/**
* 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.cxf.jaxrs.ext.search.fiql;
import java.text.DateFormat;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.xml.datatype.DatatypeConfigurationException;
import javax.xml.datatype.DatatypeFactory;
import org.apache.cxf.jaxrs.ext.search.AndSearchCondition;
import org.apache.cxf.jaxrs.ext.search.Beanspector;
import org.apache.cxf.jaxrs.ext.search.ConditionType;
import org.apache.cxf.jaxrs.ext.search.OrSearchCondition;
import org.apache.cxf.jaxrs.ext.search.SearchBean;
import org.apache.cxf.jaxrs.ext.search.SearchCondition;
import org.apache.cxf.jaxrs.ext.search.SearchConditionParser;
import org.apache.cxf.jaxrs.ext.search.SearchParseException;
import org.apache.cxf.jaxrs.ext.search.SearchUtils;
import org.apache.cxf.jaxrs.ext.search.SimpleSearchCondition;
import org.apache.cxf.jaxrs.utils.InjectionUtils;
/**
* Parses <a href="http://tools.ietf.org/html/draft-nottingham-atompub-fiql-00">FIQL</a> expression to
* construct {@link SearchCondition} structure. Since this class operates on Java type T, not on XML
* structures "selectors" part of specification is not applicable; instead selectors describes getters of type
* T used as search condition type (see {@link SimpleSearchCondition#isMet(Object)} for details.
*
* @param <T> type of search condition.
*/
public class FiqlParser<T> implements SearchConditionParser<T> {
public static final String OR = ",";
public static final String AND = ";";
public static final String GT = "=gt=";
public static final String GE = "=ge=";
public static final String LT = "=lt=";
public static final String LE = "=le=";
public static final String EQ = "==";
public static final String NEQ = "!=";
public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSZ";
private static final Pattern COMPARATORS_PATTERN;
private static final Map<String, ConditionType> OPERATORS_MAP;
static {
// operatorsMap
OPERATORS_MAP = new HashMap<String, ConditionType>();
OPERATORS_MAP.put(GT, ConditionType.GREATER_THAN);
OPERATORS_MAP.put(GE, ConditionType.GREATER_OR_EQUALS);
OPERATORS_MAP.put(LT, ConditionType.LESS_THAN);
OPERATORS_MAP.put(LE, ConditionType.LESS_OR_EQUALS);
OPERATORS_MAP.put(EQ, ConditionType.EQUALS);
OPERATORS_MAP.put(NEQ, ConditionType.NOT_EQUALS);
// pattern
String comparators = GT + "|" + GE + "|" + LT + "|" + LE + "|" + EQ + "|" + NEQ;
String s1 = "[\\p{ASCII}]+(" + comparators + ")";
COMPARATORS_PATTERN = Pattern.compile(s1);
}
private Beanspector<T> beanspector;
private Class<T> conditionClass;
private Map<String, String> properties;
/**
* Creates FIQL parser.
*
* @param tclass - class of T used to create condition objects in built syntax tree. Class T must have
* accessible no-arg constructor and complementary setters to these used in FIQL expressions.
*/
public FiqlParser(Class<T> tclass) {
this(tclass, Collections.<String, String>emptyMap());
}
/**
* Creates FIQL parser.
*
* @param tclass - class of T used to create condition objects in built syntax tree. Class T must have
* accessible no-arg constructor and complementary setters to these used in FIQL expressions.
* @param contextProperties
*/
public FiqlParser(Class<T> tclass, Map<String, String> contextProperties) {
beanspector = SearchBean.class.isAssignableFrom(tclass)
? null : new Beanspector<T>(tclass);
conditionClass = tclass;
properties = contextProperties;
}
/**
* Parses expression and builds search filter. Names used in FIQL expression are names of getters/setters
* in type T.
* <p>
* Example:
*
* <pre>
* class Condition {
* public String getFoo() {...}
* public void setFoo(String foo) {...}
* public int getBar() {...}
* public void setBar(int bar) {...}
* }
*
* FiqlParser<Condition> parser = new FiqlParser<Condition>(Condition.class);
* parser.parse("foo==mystery*;bar=ge=10");
* </pre>
*
* @param fiqlExpression expression of filter.
