plc4j/api/src/main/java/org/apache/plc4x/java/api/PlcConnection.java

/*
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
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specific language governing permissions and limitations
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*/
package org.apache.plc4x.java.api;

import org.apache.plc4x.java.api.exceptions.PlcConnectionException;
import org.apache.plc4x.java.api.exceptions.PlcInvalidFieldException;
import org.apache.plc4x.java.api.exceptions.PlcRuntimeException;
import org.apache.plc4x.java.api.exceptions.PlcUnsupportedOperationException;
import org.apache.plc4x.java.api.messages.PlcReadRequest;
import org.apache.plc4x.java.api.messages.PlcSubscriptionRequest;
import org.apache.plc4x.java.api.messages.PlcUnsubscriptionRequest;
import org.apache.plc4x.java.api.messages.PlcWriteRequest;
import org.apache.plc4x.java.api.metadata.PlcConnectionMetadata;
import org.apache.plc4x.java.api.model.PlcField;

import java.util.concurrent.CompletableFuture;

/**
 * Interface defining the most basic methods a PLC4X connection should support.
 * This generally handles the connection establishment itself and the parsing of
 * field address strings to the platform dependent PlcField instances.
 */
public interface PlcConnection extends AutoCloseable {

    /**
     * Establishes the connection to the remote PLC.
     * @throws PlcConnectionException if the connection attempt failed
     */
    void connect() throws PlcConnectionException;

    /**
     * Indicates if the connection is established to a remote PLC.
     * @return {@code true} if connected, {@code false} otherwise
     */
    boolean isConnected();

    /**
     * Closes the connection to the remote PLC.
     * @throws Exception if shutting down the connection failed
     */
    @Override
    void close() throws Exception;

    /**
     * Parse a fieldQuery for the given connection type.
     *
     * @throws PlcRuntimeException If the string cannot be parsed
     */
    default PlcField prepareField(String fieldQuery) throws PlcInvalidFieldException {
        throw new PlcRuntimeException("Parse method is not implemented for this connection / driver");
    }

    /**
     * Provides connection metadata.
     */
    PlcConnectionMetadata getMetadata();

    /**
     * Execute a ping query against a remote device to check the availability of the connection.
     *
     * @return CompletableFuture that is completed successfully (Void) or unsuccessfully with an PlcException.
     */
    CompletableFuture<Void> ping();

    /**
     * Obtain read request builder.
     * @throws PlcUnsupportedOperationException if the connection does not support reading
     */
    PlcReadRequest.Builder readRequestBuilder();

    /**
     * Obtain write request builder.
     * @throws PlcUnsupportedOperationException if the connection does not support writing
     */
    PlcWriteRequest.Builder writeRequestBuilder();

    /**
     * Obtain subscription request builder.
     * @throws PlcUnsupportedOperationException if the connection does not support subscription
     */
    PlcSubscriptionRequest.Builder subscriptionRequestBuilder();

    /**
     * Obtain unsubscription request builder.
     * @throws PlcUnsupportedOperationException if the connection does not support subscription
     */
    PlcUnsubscriptionRequest.Builder unsubscriptionRequestBuilder();

}