io.r2dbc.postgresql.message.frontend.Describe Maven / Gradle / Ivy

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Reactive Relational Database Connectivity Driver Implementation for Postgresql
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/*
 * Copyright 2017 the original author or authors.
 *
 * 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.r2dbc.postgresql.message.frontend;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.r2dbc.postgresql.util.Assert;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Mono;

import java.util.Objects;

import static io.r2dbc.postgresql.message.frontend.FrontendMessageUtils.writeByte;
import static io.r2dbc.postgresql.message.frontend.FrontendMessageUtils.writeCStringUTF8;
import static io.r2dbc.postgresql.message.frontend.FrontendMessageUtils.writeLengthPlaceholder;
import static io.r2dbc.postgresql.message.frontend.FrontendMessageUtils.writeSize;

/**
 * The Describe message.
 */
public final class Describe implements FrontendMessage, FrontendMessage.DirectEncoder {

    /**
     * The unnamed statement or portal.
     */
    public static final String UNNAMED = "";

    private final String name;

    private final ExecutionType type;

    /**
     * Create a new message.
     *
     * @param name The name of the prepared statement or portal to describe (an empty string selects the unnamed prepared statement or portal)
     * @param type the type to close
     * @throws IllegalArgumentException if {@code name} or {@code type} is {@code null}
     * @see #UNNAMED
     */
    public Describe(String name, ExecutionType type) {
        this.name = Assert.requireNonNull(name, "name must not be null");
        this.type = Assert.requireNonNull(type, "type must not be null");
    }

    @Override
    public Publisher encode(ByteBufAllocator byteBufAllocator) {
        Assert.requireNonNull(byteBufAllocator, "byteBufAllocator must not be null");

        return Mono.fromSupplier(() -> {
            ByteBuf out = byteBufAllocator.ioBuffer();

            encode(out);
            return out;
        });
    }

    @Override
    public void encode(ByteBuf byteBuf) {

        writeByte(byteBuf, 'D');

        int writerIndex = byteBuf.writerIndex();

        writeLengthPlaceholder(byteBuf);
        writeByte(byteBuf, this.type.getDiscriminator());
        writeCStringUTF8(byteBuf, this.name);
        writeSize(byteBuf, writerIndex);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        Describe that = (Describe) o;
        return Objects.equals(this.name, that.name) &&
            this.type == that.type;
    }

    @Override
    public int hashCode() {
        return Objects.hash(this.name, this.type);
    }

    @Override
    public String toString() {
        return "Describe{" +
            "name='" + this.name + '\'' +
            ", type=" + this.type +
            '}';
    }

}