org.drools.compiler.rule.builder.XpathAnalysis Maven / Gradle / Ivy
/*
* Copyright 2015 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
*
* 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.drools.compiler.rule.builder;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class XpathAnalysis implements Iterable {
private final List parts;
private final String error;
public XpathAnalysis( List parts, String error ) {
this.parts = parts;
this.error = error;
}
public boolean hasError() {
return error != null;
}
public String getError() {
return error;
}
@Override
public Iterator iterator() {
return parts.iterator();
}
public static class XpathPart {
private final String field;
private final boolean iterate;
private final boolean lazy;
private final List constraints;
private final String inlineCast;
private final int index;
public XpathPart(String field, boolean iterate, boolean lazy, List constraints, String inlineCast, int index) {
this.field = field;
this.iterate = iterate;
this.lazy = lazy;
this.constraints = constraints;
this.inlineCast = inlineCast;
this.index = index;
}
public String getField() {
return field;
}
public boolean isIterate() {
return iterate;
}
public boolean isLazy() {
return lazy;
}
public List getConstraints() {
return constraints;
}
public String getInlineCast() {
return inlineCast;
}
public int getIndex() {
return index;
}
public void addInlineCastConstraint(Class clazz) {
constraints.add(0, "this instanceof " + clazz.getCanonicalName());
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder( field );
if (index >= 0) {
sb.append( "[" ).append( index ).append( "]" );
}
if (!constraints.isEmpty()) {
sb.append( "{" );
sb.append( constraints.get(0) );
for (int i = 1; i < constraints.size(); i++) {
sb.append( ", " ).append( constraints.get( i ) );
}
sb.append( "}" );
}
return sb.toString();
}
}
public static XpathAnalysis analyze(String xpath) {
List parts = new ArrayList();
boolean lazyPath = false;
int i = 0;
if (xpath.charAt(0) == '/') {
i = 1;
} else if (xpath.charAt(0) == '?' && xpath.charAt(1) == '/') {
lazyPath = true;
i = 2;
} else {
new XpathAnalysis(parts, "An oopath expression has to start with '/' or '?/'");
}
List constraints = new ArrayList();
String inlineCast = null;
int index = -1;
int lastStart = i;
int nestedParam = 0;
int nestedCurly = 0;
int nestedSquare = 0;
boolean iterate = true;
boolean isQuoted = false;
String field = null;
String error = null;
for (; i < xpath.length() && error == null; i++) {
switch (xpath.charAt(i)) {
case '/':
case '.':
if (!isQuoted && nestedParam == 0 && nestedCurly == 0 && nestedSquare == 0) {
if (field == null) {
field = xpath.substring(lastStart, xpath.charAt(i-1) == '?' ? i-1 : i).trim();
}
parts.add(new XpathPart(field, iterate, lazyPath, constraints, inlineCast, index));
iterate = xpath.charAt(i) == '/';
if (xpath.charAt(i-1) == '?') {
if (lazyPath) {
error = "It is not possible to have 2 non-reactive parts in the same oopath";
break;
} else {
lazyPath = true;
}
}
constraints = new ArrayList();
inlineCast = null;
index = -1;
lastStart = i + 1;
field = null;
}
break;
case '(':
if (!isQuoted) {
nestedParam++;
}
break;
case ')':
if (!isQuoted) {
nestedParam--;
if (nestedParam < 0) {
error = "Unbalanced parenthesis";
}
}
break;
case '[':
if (!isQuoted && nestedParam == 0 && nestedCurly == 0) {
if (nestedSquare == 0) {
if (field == null) {
field = xpath.substring( lastStart, i ).trim();
}
lastStart = i+1;
}
nestedSquare++;
}
break;
case ']':
if (!isQuoted && nestedParam == 0 && nestedCurly == 0) {
nestedSquare--;
if (nestedSquare == 0) {
try {
index = Integer.parseInt( xpath.substring( lastStart, i ).trim() );
} catch (Exception e) {
error = "Expected int but found: " + xpath.substring( lastStart, i ).trim();
}
} else if (nestedSquare < 0) {
error = "Unbalanced square brackets";
}
}
break;
case '{':
if (!isQuoted && nestedParam == 0 && nestedSquare == 0) {
if (nestedCurly == 0) {
if (field == null) {
field = xpath.substring( lastStart, i ).trim();
}
lastStart = i+1;
}
nestedCurly++;
}
break;
case '}':
if (!isQuoted && nestedParam == 0 && nestedSquare == 0) {
nestedCurly--;
if (nestedCurly == 0) {
String constraint = xpath.substring(lastStart, i).trim();
if (constraint.startsWith("#")) {
inlineCast = constraint.substring(1);
} else {
constraints.add(constraint);
}
} else if (nestedCurly < 0) {
error = "Unbalanced curly braces";
}
}
break;
case ',':
if (!isQuoted && nestedParam == 0 && nestedCurly == 1) {
String constraint = xpath.substring(lastStart, i).trim();
if (constraint.startsWith("#")) {
inlineCast = constraint.substring(1);
} else {
constraints.add(constraint);
}
lastStart = i+1;
}
break;
case '"':
case '\'':
isQuoted = !isQuoted;
break;
}
}
if (field == null) {
field = xpath.substring(lastStart).trim();
}
parts.add(new XpathPart(field, iterate, lazyPath, constraints, inlineCast, index));
return new XpathAnalysis(parts, error);
}
}
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