PostgresqlRow.java

/*
 * Copyright 2017-2019 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;

import io.netty.buffer.ByteBuf;
import io.r2dbc.postgresql.codec.Codecs;
import io.r2dbc.postgresql.message.Format;
import io.r2dbc.postgresql.message.backend.DataRow;
import io.r2dbc.postgresql.message.backend.RowDescription;
import io.r2dbc.postgresql.util.Assert;
import io.r2dbc.spi.Row;
import reactor.util.annotation.Nullable;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * An implementation of {@link Row} for a PostgreSQL database.
 */
public final class PostgresqlRow implements Row {

    private final Codecs codecs;

    private final List<Column> columns;

    private final AtomicBoolean isReleased = new AtomicBoolean(false);

    private final Map<String, Column> nameKeyedColumns;

    PostgresqlRow(Codecs codecs, List<Column> columns) {
        this.codecs = Assert.requireNonNull(codecs, "codecs must not be null");
        this.columns = Assert.requireNonNull(columns, "columns must not be null");

        this.nameKeyedColumns = getNameKeyedColumns(this.columns);
    }

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

    @Nullable
    @Override
    public <T> T get(Object identifier, Class<T> type) {
        Assert.requireNonNull(identifier, "identifier must not be null");
        Assert.requireNonNull(type, "type must not be null");
        requireNotReleased();

        Column column;
        if (identifier instanceof Integer) {
            column = getColumn((Integer) identifier);
        } else if (identifier instanceof String) {
            column = getColumn((String) identifier);
        } else {
            throw new IllegalArgumentException(String.format("Identifier '%s' is not a valid identifier. Should either be an Integer index or a String column name.", identifier));
        }

        return this.codecs.decode(column.getByteBuf(), column.getDataType(), column.getFormat(), type);
    }

    @Override
    public int hashCode() {
        return Objects.hash(this.columns);
    }

    @Override
    public String toString() {
        return "PostgresqlRow{" +
            "codecs=" + this.codecs +
            ", columns=" + this.columns +
            ", isReleased=" + this.isReleased +
            ", nameKeyedColumns=" + this.nameKeyedColumns +
            '}';
    }

    static PostgresqlRow toRow(Codecs codecs, DataRow dataRow, RowDescription rowDescription) {
        Assert.requireNonNull(codecs, "codecs must not be null");
        Assert.requireNonNull(dataRow, "dataRow must not be null");
        Assert.requireNonNull(rowDescription, "rowDescription must not be null");

        List<Column> columns = getColumns(dataRow.getColumns(), rowDescription.getFields());
        dataRow.release();

        return new PostgresqlRow(codecs, columns);
    }

    void release() {
        this.columns.forEach(Column::release);
        this.isReleased.set(true);
    }

    private static List<Column> getColumns(List<ByteBuf> byteBufs, List<RowDescription.Field> fields) {
        List<Column> columns = new ArrayList<>(byteBufs.size());

        for (int i = 0; i < byteBufs.size(); i++) {
            ByteBuf byteBuf = byteBufs.get(i);
            RowDescription.Field field = fields.get(i);

            columns.add(new Column(byteBuf, field.getDataType(), field.getFormat(), field.getName()));
        }

        return columns;
    }

    private Column getColumn(String name) {
        if (!this.nameKeyedColumns.containsKey(name)) {
            throw new IllegalArgumentException(String.format("Column name '%s' does not exist in column names %s", name, this.nameKeyedColumns.keySet()));
        }

        return this.nameKeyedColumns.get(name);
    }

    private Column getColumn(Integer index) {
        if (index >= this.columns.size()) {
            throw new IllegalArgumentException(String.format("Column index %d is larger than the number of columns %d", index, this.columns.size()));
        }

        return this.columns.get(index);
    }

    private Map<String, Column> getNameKeyedColumns(List<Column> columns) {
        Map<String, Column> nameKeyedColumns = new HashMap<>(columns.size());

        for (Column column : columns) {
            nameKeyedColumns.put(column.getName(), column);
        }

        return nameKeyedColumns;
    }

    private void requireNotReleased() {
        if (this.isReleased.get()) {
            throw new IllegalStateException("Value cannot be retrieved after row has been released");
        }
    }

    static final class Column {

        private final ByteBuf byteBuf;

        private final Integer dataType;

        private final Format format;

        private final String name;

        Column(@Nullable ByteBuf byteBuf, Integer dataType, Format format, String name) {
            this.byteBuf = byteBuf == null ? null : byteBuf.retain();
            this.dataType = Assert.requireNonNull(dataType, "dataType must not be null");
            this.format = Assert.requireNonNull(format, "format must not be null");
            this.name = Assert.requireNonNull(name, "name must not be null");
        }

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

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

        @Override
        public String toString() {
            return "Column{" +
                "byteBuf=" + this.byteBuf +
                ", dataType=" + this.dataType +
                ", format=" + this.format +
                ", name='" + this.name + '\'' +
                '}';
        }

        private ByteBuf getByteBuf() {
            return this.byteBuf;
        }

        private Integer getDataType() {
            return this.dataType;
        }

        private Format getFormat() {
            return this.format;
        }

        private String getName() {
            return this.name;
        }

        private void release() {
            if (this.byteBuf != null) {
                this.byteBuf.release();
            }
        }

    }

}