data/rfc8528-data-util/src/main/java/org/opendaylight/yangtools/rfc8528/data/util/MountPointNormalizedNodeWriter.java

   1 /*
   2  * Copyright (c) 2019 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.yangtools.rfc8528.data.util;
   9
  10 import static com.google.common.base.Preconditions.checkArgument;
  11 import static java.util.Objects.requireNonNull;
  12
  13 import com.google.common.annotations.Beta;
  14 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  15 import java.io.IOException;
  16 import org.eclipse.jdt.annotation.NonNull;
  17 import org.opendaylight.yangtools.rfc8528.data.api.MountPointNode;
  18 import org.opendaylight.yangtools.rfc8528.data.api.StreamWriterMountPointExtension;
  19 import org.opendaylight.yangtools.yang.data.api.schema.DataContainerChild;
  20 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  21 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
  22 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeWriter;
  23
  24 /**
  25  * A {@link MountPointNode}-aware counterpart to {@link NormalizedNodeWriter}. Based on the backing writer's capability
  26  * it either forwards or filters MountPointNodes.
  27  */
  28 @Beta
  29 public abstract class MountPointNormalizedNodeWriter extends NormalizedNodeWriter {
  30     private static final class Filtering extends MountPointNormalizedNodeWriter {
  31         Filtering(final NormalizedNodeStreamWriter writer) {
  32             super(writer);
  33         }
  34
  35         @Override
  36         void writeMountPoint(final MountPointNode node) {
  37             // No-op
  38         }
  39     }
  40
  41     private static final class Forwarding extends MountPointNormalizedNodeWriter {
  42         private final StreamWriterMountPointExtension mountWriter;
  43
  44         Forwarding(final NormalizedNodeStreamWriter writer, final StreamWriterMountPointExtension mountWriter) {
  45             super(writer);
  46             this.mountWriter = requireNonNull(mountWriter);
  47         }
  48
  49         @Override
  50         void writeMountPoint(final MountPointNode node) throws IOException {
  51             try (MountPointNormalizedNodeWriter writer = forStreamWriter(mountWriter.startMountPoint(
  52                     node.getIdentifier(), node.getMountPointContext()))) {
  53                 for (DataContainerChild child : node.body()) {
  54                     writer.write(child);
  55                 }
  56             }
  57         }
  58     }
  59
  60     MountPointNormalizedNodeWriter(final NormalizedNodeStreamWriter writer) {
  61         super(writer);
  62     }
  63
  64     public static @NonNull MountPointNormalizedNodeWriter forStreamWriter(final NormalizedNodeStreamWriter writer) {
  65         final StreamWriterMountPointExtension mountWriter = writer.getExtensions()
  66             .getInstance(StreamWriterMountPointExtension.class);
  67         return mountWriter == null ? new Filtering(writer) : new Forwarding(writer, mountWriter);
  68     }
  69
  70     public static @NonNull MountPointNormalizedNodeWriter filteringFor(final NormalizedNodeStreamWriter writer) {
  71         return new Filtering(writer);
  72     }
  73
  74     @SuppressFBWarnings(value = "NP_NULL_ON_SOME_PATH_FROM_RETURN_VALUE",
  75         justification = "SpotBugs does not grok checkArgument()")
  76     public static @NonNull MountPointNormalizedNodeWriter forwardingFor(final NormalizedNodeStreamWriter writer) {
  77         final StreamWriterMountPointExtension mountWriter = writer.getExtensions()
  78             .getInstance(StreamWriterMountPointExtension.class);
  79         checkArgument(mountWriter != null, "Writer %s does not support mount points", writer);
  80         return new Forwarding(writer, mountWriter);
  81     }
  82
  83     @Override
  84     protected final boolean wasProcessedAsCompositeNode(final NormalizedNode node) throws IOException {
  85         if (node instanceof MountPointNode) {
  86             writeMountPoint((MountPointNode) node);
  87             return true;
  88         }
  89         return super.wasProcessedAsCompositeNode(node);
  90     }
  91
  92     abstract void writeMountPoint(MountPointNode node) throws IOException;
  93 }