/*
* 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.jclouds.rest;
import static com.google.common.base.Preconditions.checkNotNull;
import java.util.List;
import javax.inject.Inject;
import org.jclouds.predicates.Validator;
import org.jclouds.reflect.Invocation;
import org.jclouds.rest.annotations.ParamValidators;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.reflect.Parameter;
import com.google.inject.Injector;
/**
* Validates method parameters.
*
* Checks the {@link ParamValidators} annotation for validators. There can be method-level validators that apply to all
* parameters, and parameter-level validators. When validation on at least one parameter doesn't pass, throws
* {@link IllegalStateException}.
*
* @author Oleksiy Yarmula
*/
public class InputParamValidator {
private final Injector injector;
@Inject
public InputParamValidator(Injector injector) {
this.injector = injector;
}
public InputParamValidator() {
injector = null;
}
/**
* Validates that method parameters are correct, according to {@link ParamValidators}.
*
* @param method
* method with optionally set {@link ParamValidators}
* @param args
* method arguments with optionally set {@link ParamValidators}
* @see ParamValidators
* @see Validator
*
* @throws IllegalStateException
* if validation failed
*/
public void validateMethodParametersOrThrow(Invocation invocation) {
try {
performMethodValidation(checkNotNull(invocation, "invocation"));
performParameterValidation(invocation);
} catch (IllegalArgumentException e) {
throw new IllegalArgumentException(String.format("Validation on '%s' didn't pass:%n Reason: %s.", invocation,
e.getMessage()), e);
}
}
/**
* Returns if all the method parameters passed all of the method-level validators or throws an
* {@link IllegalArgumentException}.
*
* @param method
* method with optionally set {@link ParamValidators}. This can not be null.
* @param args
* method's parameters
*/
private void performMethodValidation(Invocation invocation) {
ParamValidators paramValidatorsAnnotation = invocation.getInvokable().getAnnotation(ParamValidators.class);
if (paramValidatorsAnnotation == null)
return; // by contract
List<Validator<?>> methodValidators = getValidatorsFromAnnotation(paramValidatorsAnnotation);
runPredicatesAgainstArgs(methodValidators, invocation.getArgs());
}
/**
* Returns if all the method parameters passed all of their corresponding validators or throws an
* {@link IllegalArgumentException}.
*
* @param parameters
* annotations for method's arguments
* @param args
* arguments that correspond to the array of annotations
*/
private void performParameterValidation(Invocation invocation) {
for (Parameter param : invocation.getInvokable().getParameters()) {
ParamValidators annotation = param.getAnnotation(ParamValidators.class);
if (annotation == null)
continue;
List<Validator<?>> parameterValidators = getValidatorsFromAnnotation(annotation);
// TODO position guava issue 1243
runPredicatesAgainstArg(parameterValidators, invocation.getArgs().get(param.hashCode()));
}
}
private List<Validator<?>> getValidatorsFromAnnotation(ParamValidators paramValidatorsAnnotation) {
List<Validator<?>> validators = Lists.newArrayList();
for (Class<? extends Validator<?>> validator : paramValidatorsAnnotation.value()) {
validators.add(checkNotNull(injector.getInstance(validator)));
}
return validators;
}
@SuppressWarnings("unchecked")
private void runPredicatesAgainstArg(List<Validator<?>> predicates, Object arg) {
for (@SuppressWarnings("rawtypes")
Validator validator : predicates) {
validator.apply(arg);
}
}
@SuppressWarnings("unchecked")
private void runPredicatesAgainstArgs(List<Validator<?>> predicates, List<Object> args) {
for (@SuppressWarnings("rawtypes")
Validator validator : predicates) {
Iterables.all(args, validator);
}
}
}