ByteSource.
           *
           * @param source the ByteSource to represent as a new {@code ByteSource} instance.
           * @return a new {@code ByteSource} instance representing the specified ByteSource.
           */
          public static ByteSource bytes(ByteSource source) {
              return new SimpleByteSource(source);
          }
  
          /**
           * Returns a new {@code ByteSource} instance representing the specified File's bytes.
           *
           * @param file the file to represent as a {@code ByteSource} instance.
           * @return a new {@code ByteSource} instance representing the specified File's bytes.
           */
          public static ByteSource bytes(File file) {
              return new SimpleByteSource(file);
          }
  
          /**
           * Returns a new {@code ByteSource} instance representing the specified InputStream's bytes.
           *
           * @param stream the InputStream to represent as a {@code ByteSource} instance.
           * @return a new {@code ByteSource} instance representing the specified InputStream's bytes.
           */
          public static ByteSource bytes(InputStream stream) {
              return new SimpleByteSource(stream);
          }
  
          /**
           * Returns {@code true} if the specified object can be easily represented as a {@code ByteSource} using
           * the {@link ByteSource.Util}'s default heuristics, {@code false} otherwise.
           * <p/>
           * This implementation merely returns {@link SimpleByteSource}.{@link SimpleByteSource#isCompatible(Object) isCompatible(source)}.
           *
           * @param source the object to test to see if it can be easily converted to ByteSource instances using default
           *               heuristics.
           * @return {@code true} if the specified object can be easily represented as a {@code ByteSource} using
           *         the {@link ByteSource.Util}'s default heuristics, {@code false} otherwise.
           */
          public static boolean isCompatible(Object source) {
              return SimpleByteSource.isCompatible(source);
          }
  
          /**
           * Returns a {@code ByteSource} instance representing the specified byte source argument.  If the argument
           * <em>cannot</em> be easily converted to bytes (as is indicated by the {@link #isCompatible(Object)} JavaDoc),
           * this method will throw an {@link IllegalArgumentException}.
           *
           * @param source the byte-backed instance that should be represented as a {@code ByteSource} instance.
           * @return a {@code ByteSource} instance representing the specified byte source argument.
           * @throws IllegalArgumentException if the argument <em>cannot</em> be easily converted to bytes
           *                                  (as indicated by the {@link #isCompatible(Object)} JavaDoc)
           */
          public static ByteSource bytes(Object source) throws IllegalArgumentException {
              if (source == null) {
                  return null;
              }
              if (!isCompatible(source)) {
                  String msg = "Unable to heuristically acquire bytes for object of type [" +
                          source.getClass().getName() + "].  If this type is indeed a byte-backed data type, you might " +
                          "want to write your own ByteSource implementation to extract its bytes explicitly.";
                  throw new IllegalArgumentException(msg);
              }
              if (source instanceof byte[]) {
                  return bytes((byte[]) source);
              } else if (source instanceof ByteSource) {
                  return (ByteSource) source;
              } else if (source instanceof char[]) {
                  return bytes((char[]) source);
              } else if (source instanceof String) {
                  return bytes((String) source);
              } else if (source instanceof File) {
                  return bytes((File) source);
              } else if (source instanceof InputStream) {
                  return bytes((InputStream) source);
              } else {
                  throw new IllegalStateException("Encountered unexpected byte source.  This is a bug - please notify " +
                          "the Shiro developer list asap (the isCompatible implementation does not reflect this " +
                          "method's implementation).");
              }
          }
      }
  }
  