/*
 * Copyright 2002-2015 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
 *
 *      https://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.springframework.transaction.interceptor;

import java.io.Serializable;

import org.springframework.util.Assert;

/**
 * Rule determining whether or not a given exception (and any subclasses)
 * should cause a rollback.
 *
 * <p>Multiple such rules can be applied to determine whether a transaction
 * should commit or rollback after an exception has been thrown.
 *
 * @author Rod Johnson
 * @since 09.04.2003
 * @see NoRollbackRuleAttribute
 */
@SuppressWarnings("serial")
public class RollbackRuleAttribute implements Serializable{

        /**
         * The {@link RollbackRuleAttribute rollback rule} for
         * {@link RuntimeException RuntimeExceptions}.
         */
        public static final RollbackRuleAttribute ROLLBACK_ON_RUNTIME_EXCEPTIONS =
                        new RollbackRuleAttribute(RuntimeException.class);


        /**
         * Could hold exception, resolving class name but would always require FQN.
         * This way does multiple string comparisons, but how often do we decide
         * whether to roll back a transaction following an exception?
         */
        private final String exceptionName;


        /**
         * Create a new instance of the {@code RollbackRuleAttribute} class.
         * <p>This is the preferred way to construct a rollback rule that matches
         * the supplied {@link Exception} class (and subclasses).
         * @param clazz throwable class; must be {@link Throwable} or a subclass
         * of {@code Throwable}
         * @throws IllegalArgumentException if the supplied {@code clazz} is
         * not a {@code Throwable} type or is {@code null}
         */
        public RollbackRuleAttribute(Class<?> clazz) {
                Assert.notNull(clazz, "'clazz' cannot be null");
                if (!Throwable.class.isAssignableFrom(clazz)) {
                        throw new IllegalArgumentException(
                                        "Cannot construct rollback rule from [" + clazz.getName() + "]: it's not a Throwable");
                }
                this.exceptionName = clazz.getName();
        }

        /**
         * Create a new instance of the {@code RollbackRuleAttribute} class
         * for the given {@code exceptionName}.
         * <p>This can be a substring, with no wildcard support at present. A value
         * of "ServletException" would match
         * {@code javax.servlet.ServletException} and subclasses, for example.
         * <p><b>NB:</b> Consider carefully how specific the pattern is, and
         * whether to include package information (which is not mandatory). For
         * example, "Exception" will match nearly anything, and will probably hide
         * other rules. "java.lang.Exception" would be correct if "Exception" was
         * meant to define a rule for all checked exceptions. With more unusual
         * exception names such as "BaseBusinessException" there's no need to use a
         * fully package-qualified name.
         * @param exceptionName the exception name pattern; can also be a fully
         * package-qualified class name
         * @throws IllegalArgumentException if the supplied
         * {@code exceptionName} is {@code null} or empty
         */
        public RollbackRuleAttribute(String exceptionName) {
                Assert.hasText(exceptionName, "'exceptionName' cannot be null or empty");
                this.exceptionName = exceptionName;
        }


        /**
         * Return the pattern for the exception name.
         */
        public String getExceptionName() {
                return exceptionName;
        }

        /**
         * Return the depth of the superclass matching.
         * <p>{@code 0} means {@code ex} matches exactly. Returns
         * {@code -1} if there is no match. Otherwise, returns depth with the
         * lowest depth winning.
         */
        public int getDepth(Throwable ex) {
                return getDepth(ex.getClass(), 0);
        }


        private int getDepth(Class<?> exceptionClass, int depth) {
                if (exceptionClass.getName().contains(this.exceptionName)) {
                        // Found it!
                        return depth;
                }
                // If we've gone as far as we can go and haven't found it...
                if (exceptionClass == Throwable.class) {
                        return -1;
                }
                return getDepth(exceptionClass.getSuperclass(), depth + 1);
        }


        @Override
        public boolean equals(Object other) {
                if (this == other) {
                        return true;
                }
                if (!(other instanceof RollbackRuleAttribute)) {
                        return false;
                }
                RollbackRuleAttribute rhs = (RollbackRuleAttribute) other;
                return this.exceptionName.equals(rhs.exceptionName);
        }

        @Override
        public int hashCode() {
                return this.exceptionName.hashCode();
        }

        @Override
        public String toString() {
                return "RollbackRuleAttribute with pattern [" + this.exceptionName + "]";
        }

}