/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.result;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.Comparator;
import org.h2.engine.Session;
import org.h2.util.Utils;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
/**
* Simple in-memory result.
*/
public class SimpleResult implements ResultInterface, ResultTarget {
/**
* Column info for the simple result.
*/
static final class Column {
/** Column alias. */
final String alias;
/** Column name. */
final String columnName;
/** Column type. */
final TypeInfo columnType;
Column(String alias, String columnName, TypeInfo columnType) {
if (alias == null || columnName == null) {
throw new NullPointerException();
}
this.alias = alias;
this.columnName = columnName;
this.columnType = columnType;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + alias.hashCode();
result = prime * result + columnName.hashCode();
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null || getClass() != obj.getClass())
return false;
Column other = (Column) obj;
return alias.equals(other.alias) && columnName.equals(other.columnName);
}
@Override
public String toString() {
if (alias.equals(columnName)) {
return columnName;
}
return columnName + ' ' + alias;
}
}
private final ArrayList<Column> columns;
private final ArrayList<Value[]> rows;
private final String schemaName, tableName;
private int rowId;
/**
* Creates new instance of simple result.
*/
public SimpleResult() {
this("", "");
}
/**
* Creates new instance of simple result.
*
* @param schemaName
* the name of the schema
* @param tableName
* the name of the table
*/
public SimpleResult(String schemaName, String tableName) {
this.columns = Utils.newSmallArrayList();
this.rows = new ArrayList<>();
this.schemaName = schemaName;
this.tableName = tableName;
this.rowId = -1;
}
private SimpleResult(ArrayList<Column> columns, ArrayList<Value[]> rows, String schemaName, String tableName) {
this.columns = columns;
this.rows = rows;
this.schemaName = schemaName;
this.tableName = tableName;
this.rowId = -1;
}
/**
* Add column to the result.
*
* @param alias
* Column's alias.
* @param columnName
* Column's name.
* @param columnType
* Column's value type.
* @param columnPrecision
* Column's precision.
* @param columnScale
* Column's scale.
*/
public void addColumn(String alias, String columnName, int columnType, long columnPrecision, int columnScale) {
addColumn(alias, columnName, TypeInfo.getTypeInfo(columnType, columnPrecision, columnScale, null));
}
/**
* Add column to the result.
*
* @param columnName
* Column's name.
* @param columnType
* Column's type.
*/
public void addColumn(String columnName, TypeInfo columnType) {
addColumn(new Column(columnName, columnName, columnType));
}
/**
* Add column to the result.
*
* @param alias
* Column's alias.
* @param columnName
* Column's name.
* @param columnType
* Column's type.
*/
public void addColumn(String alias, String columnName, TypeInfo columnType) {
addColumn(new Column(alias, columnName, columnType));
}
/**
* Add column to the result.
*
* @param column
* Column info.
*/
void addColumn(Column column) {
assert rows.isEmpty();
columns.add(column);
}
@Override
public void addRow(Value... values) {
assert values.length == columns.size();
rows.add(values);
}
@Override
public void reset() {
rowId = -1;
}
@Override
public Value[] currentRow() {
return rows.get(rowId);
}
@Override
public boolean next() {
int count = rows.size();
if (rowId < count) {
return ++rowId < count;
}
return false;
}
@Override
public long getRowId() {
return rowId;
}
@Override
public boolean isAfterLast() {
return rowId >= rows.size();
}
@Override
public int getVisibleColumnCount() {
return columns.size();
}
@Override
public long getRowCount() {
return rows.size();
}
@Override
public boolean hasNext() {
return rowId < rows.size() - 1;
}
@Override
public boolean needToClose() {
return false;
}
@Override
public void close() {
// Do nothing for now
}
@Override
public String getAlias(int i) {
return columns.get(i).alias;
}
@Override
public String getSchemaName(int i) {
return schemaName;
}
@Override
public String getTableName(int i) {
return tableName;
}
@Override
public String getColumnName(int i) {
return columns.get(i).columnName;
}
@Override
public TypeInfo getColumnType(int i) {
return columns.get(i).columnType;
}
@Override
public boolean isIdentity(int i) {
return false;
}
@Override
public int getNullable(int i) {
return ResultSetMetaData.columnNullableUnknown;
}
@Override
public void setFetchSize(int fetchSize) {
// Ignored
}
@Override
public int getFetchSize() {
return 1;
}
@Override
public boolean isLazy() {
return false;
}
@Override
public boolean isClosed() {
return false;
}
@Override
public SimpleResult createShallowCopy(Session targetSession) {
return new SimpleResult(columns, rows, schemaName, tableName);
}
@Override
public void limitsWereApplied() {
// Nothing to do
}
/**
* Sort rows in the list.
*
* @param comparator
* the comparator
*/
public void sortRows(Comparator<? super Value[]> comparator) {
rows.sort(comparator);
}
}