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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *  http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17
    18  package org.apache.any23.source;
    19
    20  import java.io.IOException;
    21  import java.io.InputStream;
    22
    23  /**
    24   * A source of input streams. Mostly intended for situations where opening of an input stream is to be delayed.
    25   *
    26   * @author Richard Cyganiak (richard@cyganiak.de)
    27   */
    28  public interface DocumentSource {
    29
    30      /**
    31       * Returns the input stream for accessing the content of the document.
    32       *
    33       * @return not <code>null</code> input stream for accessing document data.
    34       *
    35       * @throws IOException
    36       *             if there is an error opening the {@link org.apache.any23.source.DocumentSource}
    37       *             {@link java.io.InputStream}
    38       */
    39      InputStream openInputStream() throws IOException;
    40
    41      /**
    42       * @return a string describing the content type of the provided document.
    43       */
    44      public String getContentType();
    45
    46      /**
    47       * @return the size of the content length in bytes.
    48       */
    49      public long getContentLength();
    50
    51      /**
    52       * @return the actual, final, canonical IRI if redirects occur.
    53       */
    54      public String getDocumentIRI();
    55
    56      /**
    57       * A value of <i>false</i> indicates that the document resides remotely, and that multiple successive accesses to it
    58       * should be avoided by copying it to local storage. This can also be used for sources that do not support multiple
    59       * calls to {@link #openInputStream()}.
    60       *
    61       * @return true if the {@link org.apache.any23.source.DocumentSource} is cached locally.
    62       */
    63      public boolean isLocal();
    64  }