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A metacompilation framework for Java using attribute grammars.
/* Copyright (c) 2013, Jesper Öqvist
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jastadd.tinytemplate;
import java.io.InputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import org.jastadd.tinytemplate.Indentation.IndentationFragment;
import org.jastadd.tinytemplate.fragment.Fragment;
import org.jastadd.tinytemplate.fragment.NestedIndentationFragment;
/**
* Template
* @author Jesper Öqvist
*/
public class Template {
/**
* NB lines should never be empty!
*/
private final List> lines = new ArrayList>();
{
lines.add(new ArrayList());
}
/**
* Expand the template to a PrintStream
* @param context
* @param out
*/
public void expand(TemplateContext context, PrintStream out) {
StringBuilder buf = new StringBuilder();
for (List line: lines) {
expandLine(context, line, buf);
out.print(buf.toString());
}
}
/**
* Expand the template to a PrintWriter
* @param context
* @param out
*/
public void expand(TemplateContext context, PrintWriter out) {
StringBuilder buf = new StringBuilder();
for (List line: lines) {
expandLine(context, line, buf);
out.print(buf.toString());
}
}
/**
* Expand the template to a StringBuffer
* @param context
* @param out
*/
public void expand(TemplateContext context, StringBuffer out) {
StringBuilder buf = new StringBuilder();
for (List line: lines) {
expandLine(context, line, buf);
out.append(buf.toString());
}
}
/**
* Expand the template to a StringBuilder
* @param context
* @param out
*/
public void expand(TemplateContext context, StringBuilder out) {
StringBuilder buf = new StringBuilder();
for (List line: lines) {
expandLine(context, line, buf);
out.append(buf.toString());
}
}
/**
* Expand a single template line
* @param context
* @param line
* @param buf
*/
private void expandLine(TemplateContext context, List line,
StringBuilder buf) {
buf.setLength(0);
boolean expanded = false;
for (Fragment fragment : line) {
expanded |= fragment.isExpansion();
fragment.expand(context, buf);
}
// non-empty lines that become empty after expansion are deleted
if (expanded && isEmptyLine(buf)) {
buf.setLength(0);
}
}
private boolean isEmptyLine(StringBuilder buf) {
for (int i = 0; i < buf.length(); ++i) {
if (!Character.isWhitespace(buf.charAt(i)))
return false;
}
return true;
}
/**
* Load templates from file
* @param in
*/
public static void load(InputStream in) {
}
/**
* Add the indentation of the last line to a fragment
* @param fragment
*/
public void addIndentation(NestedIndentationFragment fragment) {
List lastLine = lines.get(lines.size()-1);
if (!lastLine.isEmpty() && lastLine.get(0).isIndentation()) {
fragment.setIndentation((IndentationFragment) lastLine.get(0));
}
}
/**
* Add a fragment to the last line
* @param fragment
*/
public void addFragment(Fragment fragment) {
lines.get(lines.size()-1).add(fragment);
if (fragment.isNewline()) {
lines.add(new ArrayList());
}
}
/**
* Trims first line from the template if it contains only whitespace.
* Trims leading and trailing whitespace surrounding conditionals that
* are alone on their line.
*/
public void trim() {
trimLeadingEmptyLine();
trimConditionalWhitespace();
}
/**
* Trim the first line from the template if it contains only whitespace
*/
private void trimLeadingEmptyLine() {
trimLineIfEmpty(0);
}
/**
* Trim the last line from the template if it contains only whitespace
*/
public void trimTrailingEmptyLine() {
trimLineIfEmpty(lines.size()-1);
}
/**
* Remove the given line if it contains only whitespace
* @param line Index of line to trim
*/
private void trimLineIfEmpty(int line) {
for (Fragment fragment: lines.get(line)) {
if (!fragment.isWhitespace()) {
return;
}
}
lines.remove(line);
if (line > 0) {
// remove newline from previous line
List prevLine = lines.get(line-1);
int last = prevLine.size()-1;
if (last >= 0 && prevLine.get(last).isNewline()) {
prevLine.remove(last);
if (last == 0) {
lines.remove(line-1);
}
}
}
if (lines.isEmpty()) {
// lines must not be empty
lines.add(new ArrayList());
}
}
/**
* Trim leading and trailing whitespace around conditionals surrounded
* by whitespace on their line.
*/
private void trimConditionalWhitespace() {
for (int i = 0; i < lines.size(); ++i) {
boolean trimmable = true;
boolean hasCond = false;
for (Fragment fragment: lines.get(i)) {
if ((!fragment.isWhitespace() && !fragment.isConditional())
|| fragment.isConditional() && hasCond) {
trimmable = false;
break;
}
hasCond |= fragment.isConditional();
}
List line = trimLine(lines.get(i), trimmable && hasCond);
lines.set(i, line);
}
}
private List trimLine(List line, boolean trimmable) {
List tmp = new ArrayList(lines.size());
for (Fragment frag: line) {
if (!trimmable || !frag.isWhitespace() || frag.isNewline()) {
tmp.add(frag);
}
}
return tmp;
}
/**
* Print inter-type declaration for this template
* @param ind Indentation handler
* @param lvl Indentation level
* @param out Output stream
*/
public void printITD(Indentation ind, int lvl, PrintStream out) {
for (List line: lines) {
for (Fragment fragment: line) {
fragment.printAspectCode(ind, lvl, out);
}
}
}
/**
* @return true if the template expands to an empty string
*/
public boolean isEmpty() {
return lines.size() == 1 && lines.get(0).size() == 0;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
expand(new DumbContext(), sb);
return sb.toString();
}
}