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

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/eplv10.html
   7  */
   8 package org.opendaylight.yangtools.yang.model.util.repo;
   9
  10 import java.io.File;
  11 import java.io.FileInputStream;
  12 import java.io.FileNotFoundException;
  13 import java.io.FileOutputStream;
  14 import java.io.IOException;
  15 import java.io.InputStream;
  16 import java.io.OutputStreamWriter;
  17 import java.io.StringBufferInputStream;
  18
  19 import com.google.common.base.Function;
  20 import com.google.common.base.Optional;
  21 import com.google.common.base.Preconditions;
  22
  23 public class FilesystemSchemaCachingProvider<I> extends AbstractCachingSchemaSourceProvider<I, InputStream> {
  24
  25     private final File storageDirectory;
  26     private final Function<I, String> transformationFunction;
  27
  28     public FilesystemSchemaCachingProvider(AdvancedSchemaSourceProvider<I> delegate, File directory,
  29             Function<I, String> transformationFunction) {
  30         super(delegate);
  31         this.storageDirectory = directory;
  32         this.transformationFunction = transformationFunction;
  33     }
  34
  35     @Override
  36     protected synchronized Optional<InputStream> cacheSchemaSource(SourceIdentifier identifier, Optional<I> source) {
  37         File schemaFile = toFile(identifier);
  38         try {
  39             if (source.isPresent() && schemaFile.createNewFile()) {
  40                 try (FileOutputStream outStream = new FileOutputStream(schemaFile);
  41                         OutputStreamWriter writer = new OutputStreamWriter(outStream);) {
  42                     writer.write(transformToString(source.get()));
  43                     writer.flush();
  44                 } catch (IOException e) {
  45
  46                 }
  47             }
  48         } catch (IOException e) {
  49
  50         }
  51         return transformToStream(source);
  52     }
  53
  54     @SuppressWarnings("deprecation")
  55     private Optional<InputStream> transformToStream(Optional<I> source) {
  56         if (source.isPresent()) {
  57             return Optional.<InputStream> of(new StringBufferInputStream(transformToString(source.get())));
  58         }
  59         return Optional.absent();
  60     }
  61
  62     private String transformToString(I input) {
  63         return transformationFunction.apply(input);
  64     }
  65
  66     @Override
  67     protected Optional<InputStream> getCachedSchemaSource(SourceIdentifier identifier) {
  68         File inputFile = toFile(identifier);
  69         try {
  70             if (inputFile.exists() && inputFile.canRead()) {
  71                 InputStream stream = new FileInputStream(inputFile);
  72                 return Optional.of(stream);
  73             }
  74         } catch (FileNotFoundException e) {
  75             return Optional.absent();
  76         }
  77         return Optional.absent();
  78     }
  79
  80     private File toFile(SourceIdentifier identifier) {
  81         return new File(storageDirectory, identifier.toYangFilename());
  82     }
  83
  84     private static final Function<String, String> NOOP_TRANSFORMATION = new Function<String, String>() {
  85         @Override
  86         public String apply(String input) {
  87             return input;
  88         }
  89     };
  90
  91     public static FilesystemSchemaCachingProvider<String> createFromStringSourceProvider(
  92             SchemaSourceProvider<String> liveProvider, File directory) {
  93         Preconditions.checkNotNull(liveProvider);
  94         Preconditions.checkNotNull(directory);
  95         directory.mkdirs();
  96         return new FilesystemSchemaCachingProvider<String>(
  97                 SchemaSourceProviders.toAdvancedSchemaSourceProvider(liveProvider),//
  98                 directory, //
  99                 NOOP_TRANSFORMATION);
 100     }
 101 }