* @return tree of {@link SearchCondition} objects representing runtime search structure.
* @throws SearchParseException when expression does not follow FIQL grammar
*/
public SearchCondition<T> parse(String fiqlExpression) throws SearchParseException {
ASTNode<T> ast = parseAndsOrsBrackets(fiqlExpression);
// System.out.println(ast);
return ast.build();
}
private ASTNode<T> parseAndsOrsBrackets(String expr) throws SearchParseException {
List<String> subexpressions = new ArrayList<String>();
List<String> operators = new ArrayList<String>();
int level = 0;
int lastIdx = 0;
int idx = 0;
for (idx = 0; idx < expr.length(); idx++) {
char c = expr.charAt(idx);
if (c == '(') {
level++;
} else if (c == ')') {
level--;
if (level < 0) {
throw new SearchParseException(String.format("Unexpected closing bracket at position %d",
idx));
}
}
String cs = Character.toString(c);
boolean isOperator = AND.equals(cs) || OR.equals(cs);
if (level == 0 && isOperator) {
String s1 = expr.substring(lastIdx, idx);
String s2 = expr.substring(idx, idx + 1);
subexpressions.add(s1);
operators.add(s2);
lastIdx = idx + 1;
}
boolean isEnd = idx == expr.length() - 1;
if (isEnd) {
String s1 = expr.substring(lastIdx, idx + 1);
subexpressions.add(s1);
operators.add(null);
lastIdx = idx + 1;
}
}
if (level != 0) {
throw new SearchParseException(String
.format("Unmatched opening and closing brackets in expression: %s", expr));
}
if (operators.get(operators.size() - 1) != null) {
String op = operators.get(operators.size() - 1);
String ex = subexpressions.get(subexpressions.size() - 1);
throw new SearchParseException("Dangling operator at the end of expression: ..." + ex + op);
}
// looking for adjacent ANDs then group them into ORs
// Note: in case not ANDs is found (e.g only ORs) every single subexpression is
// treated as "single item group of ANDs"
int from = 0;
int to = 0;
SubExpression ors = new SubExpression(OR);
while (to < operators.size()) {
while (to < operators.size() && AND.equals(operators.get(to))) {
to++;
}
SubExpression ands = new SubExpression(AND);
for (; from <= to; from++) {
String subex = subexpressions.get(from);
ASTNode<T> node = null;
if (subex.startsWith("(")) {
node = parseAndsOrsBrackets(subex.substring(1, subex.length() - 1));
} else {
node = parseComparison(subex);
}
ands.add(node);
}
to = from;
if (ands.getSubnodes().size() == 1) {
ors.add(ands.getSubnodes().get(0));
} else {
ors.add(ands);
}
}
if (ors.getSubnodes().size() == 1) {
return ors.getSubnodes().get(0);
} else {
return ors;
}
}
private Comparison parseComparison(String expr) throws SearchParseException {
Matcher m = COMPARATORS_PATTERN.matcher(expr);
if (m.find()) {
String name = expr.substring(0, m.start(1));
String operator = m.group(1);
String value = expr.substring(m.end(1));
if ("".equals(value)) {
throw new SearchParseException("Not a comparison expression: " + expr);
}
Object castedValue = parseDatatype(name, value);
return new Comparison(name, operator, castedValue);
} else {
throw new SearchParseException("Not a comparison expression: " + expr);
}
}
private Object parseDatatype(String setter, String value) throws SearchParseException {
Object castedValue = value;
Class<?> valueType;
try {
valueType = beanspector != null ? beanspector.getAccessorType(setter) : String.class;
} catch (Exception e) {
throw new SearchParseException(e);
}
if (Date.class.isAssignableFrom(valueType)) {
try {
DateFormat df = SearchUtils.getDateFormat(properties, DEFAULT_DATE_FORMAT);
String dateValue = value;
if (SearchUtils.isTimeZoneSupported(properties, Boolean.TRUE)) {
// zone in XML is "+01:00" in Java is "+0100"; stripping semicolon
int idx = value.lastIndexOf(':');
if (idx != -1) {
dateValue = value.substring(0, idx) + value.substring(idx + 1);
}
}
castedValue = df.parse(dateValue);
} catch (ParseException e) {
// is that duration?
