Helper ForeignProtocol

Jan Burse, created Sep 15. 2018
package jekdev.reference.system;
import jekpro.tools.call.InterpreterMessage;
import jekpro.tools.term.Knowledgebase;
import matula.util.system.ConnectionReader;
import matula.util.system.ConnectionWriter;
import java.io.Writer;
/**
* The foreign predicates for the module protocol.
* <p/>
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* otherwise agreed upon, XLOG Technologies GmbH makes no warranties
* regarding the provided information. XLOG Technologies GmbH assumes
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* provided by XLOG Technologies GmbH.
* <p/>
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* and patent rights in particular - are the sole property of XLOG
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* <p/>
* Reproduction is restricted to the whole unaltered document. Reproduction
* of the information is only allowed for non-commercial uses. Selling,
* giving away or letting of the execution of the library is prohibited.
* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
* <p/>
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* Only to be distributed with programs that add significant and primary
* functionality to the library. Not to be distributed with additional
* software intended to replace any components of the library.
* <p/>
* Trademarks
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*/
public class ForeignProtocol {
/**
* <p>Retrieve the protocol writer of a stream.</p>
*
* @param para The protocolable stream.
* @return The protocol writer or null.
*/
public static Object sysGetStreamProtocol(Object para)
throws InterpreterMessage {
if (para instanceof ConnectionReader) {
para = ((ConnectionReader) para).getUnbuf();
} else if (para instanceof ConnectionWriter) {
para = ((ConnectionWriter) para).getUnbuf();
}
Writer protocol;
if (para instanceof ProtocolReader) {
protocol = ((ProtocolReader) para).getProtocol();
} else if (para instanceof ProtocolWriter) {
protocol = ((ProtocolWriter) para).getProtocol();
} else {
throw new InterpreterMessage(
InterpreterMessage.permissionError("protocol", "stream", para));
}
return (protocol != null ? protocol : Knowledgebase.OP_NULL);
}
/**
* <p>Set the protocol writer of a stream.</p>
*
* @param para The protocolable stream.
* @param proterm The protocol writer or null.
* @throws InterpreterMessage Permission error
*/
public static void sysSetStreamProtocol(Object para, Object proterm)
throws InterpreterMessage {
Writer protocol;
if (proterm instanceof String && proterm.equals("null")) {
protocol = null;
} else if (proterm instanceof Writer) {
protocol = (Writer) proterm;
} else {
throw new InterpreterMessage(
InterpreterMessage.typeError("protocol", para));
}
if (para instanceof ConnectionReader) {
para = ((ConnectionReader) para).getUnbuf();
} else if (para instanceof ConnectionWriter) {
para = ((ConnectionWriter) para).getUnbuf();
}
if (para instanceof ProtocolReader) {
((ProtocolReader) para).setProtocol(protocol);
} else if (para instanceof ProtocolWriter) {
((ProtocolWriter) para).setProtocol(protocol);
} else {
throw new InterpreterMessage(
InterpreterMessage.permissionError("protocol", "stream", para));
}
}
}

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