IndentingWriter.java
/*
** Module : IndentingWriter.java
** Abstract : allows caller-controlled indenting of output
**
** Copyright (c) 2008-2017, Golden Code Development Corporation.
**
** -#- -I- --Date-- -T- --JPRM-- ----------------Description-----------------
** 001 GES 20080309 NEW @37540 Created initial version which allows
** caller-controlled indenting of output.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
** This license does not grant any license or rights to use the trademarks
** Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
** of Golden Code Development Corporation. You are not authorized to use the
** name Golden Code, FWD, or the names of any author or contributor, for
** publicity purposes without written authorization.
**
** 2. No Misrepresentation of Affiliation.
**
** You may not represent yourself as Golden Code Development Corporation or FWD.
**
** You may not represent yourself for publicity purposes as associated with
** Golden Code Development Corporation, FWD, or any author or contributor to
** the covered work, without written authorization.
**
** 3. No Misrepresentation of Source or Origin.
**
** You may not represent the covered work as solely your work. All modified
** versions of the covered work must be marked in a reasonable way to make it
** clear that the modified work is not originating from Golden Code Development
** Corporation or FWD. All modified versions must contain the notices of
** attribution required in this license.
*/
package com.goldencode.p2j.io;
import java.io.*;
/**
* Provides <code>Writer</code> semantics with caller-controlled
* indenting. An indent is written (inserted) between each newline and any
* subsequent (non-newline) characters that are written.
* <p>
* This class is not thread-safe.
*
* @author GES
*/
public class IndentingWriter
extends FilterWriter
implements Indentable
{
/** Indent state manager. */
private Indentable indent = new IndentHandler();
/** The last byte written to the stream. */
private char last = '\n';
/**
* Creates an instance with the associated writer as the base and
* a default 0 indent level.
*
* @param out
* The writer on which we filter.
*/
public IndentingWriter(Writer out)
{
super(out);
}
/**
* Creates an instance with the associated writer as the base.
*
* @param out
* The writer on which we filter.
* @param indent
* The initial indent level.
*/
public IndentingWriter(Writer out, int indent)
{
this(out);
this.indent.setIndent(indent);
}
/**
* Accesses the current indent level.
*
* @return Indent level.
*/
public int getIndent()
{
return indent.getIndent();
}
/**
* Sets the current indent level.
*
* @param indent
* New indent level.
*/
public void setIndent(int indent)
{
this.indent.setIndent(indent);
}
/**
* Increments the indent level by 1.
*/
public void increment()
{
indent.increment();
}
/**
* Decrements the indent level by 1.
*/
public void decrement()
{
indent.decrement();
}
/**
* Accesses the number of spaces in a single indent level.
*
* @return Width of each indent level.
*/
public int getWidth()
{
return indent.getWidth();
}
/**
* Sets the number of spaces in a single indent level.
*
* @param width
* New indent width.
*/
public void setWidth(int width)
{
indent.setWidth(width);
}
/**
* Sets both the indent level and the number of spaces in a single indent
* level. This is a convenience function to avoid 2 separate calls and
* the small amount of shared overhead that would have been incurred in
* those calls.
*
* @param indent
* New indent level.
* @param width
* New indent width.
*/
public void setPad(int indent, int width)
{
this.indent.setPad(indent, width);
}
/**
* Get the current pad.
*
* @return The pad string for the next line of output.
*/
public String getPad()
{
return indent.getPad();
}
/**
* Writes the specified character to this writer (only the low order 16
* bits are written, the high order 16 bits are ignored).
* <p>
* The current pad is inserted into the stream between all newline
* characters and any subsequent non-newline characters.
*
* @param ch
* The character to write.
*
* @throws IOException
* if an I/O error occurs. In particular, an IOException may be
* thrown if the writer has been closed.
*/
public void write(int ch)
throws IOException
{
write(new char[] { (char) ch });
}
/**
* Writes <code>len</code> characters from the specified string starting
* at offset <code>off</code> in this writer. Element <code>off</code> is
* the first character written and <code>off+len-1</code> is the last
* character written.
* <p>
* The current pad is inserted into the stream between all newline
* characters and any subsequent non-newline characters.
*
* @param str
* The string to write.
* @param off
* The start offset in the string.
* @param len
* The number of characters to write.
*
* @throws IOException
* If an I/O error occurs. In particular, an IOException may be
* thrown if the writer has been closed.
*
* @throws NullPointerException
* If the string is <code>null</code>.
* @throws IndexOutOfBoundsException
* If the offset or length are negative, or if offset + length
* is larger than the length of the string.
*/
public void write(String str, int off, int len)
throws IOException,
NullPointerException,
IndexOutOfBoundsException
{
write(str.toCharArray(), off, len);
}
/**
* Writes <code>len</code> characters from the specified character array
* starting at offset <code>off</code> in this writer. Element ch[off] is
* the first character written and ch[off+len-1] is the last character
* written.
* <p>
* The current pad is inserted into the stream between all newline
* characters and any subsequent non-newline characters.
*
* @param ch
* The array of characters to write.
* @param off
* The start offset in the array.
* @param len
* The number of characters to write.
*
* @throws IOException
* If an I/O error occurs. In particular, an IOException may be
* thrown if the writer has been closed.
*
* @throws NullPointerException
* If the array is <code>null</code>.
* @throws IndexOutOfBoundsException
* If the offset or length are negative, or if offset + length
* is larger than the length of the array.
*/
public void write(char[] ch, int off, int len)
throws IOException,
NullPointerException,
IndexOutOfBoundsException
{
boolean empty = (indent.getIndent() == 0 && indent.getWidth() == 0);
if (empty)
{
// no identing needed, use faster approach
out.write(ch, off, len);
// remember the last char
last = ch[off + len - 1];
}
else
{
// indent needed, process one byte at a time
for (int i = 0; i < len; i++)
{
char next = ch[i + off];
// look for an output of a non-newline that follows a newline
if (last == '\n' && next != '\n')
{
// insert the indent
out.write(indent.getPad().toCharArray());
}
// write the current character
out.write(next);
// update the last character
last = next;
}
}
}
}