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 *
 * 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.qpid.test.framework;

import java.util.List;

/**
 * A Circuit is the basic test unit against which test cases are to be written. A circuit consists of two 'ends', an
 * instigating 'publisher' end and a more passive 'receivers' end.
 *
 * <p/>Once created, the life-cycle of a circuit may be controlled by {@link #start()}ing it, or {@link #close()}ing it.
 * Once started, the circuit is ready to send messages over. Once closed the circuit can no longer be used.
 *
 * <p/>The state of the circuit may be taken with the {@link #check()} method, and asserted against by the
 * {@link #applyAssertions(java.util.List)} method.
 *
 * <p/>There is a default test procedure which may be performed against the circuit. The outline of this procedure is:
 *
 * <p/><pre>
 * Start the circuit.
 * Send test messages.
 * Request a status report.
 * Assert conditions on the publishing end of the circuit.
 * Assert conditions on the receiving end of the circuit.
 * Close the circuit.
 * Pass with no failed assertions or fail with a list of failed assertions.
 * </pre>
 *
 * <p/><table id="crc"><caption>CRC Card</caption>
 * <tr><th> Responsibilities
 * <tr><td> Supply the publishing and receiving ends of a test messaging circuit.
 * <tr><td> Start the circuit running.
 * <tr><td> Close the circuit down.
 * <tr><td> Take a reading of the circuits state.
 * <tr><td> Apply assertions against the circuits state.
 * <tr><td> Send test messages over the circuit.
 * <tr><td> Perform the default test procedue on the circuit.
 * </table>
 */
public interface Circuit
{
    /**
     * Gets the interface on the publishing end of the circuit.
     *
     * @return The publishing end of the circuit.
     */
    public Publisher getPublisher();

    /**
     * Gets the interface on the receiving end of the circuit.
     *
     * @return The receiving end of the circuit.
     */
    public Receiver getReceiver();

    /**
     * Connects and starts the circuit. After this method is called the circuit is ready to send messages.
     */
    public void start();

    /**
     * Checks the test circuit. The effect of this is to gather the circuits state, for both ends of the circuit,
     * into a report, against which assertions may be checked.
     */
    public void check();

    /**
     * Closes the circuit. All associated resources are closed.
     */
    public void close();

    /**
     * Applied a list of assertions against the test circuit. The {@link #check()} method should be called before doing
     * this, to ensure that the circuit has gathered its state into a report to assert against.
     *
     * @param assertions The list of assertions to apply to the circuit.
     *
     * @return Any assertions that failed.
     */
    public List<Assertion> applyAssertions(List<Assertion> assertions);

    /**
     * Runs the default test procedure against the circuit, and checks that all of the specified assertions hold.
     *
     * @param numMessages The number of messages to send using the default test procedure.
     * @param assertions  The list of assertions to apply.
     *
     * @return Any assertions that failed.
     */
    public List<Assertion> test(int numMessages, List<Assertion> assertions);
}