/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.zookeeper.graph;
import java.io.PushbackReader;
import java.io.StringReader;
import java.io.IOException;
import java.util.ArrayList;
import org.apache.zookeeper.graph.filterops.*;
public class FilterParser {
private PushbackReader reader;
public FilterParser(String s) {
reader = new PushbackReader(new StringReader(s));
}
private String readUntilSpace() throws IOException {
StringBuffer buffer = new StringBuffer();
int c = reader.read();
while (!Character.isWhitespace(c) && c != ')' && c != '(') {
buffer.append((char)c);
c = reader.read();
if (c == -1) {
break;
}
}
reader.unread(c);
return buffer.toString().trim();
}
private StringArg readStringArg() throws IOException, FilterException {
int c = reader.read();
int last = 0;
if (c != '"') {
throw new FilterException("Check the parser, trying to read a string that doesn't begin with quotes");
}
StringBuffer buffer = new StringBuffer();
while (reader.ready()) {
last = c;
c = reader.read();
if (c == -1) {
break;
}
if (c == '"' && last != '\\') {
return new StringArg(buffer.toString());
} else {
buffer.append((char)c);
}
}
throw new FilterException("Unterminated string");
}
private NumberArg readNumberArg() throws IOException, FilterException {
String strval = readUntilSpace();
try {
if (strval.startsWith("0x")) {
return new NumberArg(Long.valueOf(strval.substring(2), 16));
} else {
return new NumberArg(Long.valueOf(strval));
}
} catch (NumberFormatException e) {
throw new FilterException("Not a number [" + strval + "]\n" + e);
}
}
private SymbolArg readSymbolArg() throws IOException, FilterException {
return new SymbolArg(readUntilSpace());
}
public FilterOp parse() throws IOException, FilterException {
int c = reader.read();
if (c != '(') {
throw new FilterException("Invalid format");
}
String opstr = readUntilSpace();
FilterOp op = FilterOp.newOp(opstr);
while (reader.ready()) {
c = reader.read();
if (c == -1) {
break;
}
if (c == '(') {
reader.unread(c);
op.addSubOp(parse());
} else if (c == ')') {
return op;
} else if (c == '"') {
reader.unread(c);
op.addArg(readStringArg());
} else if (Character.isDigit(c) || c == '-' || c == '+') {
reader.unread(c);
op.addArg(readNumberArg());
} else if (Character.isJavaIdentifierStart(c)) {
reader.unread(c);
op.addArg(readSymbolArg());
}
}
throw new FilterException("Incomplete filter");
}
public static void main(String[] args) throws IOException, FilterException {
if (args.length == 1) {
System.out.println(new FilterParser(args[0]).parse());
} else {
System.out.println(new FilterParser("(or (and (= session foobar) (= session barfoo)) (= session sdfs))").parse());
}
}
};