/*
 * Copyright 2015 Ben Ashford
 *
 * 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 jresp.pool;

import jresp.Connection;
import jresp.ConnectionException;
import jresp.Responses;
import jresp.protocol.RespType;

import java.io.IOException;
import java.util.ArrayDeque;
import java.util.Deque;

/**
 * A connection used solely for commands that have a single response to each request
 */
public class SingleCommandConnection {
    private Connection connection;

    private Deque<Responses> responseQueue = new ArrayDeque<>();

    public SingleCommandConnection(Connection connection) throws IOException, ConnectionException {
        this.connection = connection;
        this.connection.start(resp -> {
            synchronized (responseQueue) {
                responseQueue.pop().responseReceived(resp);
            }
        });
    }

    public void write(RespType command, Responses responses) {
        synchronized (responseQueue) {
            responseQueue.add(responses);
            connection.write(command);
        }
    }
}

/*
 * Copyright 2015 Ben Ashford
 *
 * 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 jresp.pool;

import jresp.Connection;
import jresp.ConnectionException;
import jresp.Responses;
import jresp.protocol.RespType;

import java.io.IOException;
import java.util.ArrayDeque;
import java.util.Deque;

/**
 * A connection used solely for commands that have a single response to each request
 */
public class SingleCommandConnection {
    private Connection connection;

    private final Deque<Responses> responseQueue = new ArrayDeque<>();

    public SingleCommandConnection(Connection connection) throws IOException, ConnectionException {
        this.connection = connection;
        this.connection.start(resp -> {
            Responses respondTo = null;
            synchronized (responseQueue) {
                if (responseQueue.isEmpty()) {
                    throw new IllegalStateException("Got an unexpected response: " + resp);
                }
                respondTo = responseQueue.pop();
            }
            respondTo.responseReceived(resp);
        });
    }

    public void write(RespType command, Responses responses) {
        synchronized (responseQueue) {
            responseQueue.add(responses);
            connection.write(command);
        }
    }
}

Put a sharper-edge on a potential failure-case when requests and responses become out-of-sync.
Put a sharper-edge on a potential failure-case when requests and
responses become out-of-sync.