try {
Date now = new Date();
DatatypeFactory.newInstance().newDuration(value).addTo(now);
castedValue = now;
} catch (DatatypeConfigurationException e1) {
throw new SearchParseException(e1);
} catch (IllegalArgumentException e1) {
throw new SearchParseException("Can parse " + value + " neither as date nor duration", e);
}
}
} else {
try {
castedValue = InjectionUtils.convertStringToPrimitive(value, valueType);
} catch (Exception e) {
throw new SearchParseException("Cannot convert String value \"" + value
+ "\" to a value of class " + valueType.getName(), e);
}
}
return castedValue;
}
// node of abstract syntax tree
private interface ASTNode<T> {
SearchCondition<T> build() throws SearchParseException;
}
private class SubExpression implements ASTNode<T> {
private String operator;
private List<ASTNode<T>> subnodes = new ArrayList<ASTNode<T>>();
public SubExpression(String operator) {
this.operator = operator;
}
public void add(ASTNode<T> node) {
subnodes.add(node);
}
public List<ASTNode<T>> getSubnodes() {
return Collections.unmodifiableList(subnodes);
}
@Override
public String toString() {
String s = operator.equals(AND) ? "AND" : "OR";
s += ":[";
for (int i = 0; i < subnodes.size(); i++) {
s += subnodes.get(i);
if (i < subnodes.size() - 1) {
s += ", ";
}
}
s += "]";
return s;
}
public SearchCondition<T> build() throws SearchParseException {
boolean hasSubtree = false;
for (ASTNode<T> node : subnodes) {
if (node instanceof FiqlParser.SubExpression) {
hasSubtree = true;
break;
}
}
if (!hasSubtree && AND.equals(operator) && beanspector != null) {
try {
// Optimization: single SimpleSearchCondition for 'AND' conditions
Map<String, ConditionType> map = new LinkedHashMap<String, ConditionType>();
beanspector.instantiate();
for (ASTNode<T> node : subnodes) {
FiqlParser<T>.Comparison comp = (Comparison)node;
map.put(comp.getName(), OPERATORS_MAP.get(comp.getOperator()));
beanspector.setValue(comp.getName(), comp.getValue());
}
return new SimpleSearchCondition<T>(map, beanspector.getBean());
} catch (Throwable e) {
throw new RuntimeException(e);
}
} else {
List<SearchCondition<T>> scNodes = new ArrayList<SearchCondition<T>>();
for (ASTNode<T> node : subnodes) {
scNodes.add(node.build());
}
if (OR.equals(operator)) {
return new OrSearchCondition<T>(scNodes);
} else {
return new AndSearchCondition<T>(scNodes);
}
}
}
}
private class Comparison implements ASTNode<T> {
private String name;
private String operator;
private Object value;
public Comparison(String name, String operator, Object value) {
this.name = name;
this.operator = operator;
this.value = value;
}
public String getName() {
return name;
}
public String getOperator() {
return operator;
}
public Object getValue() {
return value;
}
@Override
public String toString() {
return name + " " + operator + " " + value + " (" + value.getClass().getSimpleName() + ")";
}
public SearchCondition<T> build() throws SearchParseException {
T cond = createTemplate(name, value);
ConditionType ct = OPERATORS_MAP.get(operator);
if (isPrimitive(cond)) {
return new SimpleSearchCondition<T>(ct, cond);
} else {
return new SimpleSearchCondition<T>(Collections.singletonMap(name, ct),
cond);
}
}
private boolean isPrimitive(T pojo) {
return pojo.getClass().getName().startsWith("java.lang");
}
@SuppressWarnings("unchecked")
private T createTemplate(String setter, Object val) throws SearchParseException {
try {
if (beanspector != null) {
beanspector.instantiate().setValue(setter, val);
return beanspector.getBean();
} else {
SearchBean bean = (SearchBean)conditionClass.newInstance();
bean.set(setter, value.toString());
return (T)bean;
}
} catch (Throwable e) {
throw new SearchParseException(e);
}
}
}
}