package com.jayway.jsonpath.internal.filter;
import com.jayway.jsonpath.Filter;
import com.jayway.jsonpath.InvalidPathException;
import com.jayway.jsonpath.Predicate;
import com.jayway.jsonpath.internal.CharacterIndex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.List;
public class FilterCompiler {
private static final Logger logger = LoggerFactory.getLogger(FilterCompiler.class);
private static final char DOC_CONTEXT = '$';
private static final char EVAL_CONTEXT = '@';
private static final char OPEN_SQUARE_BRACKET = '[';
private static final char CLOSE_SQUARE_BRACKET = ']';
private static final char OPEN_PARENTHESIS = '(';
private static final char CLOSE_PARENTHESIS = ')';
private static final char OPEN_OBJECT = '{';
private static final char CLOSE_OBJECT = '}';
private static final char OPEN_ARRAY = '[';
private static final char CLOSE_ARRAY = ']';
private static final char SINGLE_QUOTE = '\'';
private static final char DOUBLE_QUOTE = '"';
private static final char SPACE = ' ';
private static final char PERIOD = '.';
private static final char AND = '&';
private static final char OR = '|';
private static final char MINUS = '-';
private static final char LT = '<';
private static final char GT = '>';
private static final char EQ = '=';
private static final char TILDE = '~';
private static final char TRUE = 't';
private static final char FALSE = 'f';
private static final char NULL = 'n';
private static final char NOT = '!';
private static final char PATTERN = '/';
private static final char IGNORE_CASE = 'i';
private CharacterIndex filter;
public static Filter compile(String filterString) {
FilterCompiler compiler = new FilterCompiler(filterString);
return new CompiledFilter(compiler.compile());
}
private FilterCompiler(String filterString) {
filter = new CharacterIndex(filterString);
filter.trim();
if (!filter.currentCharIs('[') || !filter.lastCharIs(']')) {
throw new InvalidPathException("Filter must start with '[' and end with ']'. " + filterString);
}
filter.incrementPosition(1);
filter.decrementEndPosition(1);
filter.trim();
if (!filter.currentCharIs('?')) {
throw new InvalidPathException("Filter must start with '[?' and end with ']'. " + filterString);
}
filter.incrementPosition(1);
filter.trim();
if (!filter.currentCharIs('(') || !filter.lastCharIs(')')) {
throw new InvalidPathException("Filter must start with '[?(' and end with ')]'. " + filterString);
}
}
public Predicate compile() {
try {
final ExpressionNode result = readLogicalOR();
filter.skipBlanks();
if (filter.inBounds()) {
throw new InvalidPathException(String.format("Expected end of filter expression instead of: %s",
filter.subSequence(filter.position(), filter.length())));
}
return result;
} catch (InvalidPathException e){
throw e;
} catch (Exception e) {
throw new InvalidPathException("Failed to parse filter: " + filter + ", error on position: " + filter.position() + ", char: " + filter.currentChar());
}
}
private ValueNode readValueNode() {
switch (filter.skipBlanks().currentChar()) {
case DOC_CONTEXT : return readPath();
case EVAL_CONTEXT : return readPath();
case NOT:
filter.incrementPosition(1);
switch (filter.skipBlanks().currentChar()) {
case DOC_CONTEXT : return readPath();
case EVAL_CONTEXT : return readPath();
default: throw new InvalidPathException(String.format("Unexpected character: %c", NOT));
}
default : return readLiteral();
}
}
private ValueNode readLiteral(){
switch (filter.skipBlanks().currentChar()){
case SINGLE_QUOTE: return readStringLiteral(SINGLE_QUOTE);
case DOUBLE_QUOTE: return readStringLiteral(DOUBLE_QUOTE);
case TRUE: return readBooleanLiteral();
case FALSE: return readBooleanLiteral();
case MINUS: return readNumberLiteral();
case NULL: return readNullLiteral();
case OPEN_OBJECT: return readJsonLiteral();
case OPEN_ARRAY: return readJsonLiteral();
case PATTERN: return readPattern();
default: return readNumberLiteral();
}
}
private ExpressionNode readLogicalOR() {
final List<ExpressionNode> ops = new ArrayList<ExpressionNode>();
ops.add(readLogicalAND());
while (true) {
int savepoint = filter.position();
try {
filter.readSignificantSubSequence(LogicalOperator.OR.getOperatorString());
ops.add(readLogicalAND());
}
catch (InvalidPathException exc) {
filter.setPosition(savepoint);
break;
}
}
return 1 == ops.size() ? ops.get(0) : LogicalExpressionNode.createLogicalOr(ops);
}
private ExpressionNode readLogicalAND() {
final List<ExpressionNode> ops = new ArrayList<ExpressionNode>();
