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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.writer;
    19
    20  import org.apache.any23.extractor.ExtractionContext;
    21  import org.eclipse.rdf4j.model.Resource;
    22  import org.eclipse.rdf4j.model.IRI;
    23  import org.eclipse.rdf4j.model.Value;
    24
    25  /**
    26   * Defines a document based triple handler.
    27   */
    28  public interface TripleHandler extends AutoCloseable {
    29
    30      void startDocument(IRI documentIRI) throws TripleHandlerException;
    31
    32      /**
    33       * Informs the handler that a new context has been established. Contexts are not guaranteed to receive any triples,
    34       * so they might be closed without any triple.
    35       *
    36       * @param context
    37       *            an instantiated {@link org.apache.any23.extractor.ExtractionContext}
    38       *
    39       * @throws TripleHandlerException
    40       *             if there is an errr opening the {@link org.apache.any23.extractor.ExtractionContext}
    41       */
    42      void openContext(ExtractionContext context) throws TripleHandlerException;
    43
    44      /**
    45       * Invoked with a currently open context, notifies the detection of a triple.
    46       *
    47       * @param s
    48       *            triple subject, cannot be <code>null</code>.
    49       * @param p
    50       *            triple predicate, cannot be <code>null</code>.
    51       * @param o
    52       *            triple object, cannot be <code>null</code>.
    53       * @param g
    54       *            triple graph, can be <code>null</code>.
    55       * @param context
    56       *            extraction context.
    57       *
    58       * @throws TripleHandlerException
    59       *             if there is an error receiving the triple.
    60       */
    61      void receiveTriple(Resource s, IRI p, Value o, IRI g, ExtractionContext context) throws TripleHandlerException;
    62
    63      /**
    64       * Invoked with a currently open context, notifies the detection of a namespace.
    65       *
    66       * @param prefix
    67       *            namespace prefix.
    68       * @param uri
    69       *            namespace <i>IRI</i>.
    70       * @param context
    71       *            namespace context.
    72       *
    73       * @throws TripleHandlerException
    74       *             if there is an error receiving the namespace.
    75       */
    76      void receiveNamespace(String prefix, String uri, ExtractionContext context) throws TripleHandlerException;
    77
    78      /**
    79       * Informs the handler that no more triples will come from a previously opened context. All contexts are guaranteed
    80       * to be closed before the final close(). The document context for each document is guaranteed to be closed after
    81       * all local contexts of that document.
    82       *
    83       * @param context
    84       *            the context to be closed.
    85       *
    86       * @throws TripleHandlerException
    87       *             if there is an error closing the {@link org.apache.any23.extractor.ExtractionContext}.
    88       */
    89      void closeContext(ExtractionContext context) throws TripleHandlerException;
    90
    91      /**
    92       * Informs the handler that the end of the document has been reached.
    93       *
    94       * @param documentIRI
    95       *            document IRI.
    96       *
    97       * @throws TripleHandlerException
    98       *             if there is an error ending the document.
    99       */
    100     void endDocument(IRI documentIRI) throws TripleHandlerException;
    101
    102     /**
    103      * Sets the length of the content to be processed.
    104      *
    105      * @param contentLength
    106      *            length of the content being processed.
    107      */
    108     void setContentLength(long contentLength);
    109
    110     /**
    111      * Will be called last and exactly once.
    112      *
    113      * @throws TripleHandlerException
    114      *             if there is an error closing the {@link org.apache.any23.writer.TripleHandler} implementation.
    115      */
    116     void close() throws TripleHandlerException;
    117
    118 }