/*
* Copyright 2011 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 com.jayway.jaxrs.hateoas.support;
import com.google.common.base.Function;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterators;
import com.google.common.collect.Lists;
import com.jayway.jaxrs.hateoas.HateoasInjectException;
import com.jayway.jaxrs.hateoas.HateoasLinkInjector;
import com.jayway.jaxrs.hateoas.HateoasVerbosity;
import com.jayway.jaxrs.hateoas.LinkProducer;
import org.apache.commons.lang.StringUtils;
import java.lang.reflect.Field;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
/**
* @author Mattias Hellborg Arthursson
*/
public class FieldPath implements Iterable<String> {
public final static FieldPath EMPTY_PATH = new FieldPath(Collections.<String>emptyList());
private final Collection<String> path;
private FieldPath(Collection<String> path) {
this.path = path;
for (String s : path) {
if (StringUtils.isBlank(s)) {
throw new IllegalArgumentException("Blank elements in field path are not allowed");
}
}
}
public static FieldPath path(String path) {
String[] pathElement = path.split("\\.");
return new FieldPath(Arrays.asList(pathElement));
}
@Override
public Iterator<String> iterator() {
return path.iterator();
}
public Object injectLinks(Object target, HateoasLinkInjector<Object> injector, LinkProducer linkProducer,
HateoasVerbosity verbosity) {
if (target == null) {
return target;
}
try {
return injectLinks(iterator(), target, injector, linkProducer, verbosity);
} catch (Exception e) {
throw new HateoasInjectException(e);
}
}
@SuppressWarnings("unchecked")
private Object injectLinks(Iterator<String> pathIterator, Object currentTarget,
final HateoasLinkInjector<Object> injector, final LinkProducer linkProducer,
final HateoasVerbosity verbosity) throws NoSuchFieldException, IllegalAccessException {
if (currentTarget == null) {
return currentTarget;
}
if (!pathIterator.hasNext()) {
if (Collection.class.isAssignableFrom(currentTarget.getClass())) {
Collection<Object> targetAsCollection = (Collection<Object>) currentTarget;
return Collections2.transform(targetAsCollection, new Function<Object, Object>() {
@Override
public Object apply(Object entry) {
return injector.injectLinks(entry, linkProducer, verbosity);
}
});
}
return injector.injectLinks(currentTarget, linkProducer, verbosity);
}
String currentFieldName = pathIterator.next();
Field currentField = ReflectionUtils.getField(currentTarget, currentFieldName);
Object nextTarget = currentField.get(currentTarget);
Object nextResult = null;
if (nextTarget != null && Collection.class.isAssignableFrom(nextTarget.getClass())) {
// We have not yet arrived at the end of the FieldPath, and the object at the current position in the
// path is a Collection - the rest of the path should be traversed for _each_ if the items in the
// collection.
final ImmutableList<String> restOfPath = ImmutableList.copyOf(pathIterator);
Collection<Object> targetAsCollection = (Collection<Object>) nextTarget;
nextResult = Collections2.transform(targetAsCollection, new Function<Object, Object>() {
@Override
public Object apply(Object entry) {
FieldPath nestedPath = new FieldPath(restOfPath);
return nestedPath.injectLinks(entry, injector, linkProducer, verbosity);
}
});
} else {
nextResult = injectLinks(pathIterator, nextTarget, injector, linkProducer, verbosity);
}
currentField.set(currentTarget, nextResult);
return currentTarget;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
FieldPath fieldPath = (FieldPath) o;
if (path != null ? !path.equals(fieldPath.path) : fieldPath.path != null) return false;
return true;
}
@Override
public int hashCode() {
return path != null ? path.hashCode() : 0;
}
}