ops.add(readLogicalANDOperand());
while (true) {
int savepoint = filter.position();
try {
filter.readSignificantSubSequence(LogicalOperator.AND.getOperatorString());
ops.add(readLogicalANDOperand());
}
catch (InvalidPathException exc) {
filter.setPosition(savepoint);
break;
}
}
return 1 == ops.size() ? ops.get(0) : LogicalExpressionNode.createLogicalAnd(ops);
}
private ExpressionNode readLogicalANDOperand() {
int savepoint = filter.skipBlanks().position();
if (filter.skipBlanks().currentCharIs(NOT)) {
filter.readSignificantChar(NOT);
switch (filter.skipBlanks().currentChar()) {
case DOC_CONTEXT:
case EVAL_CONTEXT:
filter.setPosition(savepoint);
break;
default:
final ExpressionNode op = readLogicalANDOperand();
return LogicalExpressionNode.createLogicalNot(op);
}
}
if (filter.skipBlanks().currentCharIs(OPEN_PARENTHESIS)) {
filter.readSignificantChar(OPEN_PARENTHESIS);
final ExpressionNode op = readLogicalOR();
filter.readSignificantChar(CLOSE_PARENTHESIS);
return op;
}
return readExpression();
}
private RelationalExpressionNode readExpression() {
ValueNode left = readValueNode();
int savepoint = filter.position();
try {
RelationalOperator operator = readRelationalOperator();
ValueNode right = readValueNode();
return new RelationalExpressionNode(left, operator, right);
}
catch (InvalidPathException exc) {
filter.setPosition(savepoint);
}
ValueNode.PathNode pathNode = left.asPathNode();
left = pathNode.asExistsCheck(pathNode.shouldExists());
RelationalOperator operator = RelationalOperator.EXISTS;
ValueNode right = left.asPathNode().shouldExists() ? ValueNode.TRUE : ValueNode.FALSE;
return new RelationalExpressionNode(left, operator, right);
}
private LogicalOperator readLogicalOperator(){
int begin = filter.skipBlanks().position();
int end = begin+1;
if(!filter.inBounds(end)){
throw new InvalidPathException("Expected boolean literal");
}
CharSequence logicalOperator = filter.subSequence(begin, end+1);
if(!logicalOperator.equals("||") && !logicalOperator.equals("&&")){
throw new InvalidPathException("Expected logical operator");
}
filter.incrementPosition(logicalOperator.length());
logger.trace("LogicalOperator from {} to {} -> [{}]", begin, end, logicalOperator);
return LogicalOperator.fromString(logicalOperator.toString());
}
private RelationalOperator readRelationalOperator() {
int begin = filter.skipBlanks().position();
if(isRelationalOperatorChar(filter.currentChar())){
while (filter.inBounds() && isRelationalOperatorChar(filter.currentChar())) {
filter.incrementPosition(1);
}
} else {
while (filter.inBounds() && filter.currentChar() != SPACE) {
filter.incrementPosition(1);
}
}
CharSequence operator = filter.subSequence(begin, filter.position());
logger.trace("Operator from {} to {} -> [{}]", begin, filter.position()-1, operator);
return RelationalOperator.fromString(operator.toString());
}
private ValueNode.NullNode readNullLiteral() {
int begin = filter.position();
if(filter.currentChar() == NULL && filter.inBounds(filter.position() + 3)){
CharSequence nullValue = filter.subSequence(filter.position(), filter.position() + 4);
if("null".equals(nullValue.toString())){
logger.trace("NullLiteral from {} to {} -> [{}]", begin, filter.position()+3, nullValue);
filter.incrementPosition(nullValue.length());
return ValueNode.createNullNode();
}
}
throw new InvalidPathException("Expected <null> value");
}
private ValueNode.JsonNode readJsonLiteral(){
int begin = filter.position();
char openChar = filter.currentChar();
assert openChar == OPEN_ARRAY || openChar == OPEN_OBJECT;
char closeChar = openChar == OPEN_ARRAY ? CLOSE_ARRAY : CLOSE_OBJECT;
int closingIndex = filter.indexOfMatchingCloseChar(filter.position(), openChar, closeChar, true, false);
if (closingIndex == -1) {
throw new InvalidPathException("String not closed. Expected " + SINGLE_QUOTE + " in " + filter);
} else {
filter.setPosition(closingIndex + 1);
}
CharSequence json = filter.subSequence(begin, filter.position());
logger.trace("JsonLiteral from {} to {} -> [{}]", begin, filter.position(), json);
return ValueNode.createJsonNode(json);
}
private ValueNode.PatternNode readPattern() {
int begin = filter.position();
int closingIndex = filter.nextIndexOfUnescaped(PATTERN);
if (closingIndex == -1) {
throw new InvalidPathException("Pattern not closed. Expected " + PATTERN + " in " + filter);
} else {
if(filter.inBounds(closingIndex+1) && filter.charAt(closingIndex+1) == IGNORE_CASE){
