spi/ContentProvider.java

   1 package org.argeo.api.acr.spi;
   2
   3 import java.util.Iterator;
   4 import java.util.Spliterator;
   5
   6 import javax.xml.namespace.NamespaceContext;
   7
   8 import org.argeo.api.acr.Content;
   9 import org.argeo.api.acr.ContentNotFoundException;
  10 import org.argeo.api.acr.ContentSession;
  11 import org.argeo.api.acr.search.BasicSearch;
  12
  13 /**
  14  * A prover of {@link Content}, which can be mounted in a
  15  * {@link ProvidedRepository}.
  16  */
  17 public interface ContentProvider extends NamespaceContext {
  18
  19         /**
  20          * Return the content at this path, relative to the mount path.
  21          *
  22          * @return the content at this relative path, never <code>null</code>
  23          * @throws ContentNotFoundException if there is no content at this relative path
  24          */
  25         ProvidedContent get(ProvidedSession session, String relativePath) throws ContentNotFoundException;
  26
  27         /**
  28          * Whether a content exist at his relative path. The default implementation call
  29          * {@link #get(ProvidedSession, String)} and check whether a
  30          * {@link ContentNotFoundException} is thrown or not. It should be overridden as
  31          * soon as there is a mechanism to check existence before actually getting the
  32          * content.
  33          */
  34         default boolean exists(ProvidedSession session, String relativePath) {
  35                 try {
  36                         get(session, relativePath);
  37                         return true;
  38                 } catch (ContentNotFoundException e) {
  39                         return false;
  40                 }
  41         }
  42
  43         /** The absolute path where this provider is mounted. */
  44         String getMountPath();
  45
  46         /**
  47          * Search content within this provider. The default implementation throws an
  48          * {@link UnsupportedOperationException}.
  49          */
  50         default Spliterator<Content> search(ProvidedSession session, BasicSearch search, String relPath) {
  51                 throw new UnsupportedOperationException();
  52         }
  53
  54         /*
  55          * EDITION
  56          */
  57         /** Switch this content (and its subtree) to editing mode. */
  58         default void openForEdit(ProvidedSession session, String relativePath) {
  59                 throw new UnsupportedOperationException();
  60         }
  61
  62         /** Switch this content (and its subtree) to frozen mode. */
  63         default void freeze(ProvidedSession session, String relativePath) {
  64                 throw new UnsupportedOperationException();
  65         }
  66
  67         /** Whether this content (and its subtree) are in editing mode. */
  68         default boolean isOpenForEdit(ProvidedSession session, String relativePath) {
  69                 throw new UnsupportedOperationException();
  70         }
  71
  72         /**
  73          * Called when an edition cycle is completed. Does nothing by default.
  74          *
  75          * @see ContentSession#edit(java.util.function.Consumer)
  76          */
  77         default void persist(ProvidedSession session) {
  78         }
  79
  80         /*
  81          * NAMESPACE CONTEXT
  82          */
  83         @Override
  84         default String getPrefix(String namespaceURI) {
  85                 Iterator<String> prefixes = getPrefixes(namespaceURI);
  86                 return prefixes.hasNext() ? prefixes.next() : null;
  87         }
  88
  89 }