/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.lucene.store;
import java.io.Closeable;
import java.io.IOException;
/** Abstract base class for output to a file in a Directory. A random-access
* output stream. Used for all Lucene index output operations.
* <p>{@code IndexOutput} may only be used from one thread, because it is not
* thread safe (it keeps internal state like file position).
* @see Directory
* @see IndexInput
*/
public abstract class IndexOutput extends DataOutput implements Closeable {
/** Full description of this output, e.g. which class such as {@code FSIndexOutput}, and the full path to the file */
private final String resourceDescription;
/** Just the name part from {@code resourceDescription} */
private final String name;
/** Sole constructor. resourceDescription should be non-null, opaque string
* describing this resource; it's returned from {@link #toString}. */
protected IndexOutput(String resourceDescription, String name) {
if (resourceDescription == null) {
throw new IllegalArgumentException("resourceDescription must not be null");
}
this.resourceDescription = resourceDescription;
this.name = name;
}
/** Returns the name used to create this {@code IndexOutput}. This is especially useful when using
* {@link Directory#createTempOutput}. */
// TODO: can we somehow use this as the default resource description or something?
public String getName() {
return name;
}
/** Closes this stream to further operations. */
@Override
public abstract void close() throws IOException;
/** Returns the current position in this file, where the next write will
* occur.
*/
public abstract long getFilePointer();
/** Returns the current checksum of bytes written so far */
public abstract long getChecksum() throws IOException;
@Override
public String toString() {
return resourceDescription;
}
}