com.google.protobuf.LazyField Maven / Gradle / Ivy
// Protocol Buffers - Google's data interchange format
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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();
}
}
}