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 and Description
static int	CLOSE_SQL_IDENTIFIER directive for ending an SQL identifier
static int	CLOSE_SQL_STRING_LITERAL directive for ending an SQL string literal
private static Character	DOUBLE_QUOTE
static int	INDENT directive for increasing the indentation level
static String	INDENT_SPACE4 four-space indentation
static String	INDENT_TAB tab indentation
private String	indentation
private int	indentationDepth
private boolean	needIndent
static int	OPEN_SQL_IDENTIFIER directive for beginning an SQL identifier
static int	OPEN_SQL_STRING_LITERAL directive for beginning an SQL string literal
static int	OUTDENT directive for decreasing the indentation level
private Deque<Character>	quoteStack
private static Character	SINGLE_QUOTE

Fields inherited from class java.io.FilterWriter

out

Fields inherited from class java.io.Writer

lock

Constructor Summary

Constructors

Constructor and 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 and Description
private void	indentIfNeeded()
private void	popQuote(Character quoteChar)
static void	printSqlIdentifier(PrintWriter pw, String s) Writes an SQL identifier.
static void	printSqlStringLiteral(PrintWriter pw, String s) Writes an SQL string literal.
private void	pushQuote(Character quoteChar)
void	write(char[] cbuf, int off, int len)
void	write(int c)
void	write(String str, int off, int len)
private void	writeQuote(Character quoteChar)

Methods inherited from class java.io.FilterWriter

close, flush

Methods inherited from class java.io.Writer

append, append, append, write, write

Methods inherited from class java.lang.Object

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

Field Detail

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

SINGLE_QUOTE

private static final Character SINGLE_QUOTE

DOUBLE_QUOTE

private static final Character DOUBLE_QUOTE

indentationDepth

private int indentationDepth

indentation

private String indentation

needIndent

private boolean needIndent

quoteStack

private final Deque<Character> quoteStack

Constructor Detail

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 Detail

indentIfNeeded

private void indentIfNeeded()
                     throws IOException

Throws:

IOException

writeQuote

private void writeQuote(Character quoteChar)
                 throws IOException

Throws:

IOException

pushQuote

private void pushQuote(Character quoteChar)
                throws IOException

Throws:

IOException

popQuote

private void popQuote(Character quoteChar)
               throws IOException

Throws:

IOException

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