com.clearspring.analytics.stream.membership.DataOutputBuffer Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of stream-lib Show documentation
A library for summarizing data in streams for which it is infeasible to store all events
The newest version!
/**
 * 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
 n * "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 com.clearspring.analytics.stream.membership;

import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataOutputStream;
import java.io.IOException;

import java.util.Arrays;


/**
 * An implementation of the DataOutputStream interface. This class is completely thread
 * unsafe.
 */
public class DataOutputBuffer extends DataOutputStream {

    private static class Buffer extends ByteArrayOutputStream {

        public byte[] getData() {
            return Arrays.copyOf(buf, getLength());
            //return buf;
        }

        public int getLength() {
            return count;
        }

        public void reset() {
            count = 0;
        }

        public void write(DataInput in, int len) throws IOException {
            int newcount = count + len;
            if (newcount > buf.length) {
                byte newbuf[] = new byte[Math.max(buf.length << 1, newcount)];
                System.arraycopy(buf, 0, newbuf, 0, count);
                buf = newbuf;
            }
            in.readFully(buf, count, len);
            count = newcount;
        }
    }

    private Buffer buffer;

    /**
     * Constructs a new empty buffer.
     */
    public DataOutputBuffer() {
        this(new Buffer());
    }

    private DataOutputBuffer(Buffer buffer) {
        super(buffer);
        this.buffer = buffer;
    }

    /**
     * Returns the current contents of the buffer. Data is only valid to
     * {@link #getLength()}.
     */
    public byte[] getData() {
        return buffer.getData();
    }

    /**
     * Returns the length of the valid data currently in the buffer.
     */
    public int getLength() {
        return buffer.getLength();
    }

    /**
     * Resets the buffer to empty.
     */
    public DataOutputBuffer reset() {
        this.written = 0;
        buffer.reset();
        return this;
    }

    /**
     * Writes bytes from a DataInput directly into the buffer.
     */
    public void write(DataInput in, int length) throws IOException {
        buffer.write(in, length);
    }
}