| 1 | /** |
| 2 | * Licensed to jclouds, Inc. (jclouds) under one or more |
| 3 | * contributor license agreements. See the NOTICE file |
| 4 | * distributed with this work for additional information |
| 5 | * regarding copyright ownership. jclouds licenses this file |
| 6 | * to you under the Apache License, Version 2.0 (the |
| 7 | * "License"); you may not use this file except in compliance |
| 8 | * with the License. You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, |
| 13 | * software distributed under the License is distributed on an |
| 14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | * KIND, either express or implied. See the License for the |
| 16 | * specific language governing permissions and limitations |
| 17 | * under the License. |
| 18 | */ |
| 19 | package org.jclouds.rest; |
| 20 | |
| 21 | import static com.google.common.base.Preconditions.checkNotNull; |
| 22 | |
| 23 | import java.lang.annotation.Annotation; |
| 24 | import java.lang.reflect.Method; |
| 25 | import java.util.Arrays; |
| 26 | import java.util.List; |
| 27 | |
| 28 | import javax.inject.Inject; |
| 29 | |
| 30 | import org.jclouds.predicates.Validator; |
| 31 | import org.jclouds.rest.annotations.ParamValidators; |
| 32 | |
| 33 | import com.google.common.collect.Iterables; |
| 34 | import com.google.common.collect.Lists; |
| 35 | import com.google.inject.Injector; |
| 36 | |
| 37 | /** |
| 38 | * Validates method parameters. |
| 39 | * |
| 40 | * Checks the {@link ParamValidators} annotation for validators. There can be method-level |
| 41 | * validators that apply to all parameters, and parameter-level validators. When validation on at |
| 42 | * least one parameter doesn't pass, throws {@link IllegalStateException}. |
| 43 | * |
| 44 | * @author Oleksiy Yarmula |
| 45 | */ |
| 46 | public class InputParamValidator { |
| 47 | |
| 48 | private final Injector injector; |
| 49 | |
| 50 | @Inject |
| 51 | public InputParamValidator(Injector injector) { |
| 52 | this.injector = injector; |
| 53 | } |
| 54 | |
| 55 | public InputParamValidator() { |
| 56 | injector = null; |
| 57 | } |
| 58 | |
| 59 | /** |
| 60 | * Validates that method parameters are correct, according to {@link ParamValidators}. |
| 61 | * |
| 62 | * @param method |
| 63 | * method with optionally set {@link ParamValidators} |
| 64 | * @param args |
| 65 | * method arguments with optionally set {@link ParamValidators} |
| 66 | * @see ParamValidators |
| 67 | * @see Validator |
| 68 | * |
| 69 | * @throws IllegalStateException |
| 70 | * if validation failed |
| 71 | */ |
| 72 | public void validateMethodParametersOrThrow(Method method, Object... args) { |
| 73 | |
| 74 | try { |
| 75 | performMethodValidation(method, args); |
| 76 | performParameterValidation(method.getParameterAnnotations(), args); |
| 77 | } catch(IllegalArgumentException e) { |
| 78 | String argsString = Iterables.toString(Arrays.asList(args)); |
| 79 | throw new IllegalArgumentException(String.format("Validation on '%s#%s' didn't pass for arguments: " + |
| 80 | "%s. %n Reason: %s.", method.getDeclaringClass().getName(), method.getName(), argsString, |
| 81 | e.getMessage())); |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | /** |
| 86 | * Returns if all the method parameters passed all of the method-level |
| 87 | * validators or throws an {@link IllegalArgumentException}. |
| 88 | * @param method |
| 89 | * method with optionally set {@link ParamValidators}. This can not be null. |
| 90 | * @param args |
| 91 | * method's parameters |
| 92 | */ |
| 93 | private void performMethodValidation(Method method, Object... args) { |
| 94 | ParamValidators paramValidatorsAnnotation = checkNotNull(method).getAnnotation( |
| 95 | ParamValidators.class); |
| 96 | if (paramValidatorsAnnotation == null) |
| 97 | return; // by contract |
| 98 | |
| 99 | List<Validator<?>> methodValidators = getValidatorsFromAnnotation(paramValidatorsAnnotation); |
| 100 | |
| 101 | runPredicatesAgainstArgs(methodValidators, args); |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Returns if all the method parameters passed all of their corresponding |
| 106 | * validators or throws an {@link IllegalArgumentException}. |
| 107 | * |
| 108 | * @param annotations |
| 109 | * annotations for method's arguments |
| 110 | * @param args |
| 111 | * arguments that correspond to the array of annotations |
| 112 | */ |
| 113 | private void performParameterValidation(Annotation[][] annotations, Object... args) { |
| 114 | for (int currentParameterIndex = 0; currentParameterIndex < annotations.length; currentParameterIndex++) { |
| 115 | ParamValidators annotation = findParamValidatorsAnnotationOrReturnNull(annotations[currentParameterIndex]); |
| 116 | if (annotation == null) |
| 117 | continue; |
| 118 | List<Validator<?>> parameterValidators = getValidatorsFromAnnotation(annotation); |
| 119 | runPredicatesAgainstArgs(parameterValidators, |
| 120 | args[currentParameterIndex]); |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | private List<Validator<?>> getValidatorsFromAnnotation(ParamValidators paramValidatorsAnnotation) { |
| 125 | List<Validator<?>> validators = Lists.newArrayList(); |
| 126 | for (Class<? extends Validator<?>> validator : paramValidatorsAnnotation.value()) { |
| 127 | validators.add(checkNotNull(injector.getInstance(validator))); |
| 128 | } |
| 129 | return validators; |
| 130 | } |
| 131 | |
| 132 | @SuppressWarnings("unchecked") |
| 133 | private void runPredicatesAgainstArgs(List<Validator<?>> predicates, Object... args) { |
| 134 | for (@SuppressWarnings("rawtypes") Validator validator : predicates) { |
| 135 | Iterables.all(Arrays.asList(args), validator); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | private ParamValidators findParamValidatorsAnnotationOrReturnNull( |
| 140 | Annotation[] parameterAnnotations) { |
| 141 | for (Annotation annotation : parameterAnnotations) { |
| 142 | if (annotation instanceof ParamValidators) |
| 143 | return (ParamValidators) annotation; |
| 144 | } |
| 145 | return null; |
| 146 | } |
| 147 | |
| 148 | } |