LazyField.java

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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
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// in the documentation and/or other materials provided with the
// distribution.
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package com.google.protobuf;
 
import java.util.Iterator;
import java.util.Map.Entry;
 
public class LazyField extends LazyFieldLite {
 
  private final MessageLite defaultInstance;
 
  public LazyField(
      MessageLite defaultInstance, ExtensionRegistryLite extensionRegistry, ByteString bytes) {
    super(extensionRegistry, bytes);
 
    this.defaultInstance = defaultInstance;
  }
 
  @Override
  public boolean containsDefaultInstance() {
    return super.containsDefaultInstance() || value == defaultInstance;
  }
 
  public MessageLite getValue() {
    return getValue(defaultInstance);
  }
 
  @Override
  public int hashCode() {
    return getValue().hashCode();
  }
 
  @Override
  public boolean equals(Object obj) {
    return getValue().equals(obj);
  }
 
  @Override
  public String toString() {
    return getValue().toString();
  }
 
  // ====================================================
 
  static class LazyEntry<K> implements Entry<K, Object> {
    private Entry<K, LazyField> entry;
 
    private LazyEntry(Entry<K, LazyField> entry) {
      this.entry = entry;
    }
 
    @Override
    public K getKey() {
      return entry.getKey();
    }
 
    @Override
    public Object getValue() {
      LazyField field = entry.getValue();
      if (field == null) {
        return null;
      }
      return field.getValue();
    }
 
    public LazyField getField() {
      return entry.getValue();
    }
 
    @Override
    public Object setValue(Object value) {
      if (!(value instanceof MessageLite)) {
        throw new IllegalArgumentException(
            "LazyField now only used for MessageSet, "
                + "and the value of MessageSet must be an instance of MessageLite");
      }
      return entry.getValue().setValue((MessageLite) value);
    }
  }
 
  static class LazyIterator<K> implements Iterator<Entry<K, Object>> {
    private Iterator<Entry<K, Object>> iterator;
 
    public LazyIterator(Iterator<Entry<K, Object>> iterator) {
      this.iterator = iterator;
    }
 
    @Override
    public boolean hasNext() {
      return iterator.hasNext();
    }
 
    @Override
    @SuppressWarnings("unchecked")
    public Entry<K, Object> next() {
      Entry<K, ?> entry = iterator.next();
      if (entry.getValue() instanceof LazyField) {
        return new LazyEntry<K>((Entry<K, LazyField>) entry);
      }
      return (Entry<K, Object>) entry;
    }
 
    @Override
    public void remove() {
      iterator.remove();
    }
  }
}