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/*
* Copyright 2011-Present, Redis Ltd. and Contributors
* All rights reserved.
*
* Licensed under the MIT License.
*
* This file contains contributions from third-party contributors
* 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
*
* https://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 io.lettuce.core.output;
import java.nio.ByteBuffer;
import io.lettuce.core.codec.RedisCodec;
import io.lettuce.core.internal.LettuceAssert;
/**
* Base class for Redis command outputs.
*
*
* Provides common decode methods and parsing functionality for output handling. Template methods that accept response values
* throw {@link UnsupportedOperationException} unless overridden by the concrete implementation.
*
* Command outputs may accumulate their state until a command is finished or emit partial results during the decode process.
* Output implementations that wish to emit partial results can implement {@link StreamingOutput} push individual output
* elements to a {@link StreamingOutput.Subscriber}.
*
* @param Key type.
* @param Value type.
* @param Output type.
* @author Will Glozer
* @author Mark Paluch
*/
public abstract class CommandOutput {
protected final RedisCodec codec;
protected T output;
protected String error;
/**
* Initialize a new instance that encodes and decodes keys and values using the supplied codec.
*
* @param codec Codec used to encode/decode keys and values, must not be {@code null}.
* @param output Initial value of output.
*/
public CommandOutput(RedisCodec codec, T output) {
LettuceAssert.notNull(codec, "RedisCodec must not be null");
this.codec = codec;
this.output = output;
}
/**
* Get the command output.
*
* @return The command output.
*/
public T get() {
return output;
}
/**
* Update the command output with a sequence of bytes, or {@code null}. Concrete {@link CommandOutput} implementations must
* override this method to decode {@code bulk}/bytes response values.
*
* @param bytes The command output, or null.
*/
public void set(ByteBuffer bytes) {
throw new UnsupportedOperationException(getClass().getName() + " does not support set(ByteBuffer)");
}
/**
* Update the command output with a sequence of bytes, or {@code null} representing a simple string. Concrete
* {@link CommandOutput} implementations must override this method to decode {@code single}/bytes response values.
*
* @param bytes The command output, or null.
*/
public void setSingle(ByteBuffer bytes) {
set(bytes);
}
/**
* Update the command output with a big number. Concrete {@link CommandOutput} implementations must override this method to
* decode {@code big number} response values.
*
* @param bytes The command output, or null.
* @since 6.0/RESP 3
*/
public void setBigNumber(ByteBuffer bytes) {
set(bytes);
}
/**
* Update the command output with a 64-bit signed integer. Concrete {@link CommandOutput} implementations must override this
* method to decode {@code number} (integer) response values.
*
* @param integer The command output.
*/
public void set(long integer) {
throw new UnsupportedOperationException(getClass().getName() + " does not support set(long)");
}
/**
* Update the command output with a floating-point number. Concrete {@link CommandOutput} implementations must override this
* method to decode {@code double} response values.
*
* @param number The command output.
* @since 6.0/RESP 3
*/
public void set(double number) {
throw new UnsupportedOperationException(getClass().getName() + " does not support set(double)");
}
/**
* Update the command output with a boolean. Concrete {@link CommandOutput} implementations must override this method to
* decode {@code boolean} response values.
*
* @param value The command output.
* @since 6.0/RESP 3
*/
public void set(boolean value) {
throw new UnsupportedOperationException(getClass().getName() + " does not support set(boolean)");
}
/**
* Set command output to an error message from the server.
*
* @param error Error message.
*/
public void setError(ByteBuffer error) {
this.error = decodeAscii(error);
}
/**
* Set command output to an error message from the client.
*
* @param error Error message.
*/
public void setError(String error) {
this.error = error;
}
/**
* Check if the command resulted in an error.
*
* @return true if command resulted in an error.
*/
public boolean hasError() {
return this.error != null;
}
/**
* Get the error that occurred.
*
* @return The error.
*/
public String getError() {
return error;
}
/**
* Mark the command output complete.
*
* @param depth Remaining depth of output queue.
*
*/
public void complete(int depth) {
// nothing to do by default
}
protected String decodeAscii(ByteBuffer bytes) {
if (bytes == null) {
return null;
}
char[] chars = new char[bytes.remaining()];
for (int i = 0; i < chars.length; i++) {
chars[i] = (char) bytes.get();
}
return new String(chars);
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
sb.append(getClass().getSimpleName());
sb.append(" [output=").append(output);
sb.append(", error='").append(error).append('\'');
sb.append(']');
return sb.toString();
}
/**
* Mark the beginning of a multi sequence (array).
*
* @param count expected number of elements in this multi sequence.
*/
public void multi(int count) {
}
/**
* Mark the beginning of a multi sequence (array).
*
* @param count expected number of elements in this multi sequence.
* @since 6.0/RESP 3
*/
public void multiArray(int count) {
multi(count);
}
/**
* Mark the beginning of a multi sequence (push-array).
*
* @param count expected number of elements in this multi sequence.
* @since 6.0/RESP 3
*/
public void multiPush(int count) {
multi(count);
}
/**
* Mark the beginning of a multi sequence (map).
*
* @param count expected number of elements in this multi sequence.
* @since 6.0/RESP 3
*/
public void multiMap(int count) {
multi(count * 2);
}
/**
* Mark the beginning of a set.
*
* @param count expected number of elements in this multi sequence.
* @since 6.0/RESP 3
*/
public void multiSet(int count) {
multi(count);
}
}