Package org.apache.calcite.util

Class StackWriter

java.lang.Object

java.io.Writer

java.io.FilterWriter

org.apache.calcite.util.StackWriter

All Implemented Interfaces:

Closeable, Flushable, Appendable, AutoCloseable

public class StackWriter
extends FilterWriter

A helper class for generating formatted text. StackWriter keeps track of nested formatting state like indentation level and quote escaping. Typically, it is inserted between a PrintWriter and the real Writer; directives are passed straight through the PrintWriter via the write method, as in the following example:

    StringWriter sw = new StringWriter();
    StackWriter stackw = new StackWriter(sw, StackWriter.INDENT_SPACE4);
    PrintWriter pw = new PrintWriter(stackw);
    pw.write(StackWriter.INDENT);
    pw.print("execute remote(link_name,");
    pw.write(StackWriter.OPEN_SQL_STRING_LITERAL);
    pw.println();
    pw.write(StackWriter.INDENT);
    pw.println("select * from t where c > 'alabama'");
    pw.write(StackWriter.OUTDENT);
    pw.write(StackWriter.CLOSE_SQL_STRING_LITERAL);
    pw.println(");");
    pw.write(StackWriter.OUTDENT);
    pw.close();
    System.out.println(sw.toString());
 

which produces the following output:

      execute remote(link_name,'
          select * from t where c > ''alabama''
      ');
 

Field Summary

Fields

Modifier and Type	Field	Description
static final int	CLOSE_SQL_IDENTIFIER	Directive for ending an SQL identifier.
static final int	CLOSE_SQL_STRING_LITERAL	Directive for ending an SQL string literal.
static final int	INDENT	Directive for increasing the indentation level.
static final String	INDENT_SPACE4	Four-space indentation.
static final String	INDENT_TAB	Tab indentation.
static final int	OPEN_SQL_IDENTIFIER	Directive for beginning an SQL identifier.
static final int	OPEN_SQL_STRING_LITERAL	Directive for beginning an SQL string literal.
static final int	OUTDENT	Directive for decreasing the indentation level.

Fields inherited from class java.io.FilterWriter

out

Fields inherited from class java.io.Writer

lock

Constructor Summary

Constructors

Constructor	Description
StackWriter(Writer writer, String indentation)	Creates a new StackWriter on top of an existing Writer, with the specified string to be used for each level of indentation.

Method Summary

Modifier and Type	Method	Description
static void	printSqlIdentifier(PrintWriter pw, String s)	Writes an SQL identifier.
static void	printSqlStringLiteral(PrintWriter pw, String s)	Writes an SQL string literal.
void	write(char[] cbuf, int off, int len)
void	write(int c)
void	write(String str, int off, int len)

Methods inherited from class java.io.FilterWriter

close, flush

Methods inherited from class java.io.Writer

append, append, append, nullWriter, write, write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

INDENT

public static final int INDENT

Directive for increasing the indentation level.

See Also:

• Constant Field Values

OUTDENT

public static final int OUTDENT

Directive for decreasing the indentation level.

See Also:

• Constant Field Values

OPEN_SQL_STRING_LITERAL

public static final int OPEN_SQL_STRING_LITERAL

Directive for beginning an SQL string literal.

See Also:

• Constant Field Values

CLOSE_SQL_STRING_LITERAL

public static final int CLOSE_SQL_STRING_LITERAL

Directive for ending an SQL string literal.

See Also:

• Constant Field Values

OPEN_SQL_IDENTIFIER

public static final int OPEN_SQL_IDENTIFIER

Directive for beginning an SQL identifier.

See Also:

• Constant Field Values

CLOSE_SQL_IDENTIFIER

public static final int CLOSE_SQL_IDENTIFIER

Directive for ending an SQL identifier.

See Also:

• Constant Field Values

INDENT_TAB

public static final String INDENT_TAB

Tab indentation.

See Also:

• Constant Field Values

INDENT_SPACE4

public static final String INDENT_SPACE4

Four-space indentation.

See Also:

• Constant Field Values

Constructor Details

StackWriter

public StackWriter(Writer writer,
 String indentation)

Creates a new StackWriter on top of an existing Writer, with the specified string to be used for each level of indentation.

Parameters:

writer - underlying writer

indentation - indentation unit such as INDENT_TAB or INDENT_SPACE4

Method Details

write

public void write(int c)
           throws IOException

Overrides:

write in class FilterWriter

Throws:

IOException

write

public void write(char[] cbuf,
 int off,
 int len)
           throws IOException

Overrides:

write in class FilterWriter

Throws:

IOException

write

public void write(String str,
 int off,
 int len)
           throws IOException

Overrides:

write in class FilterWriter

Throws:

IOException

printSqlStringLiteral

public static void printSqlStringLiteral(PrintWriter pw,
 String s)

Writes an SQL string literal.

Parameters:

pw - PrintWriter on which to write

s - text of literal

printSqlIdentifier

public static void printSqlIdentifier(PrintWriter pw,
 String s)

Writes an SQL identifier.

Parameters:

pw - PrintWriter on which to write

s - identifier