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