org.glowroot.advicegen.PathEvaluator Maven / Gradle / Ivy
/*
* Copyright 2014-2015 the original author or authors.
*
* 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.
*/
package org.glowroot.advicegen;
import java.util.List;
import javax.annotation.Nullable;
import org.glowroot.shaded.google.common.base.Splitter;
import org.glowroot.shaded.google.common.collect.Lists;
class PathEvaluator {
private static final Splitter splitter = Splitter.on('.').omitEmptyStrings();
private final Accessor[] accessors;
private final String /*@Nullable*/[] remainingPath;
PathEvaluator(Class baseClass, String path) {
List parts = Lists.newArrayList(splitter.split(path));
List accessors = Lists.newArrayList();
Class currClass = baseClass;
while (!parts.isEmpty()) {
String currPart = parts.remove(0);
Accessor accessor = Beans.loadPossiblyArrayBasedAccessor(currClass, currPart);
if (accessor == null) {
parts.add(0, currPart);
break;
}
accessors.add(accessor);
currClass = accessor.getValueType();
}
this.accessors = accessors.toArray(new Accessor[accessors.size()]);
if (parts.isEmpty()) {
remainingPath = null;
} else {
remainingPath = parts.toArray(new String[parts.size()]);
}
}
@Nullable
Object evaluateOnBase(Object base) throws Exception {
Object curr = base;
for (Accessor accessor : accessors) {
curr = accessor.evaluate(curr);
if (curr == null) {
return null;
}
}
if (remainingPath != null) {
// too bad, revert to slow Beans
return Beans.value(curr, remainingPath);
}
return curr;
}
}