closingIndex++;
}
filter.setPosition(closingIndex + 1);
}
CharSequence pattern = filter.subSequence(begin, filter.position());
logger.trace("PatternNode from {} to {} -> [{}]", begin, filter.position(), pattern);
return ValueNode.createPatternNode(pattern);
}
private ValueNode.StringNode readStringLiteral(char endChar) {
int begin = filter.position();
int closingSingleQuoteIndex = filter.nextIndexOfUnescaped(endChar);
if (closingSingleQuoteIndex == -1) {
throw new InvalidPathException("String literal does not have matching quotes. Expected " + endChar + " in " + filter);
} else {
filter.setPosition(closingSingleQuoteIndex + 1);
}
CharSequence stringLiteral = filter.subSequence(begin, filter.position());
logger.trace("StringLiteral from {} to {} -> [{}]", begin, filter.position(), stringLiteral);
return ValueNode.createStringNode(stringLiteral, true);
}
private ValueNode.NumberNode readNumberLiteral() {
int begin = filter.position();
while (filter.inBounds() && filter.isNumberCharacter(filter.position())) {
filter.incrementPosition(1);
}
CharSequence numberLiteral = filter.subSequence(begin, filter.position());
logger.trace("NumberLiteral from {} to {} -> [{}]", begin, filter.position(), numberLiteral);
return ValueNode.createNumberNode(numberLiteral);
}
private ValueNode.BooleanNode readBooleanLiteral() {
int begin = filter.position();
int end = filter.currentChar() == TRUE ? filter.position() + 3 : filter.position() + 4;
if(!filter.inBounds(end)){
throw new InvalidPathException("Expected boolean literal");
}
CharSequence boolValue = filter.subSequence(begin, end+1);
if(!boolValue.equals("true") && !boolValue.equals("false")){
throw new InvalidPathException("Expected boolean literal");
}
filter.incrementPosition(boolValue.length());
logger.trace("BooleanLiteral from {} to {} -> [{}]", begin, end, boolValue);
return ValueNode.createBooleanNode(boolValue);
}
private ValueNode.PathNode readPath() {
char previousSignificantChar = filter.previousSignificantChar();
int begin = filter.position();
filter.incrementPosition(1);
while (filter.inBounds()) {
if (filter.currentChar() == OPEN_SQUARE_BRACKET) {
int closingSquareBracketIndex = filter.indexOfMatchingCloseChar(filter.position(), OPEN_SQUARE_BRACKET, CLOSE_SQUARE_BRACKET, true, false);
if (closingSquareBracketIndex == -1) {
throw new InvalidPathException("Square brackets does not match in filter " + filter);
} else {
filter.setPosition(closingSquareBracketIndex + 1);
}
}
boolean closingFunctionBracket = (filter.currentChar() == CLOSE_PARENTHESIS && currentCharIsClosingFunctionBracket(begin));
boolean closingLogicalBracket = (filter.currentChar() == CLOSE_PARENTHESIS && !closingFunctionBracket);
if (!filter.inBounds() || isRelationalOperatorChar(filter.currentChar()) || filter.currentChar() == SPACE || closingLogicalBracket) {
break;
} else {
filter.incrementPosition(1);
}
}
boolean shouldExists = !(previousSignificantChar == NOT);
CharSequence path = filter.subSequence(begin, filter.position());
return ValueNode.createPathNode(path, false, shouldExists);
}
private boolean expressionIsTerminated(){
char c = filter.currentChar();
if(c == CLOSE_PARENTHESIS || isLogicalOperatorChar(c)){
return true;
}
c = filter.nextSignificantChar();
if(c == CLOSE_PARENTHESIS || isLogicalOperatorChar(c)){
return true;
}
return false;
}
private boolean currentCharIsClosingFunctionBracket(int lowerBound){
if(filter.currentChar() != CLOSE_PARENTHESIS){
return false;
}
int idx = filter.indexOfPreviousSignificantChar();
if(idx == -1 || filter.charAt(idx) != OPEN_PARENTHESIS){
return false;
}
idx--;
while(filter.inBounds(idx) && idx > lowerBound){
if(filter.charAt(idx) == PERIOD){
return true;
}
idx--;
}
return false;
}
private boolean isLogicalOperatorChar(char c) {
return c == AND || c == OR;
}
private boolean isRelationalOperatorChar(char c) {
return c == LT || c == GT || c == EQ || c == TILDE || c == NOT;
}
private static final class CompiledFilter extends Filter {
private final Predicate predicate;
private CompiledFilter(Predicate predicate) {
this.predicate = predicate;
}
@Override
public boolean apply(Predicate.PredicateContext ctx) {
return predicate.apply(ctx);
}
@Override
public String toString() {
String predicateString = predicate.toString();
if(predicateString.startsWith("(")){
return "[?" + predicateString + "]";
} else {
return "[?(" + predicateString + ")]";
}
}
}
}
FilterCompiler
logger: Logger
