| /******************************************************************************* |
| * 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.apache.sling.scripting.sightly.use; |
| |
| /** |
| * Result returned by a {@link UseProvider}. |
| */ |
| public final class ProviderOutcome { |
| |
| // a generic failure without a cause returned by #failure() |
| private static final ProviderOutcome GENERIC_FAILURE = new ProviderOutcome(false, null, null); |
| |
| // whether this is a success or failure |
| private final boolean success; |
| |
| // the result value in case of success (may be null) |
| private final Object result; |
| |
| // the reason for failure in case of failure (may be null) |
| private final Throwable cause; |
| |
| /** |
| * Creates an outcome instance |
| * |
| * @param success {@code true} to indicate success or {@code false} to indicate failure |
| * @param result optional result value in case of success, may be {@code null} |
| * @param cause optional cause in case of failure, may be {@code null} |
| */ |
| private ProviderOutcome(boolean success, Object result, Throwable cause) { |
| this.success = success; |
| this.result = result; |
| this.cause = cause; |
| } |
| |
| /** |
| * Create a successful outcome |
| * |
| * @param result the result |
| * @return a successful result |
| */ |
| public static ProviderOutcome success(Object result) { |
| return new ProviderOutcome(true, result, null); |
| } |
| |
| /** |
| * Create a failed outcome without a specific {@link #getCause() cause}. This method must be used for creating outcomes that don't |
| * signal an error but rather the fact that the {@link UseProvider} is not capable of fulfilling the request. |
| * |
| * @return a failed outcome |
| */ |
| public static ProviderOutcome failure() { |
| return GENERIC_FAILURE; |
| } |
| |
| /** |
| * Create a failed outcome with the given {@link #getCause() cause}. This method must be used when the {@link UseProvider} is |
| * capable of fulfilling the request but an error condition prevents the provider from doing so. |
| * |
| * @param cause The reason for this failure, which may be {@code null} |
| * @return a failed outcome |
| */ |
| public static ProviderOutcome failure(Throwable cause) { |
| return new ProviderOutcome(false, null, cause); |
| } |
| |
| /** |
| * If the given obj is not {@code null} return a {@link #success(Object) successful outcome}, with the given result. Otherwise, return |
| * {@link #failure()}. |
| * |
| * @param obj the result |
| * @return an outcome based on whether the parameter is null or not |
| */ |
| public static ProviderOutcome notNullOrFailure(Object obj) { |
| return (obj == null) ? failure() : success(obj); |
| } |
| |
| /** |
| * Check if the outcome has been successful |
| * |
| * @return the outcome success status |
| */ |
| public boolean isSuccess() { |
| return success; |
| } |
| |
| /** |
| * Check whether the outcome is a failure |
| * |
| * @return the outcome failure status |
| */ |
| public boolean isFailure() { |
| return !isSuccess(); |
| } |
| |
| /** |
| * Get the result in this outcome. |
| * |
| * @return the result of the container |
| * @throws IllegalStateException if the outcome is a failure |
| */ |
| public Object getResult() { |
| if (!success) { |
| throw new IllegalStateException("Outcome has not been successful"); |
| } |
| return result; |
| } |
| |
| /** |
| * Returns the cause for this failure outcome or {@code null} if this outcome is a success or no cause has been defined with the |
| * {@link #failure(Throwable)} method. |
| * |
| * @return the cause for this failure outcome. |
| */ |
| public Throwable getCause() { |
| return cause; |
| } |
| } |