restconf/restconf-openapi/src/main/java/org/opendaylight/restconf/openapi/impl/PathStream.java

   1 /*
   2  * Copyright (c) 2023 PANTHEON.tech s.r.o 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/epl-v10.html
   7  */
   8 package org.opendaylight.restconf.openapi.impl;
   9
  10 import java.io.BufferedReader;
  11 import java.io.ByteArrayInputStream;
  12 import java.io.IOException;
  13 import java.io.InputStream;
  14 import java.io.InputStreamReader;
  15 import java.io.Reader;
  16 import java.nio.ByteBuffer;
  17 import java.nio.channels.Channels;
  18 import java.nio.channels.ReadableByteChannel;
  19 import java.nio.charset.StandardCharsets;
  20 import java.util.Deque;
  21 import org.opendaylight.restconf.openapi.jaxrs.OpenApiBodyWriter;
  22 import org.opendaylight.restconf.openapi.model.OpenApiEntity;
  23 import org.opendaylight.restconf.openapi.model.PathEntity;
  24
  25 public final class PathStream extends InputStream {
  26     private final Deque<PathEntity> stack;
  27     private final OpenApiBodyWriter writer;
  28
  29     private Reader reader;
  30     private ReadableByteChannel channel;
  31
  32     public PathStream(final Deque<PathEntity> paths, final OpenApiBodyWriter writer) {
  33         this.stack = paths;
  34         this.writer = writer;
  35     }
  36
  37     @Override
  38     public int read() throws IOException {
  39         if (reader == null) {
  40             if (stack.isEmpty()) {
  41                 return -1;
  42             }
  43             reader = new BufferedReader(
  44                 new InputStreamReader(new ByteArrayInputStream(writeNextEntity(stack.pop())), StandardCharsets.UTF_8));
  45         }
  46
  47         var read = reader.read();
  48         while (read == -1) {
  49             if (stack.isEmpty()) {
  50                 return -1;
  51             }
  52             reader = new BufferedReader(
  53                 new InputStreamReader(new ByteArrayInputStream(writeNextEntity(stack.pop())), StandardCharsets.UTF_8));
  54             read = reader.read();
  55         }
  56
  57         return read;
  58     }
  59
  60     @Override
  61     public int read(final byte[] array, final int off, final int len) throws IOException {
  62         if (channel == null) {
  63             if (stack.isEmpty()) {
  64                 return -1;
  65             }
  66             channel = Channels.newChannel(new ByteArrayInputStream(writeNextEntity(stack.pop())));
  67         }
  68         var read = channel.read(ByteBuffer.wrap(array, off, len));
  69         while (read == -1) {
  70             if (stack.isEmpty()) {
  71                 return -1;
  72             }
  73             channel = Channels.newChannel(new ByteArrayInputStream(writeNextEntity(stack.pop())));
  74             read = channel.read(ByteBuffer.wrap(array, off, len));
  75         }
  76         return read;
  77     }
  78
  79     private byte[] writeNextEntity(final OpenApiEntity entity) throws IOException {
  80         writer.writeTo(entity, null, null, null, null, null, null);
  81         return writer.readFrom();
  82     }
  83 }