/*
* 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.table;
import org.h2.result.SortOrder;
import org.h2.util.HasSQL;
import org.h2.util.ParserUtil;
/**
* This represents a column item of an index. This is required because some
* indexes support descending sorted columns.
*/
public class IndexColumn {
/**
* Do not append ordering.
*/
public static final int SQL_NO_ORDER = 0x8000_0000;
/**
* The column name.
*/
public final String columnName;
/**
* The column, or null if not set.
*/
public Column column;
/**
* The sort type. Ascending (the default) and descending are supported;
* nulls can be sorted first or last.
*/
public int sortType = SortOrder.ASCENDING;
/**
* Appends the specified columns to the specified builder.
*
* @param builder
* string builder
* @param columns
* index columns
* @param sqlFlags
* formatting flags
* @return the specified string builder
*/
public static StringBuilder writeColumns(StringBuilder builder, IndexColumn[] columns, int sqlFlags) {
return writeColumns(builder, columns, 0, columns.length, sqlFlags);
}
/**
* Appends the specified columns to the specified builder.
*
* @param builder
* string builder
* @param startOffset
* start offset, inclusive
* @param endOffset
* end offset, exclusive
* @param columns
* index columns
* @param sqlFlags
* formatting flags
* @return the specified string builder
*/
public static StringBuilder writeColumns(StringBuilder builder, IndexColumn[] columns, int startOffset,
int endOffset, int sqlFlags) {
for (int i = startOffset; i < endOffset; i++) {
if (i > startOffset) {
builder.append(", ");
}
columns[i].getSQL(builder, sqlFlags);
}
return builder;
}
/**
* Appends the specified columns to the specified builder.
*
* @param builder
* string builder
* @param columns
* index columns
* @param separator
* separator
* @param suffix
* additional SQL to append after each column
* @param sqlFlags
* formatting flags
* @return the specified string builder
*/
public static StringBuilder writeColumns(StringBuilder builder, IndexColumn[] columns, String separator,
String suffix, int sqlFlags) {
for (int i = 0, l = columns.length; i < l; i++) {
if (i > 0) {
builder.append(separator);
}
columns[i].getSQL(builder, sqlFlags).append(suffix);
}
return builder;
}
/**
* Creates a new instance with the specified name.
*
* @param columnName
* the column name
*/
public IndexColumn(String columnName) {
this.columnName = columnName;
}
/**
* Creates a new instance with the specified name.
*
* @param columnName
* the column name
* @param sortType
* the sort type
*/
public IndexColumn(String columnName, int sortType) {
this.columnName = columnName;
this.sortType = sortType;
}
/**
* Creates a new instance with the specified column.
*
* @param column
* the column
*/
public IndexColumn(Column column) {
columnName = null;
this.column = column;
}
/**
* Appends the SQL snippet for this index column to the specified string builder.
*
* @param builder
* string builder
* @param sqlFlags
* formatting flags
* @return the specified string builder
*/
public StringBuilder getSQL(StringBuilder builder, int sqlFlags) {
if (column != null) {
column.getSQL(builder, sqlFlags);
} else {
ParserUtil.quoteIdentifier(builder, columnName, sqlFlags);
}
if ((sqlFlags & SQL_NO_ORDER) == 0) {
SortOrder.typeToString(builder, sortType);
}
return builder;
}
/**
* Create an array of index columns from a list of columns. The default sort
* type is used.
*
* @param columns the column list
* @return the index column array
*/
public static IndexColumn[] wrap(Column[] columns) {
IndexColumn[] list = new IndexColumn[columns.length];
for (int i = 0; i < list.length; i++) {
list[i] = new IndexColumn(columns[i]);
}
return list;
}
/**
* Map the columns using the column names and the specified table.
*
* @param indexColumns the column list with column names set
* @param table the table from where to map the column names to columns
*/
public static void mapColumns(IndexColumn[] indexColumns, Table table) {
for (IndexColumn col : indexColumns) {
col.column = table.getColumn(col.columnName);
}
}
@Override
public String toString() {
return getSQL(new StringBuilder("IndexColumn "), HasSQL.TRACE_SQL_FLAGS).toString();
}
}