net.openhft.chronicle.wire.NoDocumentContext Maven / Gradle / Ivy
/*
* Copyright 2016-2020 chronicle.software
*
* https://chronicle.software
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.openhft.chronicle.wire;
/**
* An enumeration implementation of the {@link DocumentContext} interface.
* This context represents a non-existent or uninitialized document context,
* hence all its methods return default or null values.
*
* This can be useful as a sentinel value or placeholder to avoid null checks in code
* that works with document contexts. Using `NoDocumentContext.INSTANCE` denotes
* a guaranteed uninitialized state for a document context.
*/
public enum NoDocumentContext implements DocumentContext {
/** The singleton instance of the NoDocumentContext */
INSTANCE;
@Override
public boolean isMetaData() {
return false;
}
@Override
public boolean isPresent() {
return false;
}
@Override
public boolean isData() {
return false;
}
@Override
public Wire wire() {
return null;
}
@Override
public int sourceId() {
return -1;
}
@Override
public long index() {
return Long.MIN_VALUE;
}
@Override
public boolean isNotComplete() {
return false;
}
@Override
public void close() {
// Do nothing
}
@Override
public void reset() {
close();
}
}