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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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package com.google.protobuf;

import java.util.Iterator;
import java.util.Map.Entry;

/**
 * LazyField encapsulates the logic of lazily parsing message fields. It stores the message in a
 * ByteString initially and then parses it on-demand.
 *
 * 

Most methods are implemented in {@link LazyFieldLite} but this class can contain a * default instance of the message to provide {@code hashCode()}, {@code equals()}, and {@code * toString()}. * * @author [email protected] (Xiang Li) */ public class LazyField extends LazyFieldLite { /** * Carry a message's default instance which is used by {@code hashCode()}, {@code equals()}, and * {@code toString()}. */ 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(); } // ==================================================== /** * LazyEntry and LazyIterator are used to encapsulate the LazyField, when users iterate all fields * from FieldSet. */ static class LazyEntry implements Entry { private Entry entry; private LazyEntry(Entry 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 implements Iterator> { private Iterator> iterator; public LazyIterator(Iterator> iterator) { this.iterator = iterator; } @Override public boolean hasNext() { return iterator.hasNext(); } @Override @SuppressWarnings("unchecked") public Entry next() { Entry entry = iterator.next(); if (entry.getValue() instanceof LazyField) { return new LazyEntry((Entry) entry); } return (Entry) entry; } @Override public void remove() { iterator.remove(); } } }





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