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The ANTLR 4 grammar compiler.
/*
* [The "BSD license"]
* Copyright (c) 2012 Terence Parr
* Copyright (c) 2012 Sam Harwell
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.antlr.v4.codegen;
import org.antlr.v4.tool.ast.GrammarAST;
import org.stringtemplate.v4.STGroup;
import org.stringtemplate.v4.StringRenderer;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Locale;
import java.util.Set;
/**
*
* @author Sam Harwell
*/
public class JavaTarget extends Target {
/**
* The Java target can cache the code generation templates.
*/
private static final ThreadLocal targetTemplates = new ThreadLocal();
protected static final String[] javaKeywords = {
"abstract", "assert", "boolean", "break", "byte", "case", "catch",
"char", "class", "const", "continue", "default", "do", "double", "else",
"enum", "extends", "false", "final", "finally", "float", "for", "goto",
"if", "implements", "import", "instanceof", "int", "interface",
"long", "native", "new", "null", "package", "private", "protected",
"public", "return", "short", "static", "strictfp", "super", "switch",
"synchronized", "this", "throw", "throws", "transient", "true", "try",
"void", "volatile", "while"
};
/** Avoid grammar symbols in this set to prevent conflicts in gen'd code. */
protected final Set badWords = new HashSet();
public JavaTarget(CodeGenerator gen) {
super(gen, "Java");
}
public Set getBadWords() {
if (badWords.isEmpty()) {
addBadWords();
}
return badWords;
}
protected void addBadWords() {
badWords.addAll(Arrays.asList(javaKeywords));
badWords.add("rule");
badWords.add("parserRule");
}
/**
* {@inheritDoc}
*
* For Java, this is the translation {@code 'a\n"'} → {@code "a\n\""}.
* Expect single quotes around the incoming literal. Just flip the quotes
* and replace double quotes with {@code \"}.
*
*
* Note that we have decided to allow people to use '\"' without penalty, so
* we must build the target string in a loop as {@link String#replace}
* cannot handle both {@code \"} and {@code "} without a lot of messing
* around.
*
*/
@Override
public String getTargetStringLiteralFromANTLRStringLiteral(
CodeGenerator generator,
String literal, boolean addQuotes)
{
StringBuilder sb = new StringBuilder();
String is = literal;
if ( addQuotes ) sb.append('"');
for (int i = 1; i < is.length() -1; i++) {
if (is.charAt(i) == '\\') {
// Anything escaped is what it is! We assume that
// people know how to escape characters correctly. However
// we catch anything that does not need an escape in Java (which
// is what the default implementation is dealing with and remove
// the escape. The C target does this for instance.
//
switch (is.charAt(i+1)) {
// Pass through any escapes that Java also needs
//
case '"':
case 'n':
case 'r':
case 't':
case 'b':
case 'f':
case '\\':
// Pass the escape through
sb.append('\\');
break;
case 'u': // Assume unnnn
// Pass the escape through as double \\
// so that Java leaves as \u0000 string not char
sb.append('\\');
sb.append('\\');
break;
default:
// Remove the escape by virtue of not adding it here
// Thus \' becomes ' and so on
break;
}
// Go past the \ character
i++;
} else {
// Characters that don't need \ in ANTLR 'strings' but do in Java
if (is.charAt(i) == '"') {
// We need to escape " in Java
sb.append('\\');
}
}
// Add in the next character, which may have been escaped
sb.append(is.charAt(i));
}
if ( addQuotes ) sb.append('"');
return sb.toString();
}
@Override
public String encodeIntAsCharEscape(int v) {
if (v < Character.MIN_VALUE || v > Character.MAX_VALUE) {
throw new IllegalArgumentException(String.format("Cannot encode the specified value: %d", v));
}
if (v >= 0 && v < targetCharValueEscape.length && targetCharValueEscape[v] != null) {
return targetCharValueEscape[v];
}
if (v >= 0x20 && v < 127 && (!Character.isDigit(v) || v == '8' || v == '9')) {
return String.valueOf((char)v);
}
if ( v>=0 && v<=127 ) {
String oct = Integer.toOctalString(v);
return "\\"+ oct;
}
String hex = Integer.toHexString(v|0x10000).substring(1,5);
return "\\u"+hex;
}
@Override
public int getSerializedATNSegmentLimit() {
// 65535 is the class file format byte limit for a UTF-8 encoded string literal
// 3 is the maximum number of bytes it takes to encode a value in the range 0-0xFFFF
return 65535 / 3;
}
@Override
protected boolean visibleGrammarSymbolCausesIssueInGeneratedCode(GrammarAST idNode) {
return getBadWords().contains(idNode.getText());
}
@Override
protected STGroup loadTemplates() {
STGroup result = targetTemplates.get();
if (result == null) {
result = super.loadTemplates();
result.registerRenderer(String.class, new JavaStringRenderer(), true);
targetTemplates.set(result);
}
return result;
}
protected static class JavaStringRenderer extends StringRenderer {
@Override
public String toString(Object o, String formatString, Locale locale) {
if ("java-escape".equals(formatString)) {
// 5C is the hex code for the \ itself
return ((String)o).replace("\\u", "\\u005Cu");
}
return super.toString(o, formatString, locale);
}
}
}