jnidzwetzki/bboxdb

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bboxdb-server/src/main/java/org/bboxdb/network/packets/response/HelloResponse.java

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/*******************************************************************************
 *
 *    Copyright (C) 2015-2022 the BBoxDB project
 *  
 *    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 org.bboxdb.network.packets.response;

import java.io.OutputStream;
import java.nio.ByteBuffer;

import org.bboxdb.commons.io.DataEncoderHelper;
import org.bboxdb.network.NetworkConst;
import org.bboxdb.network.NetworkPackageDecoder;
import org.bboxdb.network.capabilities.PeerCapabilities;
import org.bboxdb.network.packets.NetworkResponsePacket;
import org.bboxdb.network.packets.PacketEncodeException;

public class HelloResponse extends NetworkResponsePacket {
    
    /**
     * The supported protocol version
     */
    protected final int protocolVersion;
    
    /**
     * The peer capabilities (e.g. compression)
     */
    protected final PeerCapabilities peerCapabilities;
    
    
    public HelloResponse(final short sequenceNumber, final int protocolVersion, final PeerCapabilities peerCapabilities) {
        super(sequenceNumber);

        this.protocolVersion = protocolVersion;
        this.peerCapabilities = peerCapabilities;
    }
    
    @Override
    public long writeToOutputStream(final OutputStream outputStream) throws PacketEncodeException {
        
        try {
            final ByteBuffer bb = DataEncoderHelper.intToByteBuffer(protocolVersion);
            final byte[] peerCapabilitiesBytes = peerCapabilities.toByteArray();
            
            // Body length
            final long bodyLength = bb.capacity() + peerCapabilitiesBytes.length;
            final long headerLength = appendResponsePackageHeader(bodyLength, outputStream);

            // Write body
            outputStream.write(bb.array());
            outputStream.write(peerCapabilitiesBytes);
            
            return headerLength + bodyLength;
        } catch (Exception e) {
            throw new PacketEncodeException("Got exception while converting package into bytes", e);
        }            
    }

    /**
     * Decode the encoded package into a object
     * 
     * @param encodedPackage
     * @return
     * @throws PacketEncodeException 
     */
    public static HelloResponse decodePackage(final ByteBuffer encodedPackage) throws PacketEncodeException {        
        final short requestId = NetworkPackageDecoder.getRequestIDFromResponsePackage(encodedPackage);

        final boolean decodeResult = NetworkPackageDecoder.validateResponsePackageHeader(encodedPackage, NetworkConst.RESPONSE_TYPE_HELLO);

        if(decodeResult == false) {
            throw new PacketEncodeException("Unable to decode package");
        }
        
        final int protocolVersion = encodedPackage.getInt();
        final byte[] capabilityBytes = new byte[PeerCapabilities.CAPABILITY_BYTES];
        encodedPackage.get(capabilityBytes, 0, capabilityBytes.length);

        if(encodedPackage.remaining() != 0) {
            throw new PacketEncodeException("Some bytes are left after decoding: " + encodedPackage.remaining());
        }
        
        final PeerCapabilities peerCapabilities = new PeerCapabilities(capabilityBytes);
        peerCapabilities.freeze();
        
        return new HelloResponse(requestId, protocolVersion, peerCapabilities);
    }
    
    /**
     * Get the capabilities
     * @return
     */
    public PeerCapabilities getPeerCapabilities() {
        return peerCapabilities;
    }

    @Override
    public byte getPackageType() {
        return NetworkConst.RESPONSE_TYPE_HELLO;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime
                * result
                + ((peerCapabilities == null) ? 0 : peerCapabilities.hashCode());
        result = prime * result + protocolVersion;
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        HelloResponse other = (HelloResponse) obj;
        if (peerCapabilities == null) {
            if (other.peerCapabilities != null)
                return false;
        } else if (!peerCapabilities.equals(other.peerCapabilities))
            return false;
        if (protocolVersion != other.protocolVersion)
            return false;
        return true;
    }

}