/*
* Copyright 1999-2015 dangdang.com.
* <p>
* Licensed 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.
* </p>
*/
package com.dangdang.ddframe.rdb.sharding.config.common.internal.parser;
import com.google.common.base.Function;
import com.google.common.base.Splitter;
import com.google.common.collect.Collections2;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import groovy.lang.GString;
import groovy.lang.GroovyShell;
import lombok.RequiredArgsConstructor;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;
/**
* 行内配置解析器.
*
* @author gaohongtao
* @author zhangliang
*/
@RequiredArgsConstructor
public final class InlineParser {
private static final char SPLITTER = ',';
private final String inlineExpression;
/**
* 分隔行内配置.
*
* @return 分隔后的配置集合
*/
public List<String> split() {
return Splitter.on(SPLITTER).trimResults().splitToList(inlineExpression);
}
/**
* 分隔并求inline表达式值.
*
* @return 求值后的配置集合
*/
public List<String> evaluate() {
final GroovyShell shell = new GroovyShell();
return flattenSegments(Lists.transform(splitWithInlineExpression(), new Function<String, Object>() {
@Override
public Object apply(final String input) {
StringBuilder expression = new StringBuilder(input);
if (!input.startsWith("\"")) {
expression.insert(0, "\"");
}
if (!input.endsWith("\"")) {
expression.append("\"");
}
return shell.evaluate(expression.toString());
}
}));
}
List<String> splitWithInlineExpression() {
List<String> result = new ArrayList<>();
StringBuilder segment = new StringBuilder();
int bracketsDepth = 0;
for (int i = 0; i < inlineExpression.length(); i++) {
char each = inlineExpression.charAt(i);
switch (each) {
case SPLITTER:
if (bracketsDepth > 0) {
segment.append(each);
} else {
result.add(segment.toString().trim());
segment.setLength(0);
}
break;
case '$':
if ('{' == inlineExpression.charAt(i + 1)) {
bracketsDepth++;
}
segment.append(each);
break;
case '}':
if (bracketsDepth > 0) {
bracketsDepth--;
}
segment.append(each);
break;
default:
segment.append(each);
break;
}
}
if (segment.length() > 0) {
result.add(segment.toString().trim());
}
return result;
}
private List<String> flattenSegments(final List<Object> segments) {
List<String> result = new ArrayList<>();
for (Object each : segments) {
if (each instanceof GString) {
result.addAll(assemblyCartesianSegments((GString) each));
} else {
result.add(each.toString());
}
}
return result;
}
private List<String> assemblyCartesianSegments(final GString segment) {
Set<List<String>> cartesianValues = getCartesianValues(segment);
List<String> result = new ArrayList<>(cartesianValues.size());
for (List<String> each : cartesianValues) {
result.add(assemblySegment(each, segment));
}
return result;
}
private String assemblySegment(final List<String> cartesianValue, final GString segment) {
StringBuilder result = new StringBuilder();
for (int i = 0; i < segment.getStrings().length; i++) {
result.append(segment.getStrings()[i]);
if (i < cartesianValue.size()) {
result.append(cartesianValue.get(i));
}
}
return result.toString();
}
@SuppressWarnings("unchecked")
private Set<List<String>> getCartesianValues(final GString segment) {
List<Set<String>> result = new ArrayList<>(segment.getValues().length);
for (Object each : segment.getValues()) {
if (null == each) {
continue;
}
if (each instanceof Collection) {
result.add(Sets.newHashSet(Collections2.transform((Collection<Object>) each, new Function<Object, String>() {
@Override
public String apply(final Object input) {
return input.toString();
}
})));
} else {
result.add(Sets.newHashSet(each.toString()));
}
}
return Sets.cartesianProduct(result);
}
}