org.apache.parquet.io.SeekableInputStream Maven / Gradle / Ivy
/*
* 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.parquet.io;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.List;
import org.apache.parquet.bytes.ByteBufferAllocator;
/**
* {@code SeekableInputStream} is an interface with the methods needed by
* Parquet to read data from a file or Hadoop data stream.
*/
public abstract class SeekableInputStream extends InputStream {
/**
* Return the current position in the InputStream.
*
* @return current position in bytes from the start of the stream
* @throws IOException If the underlying stream throws IOException
*/
public abstract long getPos() throws IOException;
/**
* Seek to a new position in the InputStream.
*
* @param newPos the new position to seek to
* @throws IOException If the underlying stream throws IOException
*/
public abstract void seek(long newPos) throws IOException;
/**
* Read a byte array of data, from position 0 to the end of the array.
*
* This method is equivalent to {@code read(bytes, 0, bytes.length)}.
*
* This method will block until len bytes are available to copy into the
* array, or will throw {@link EOFException} if the stream ends before the
* array is full.
*
* @param bytes a byte array to fill with data from the stream
* @throws IOException If the underlying stream throws IOException
* @throws EOFException If the stream has fewer bytes left than are needed to
* fill the array, {@code bytes.length}
*/
public abstract void readFully(byte[] bytes) throws IOException;
/**
* Read {@code len} bytes of data into an array, at position {@code start}.
*
* This method will block until len bytes are available to copy into the
* array, or will throw {@link EOFException} if the stream ends before the
* array is full.
*
* @param bytes a byte array to fill with data from the stream
* @param start the starting position in the byte array for data
* @param len the length of bytes to read into the byte array
* @throws IOException If the underlying stream throws IOException
* @throws EOFException If the stream has fewer than {@code len} bytes left
*/
public abstract void readFully(byte[] bytes, int start, int len) throws IOException;
/**
* Read {@code buf.remaining()} bytes of data into a {@link ByteBuffer}.
*
* This method will copy available bytes into the buffer, reading at most
* {@code buf.remaining()} bytes. The number of bytes actually copied is
* returned by the method, or -1 is returned to signal that the end of the
* underlying stream has been reached.
*
* @param buf a byte buffer to fill with data from the stream
* @return the number of bytes read or -1 if the stream ended
* @throws IOException If the underlying stream throws IOException
*/
public abstract int read(ByteBuffer buf) throws IOException;
/**
* Read {@code buf.remaining()} bytes of data into a {@link ByteBuffer}.
*
* This method will block until {@code buf.remaining()} bytes are available
* to copy into the buffer, or will throw {@link EOFException} if the stream
* ends before the buffer is full.
*
* @param buf a byte buffer to fill with data from the stream
* @throws IOException If the underlying stream throws IOException
* @throws EOFException If the stream has fewer bytes left than are needed to
* fill the buffer, {@code buf.remaining()}
*/
public abstract void readFully(ByteBuffer buf) throws IOException;
/**
* Read a set of disjoint file ranges in a vectored manner.
*
* @param ranges a list of non-overlapping file ranges to read
* @param allocator the allocator to use for allocating ByteBuffers
* @throws UnsupportedOperationException if not available in this class/runtime (default)
* @throws EOFException if a range is past the known end of the file.
* @throws IOException any IO problem initiating the read operations.
* @throws IllegalArgumentException if there are overlapping ranges or
* a range element is invalid
*/
public void readVectored(List ranges, final ByteBufferAllocator allocator) throws IOException {
throw new UnsupportedOperationException("Vectored IO is not supported for " + this);
}
/**
* Is the {@link #readVectored(List, ByteBufferAllocator)} method available?
* @param allocator the allocator to use for allocating ByteBuffers
* @return True if the operation is considered available for this allocator in the hadoop runtime.
*/
public boolean readVectoredAvailable(final ByteBufferAllocator allocator) {
return false;
}
}