yang/yang-model-util/src/main/java/org/opendaylight/yangtools/yang/model/util/repo/FilesystemSchemaCachingProvider.java

   1 package org.opendaylight.yangtools.yang.model.util.repo;
   2
   3 import java.io.File;
   4 import java.io.FileInputStream;
   5 import java.io.FileNotFoundException;
   6 import java.io.FileOutputStream;
   7 import java.io.IOException;
   8 import java.io.InputStream;
   9 import java.io.OutputStreamWriter;
  10 import java.io.StringBufferInputStream;
  11
  12 import com.google.common.base.Function;
  13 import com.google.common.base.Optional;
  14 import com.google.common.base.Preconditions;
  15
  16 public class FilesystemSchemaCachingProvider<I> extends AbstractCachingSchemaSourceProvider<I, InputStream> {
  17
  18     private final File storageDirectory;
  19     private final Function<I, String> transformationFunction;
  20
  21     public FilesystemSchemaCachingProvider(SchemaSourceProvider<I> delegate, File directory,
  22             Function<I, String> transformationFunction) {
  23         super(delegate);
  24         this.storageDirectory = directory;
  25         this.transformationFunction = transformationFunction;
  26     }
  27
  28     @Override
  29     protected synchronized Optional<InputStream> cacheSchemaSource(SourceIdentifier identifier, Optional<I> source) {
  30         File schemaFile = toFile(identifier);
  31         try {
  32             if(source.isPresent() && schemaFile.createNewFile()) {
  33                 try (
  34                         FileOutputStream outStream = new FileOutputStream(schemaFile);
  35                         OutputStreamWriter writer = new OutputStreamWriter(outStream);
  36                 ) {
  37                 writer.write(transformToString(source.get()));
  38                 writer.flush();
  39                 } catch (IOException e) {
  40
  41                 }
  42             }
  43         } catch (IOException e){
  44
  45         }
  46         return transformToStream(source);
  47     }
  48
  49     @SuppressWarnings("deprecation")
  50     private Optional<InputStream> transformToStream(Optional<I> source) {
  51         if(source.isPresent()) {
  52             return Optional.<InputStream>of(new StringBufferInputStream(transformToString(source.get())));
  53         }
  54         return Optional.absent();
  55     }
  56
  57     private String transformToString(I input) {
  58         return transformationFunction.apply(input);
  59     }
  60
  61     @Override
  62     protected Optional<InputStream> getCachedSchemaSource(SourceIdentifier identifier) {
  63         File inputFile = toFile(identifier);
  64         try {
  65             if (inputFile.exists() && inputFile.canRead()) {
  66                 InputStream stream = new FileInputStream(inputFile);
  67                 return Optional.of(stream);
  68             }
  69         } catch (FileNotFoundException e) {
  70             return Optional.absent();
  71         }
  72         return Optional.absent();
  73     }
  74
  75     private File toFile(SourceIdentifier identifier) {
  76         return new File(storageDirectory, identifier.toYangFilename());
  77     }
  78
  79
  80
  81     private static final Function<String, String> NOOP_TRANSFORMATION = new Function<String, String>() {
  82         @Override
  83         public String apply(String input) {
  84             return input;
  85         }
  86     };
  87
  88     public static FilesystemSchemaCachingProvider<String> createFromStringSourceProvider(
  89             SchemaSourceProvider<String> liveProvider, File directory) {
  90         Preconditions.checkNotNull(liveProvider);
  91         Preconditions.checkNotNull(directory);
  92         directory.mkdirs();
  93         return new FilesystemSchemaCachingProvider<String>(liveProvider, directory,NOOP_TRANSFORMATION);
  94     }
  95 }