com.interface21.transaction.interceptor.RuleBasedTransactionAttribute.java Source code

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Here is the source code for com.interface21.transaction.interceptor.RuleBasedTransactionAttribute.java

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/*
 * The Spring Framework is published under the terms
 * of the Apache Software License.
 */

package com.interface21.transaction.interceptor;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * TransactionAttribute implementation that works out whether a 
 * given exception should cause transaction rollback by applying
 * a number of rollback rules, both positive and negative.
 * If no rules are relevant to the exception, it behaves
 * like DefaultTransactionAttribute (rolling back on
 * runtime exceptions).
 * <br>
 * The TransactionAttributeEditor property editor creates objects
 * of this class.
 * @since 09-Apr-2003
 * @version $Id: RuleBasedTransactionAttribute.java,v 1.3 2003/07/31 18:09:48 jhoeller Exp $
 * @author Rod Johnson
 */
public class RuleBasedTransactionAttribute extends DefaultTransactionAttribute {

    protected final Log logger = LogFactory.getLog(getClass());

    private List rollbackRules;

    public RuleBasedTransactionAttribute() {
        this.rollbackRules = new ArrayList();
    }

    public RuleBasedTransactionAttribute(int propagationBehavior, List rollbackRules) {
        super(propagationBehavior);
        this.rollbackRules = rollbackRules;
    }

    public void setRollbackRules(List rollbackRules) {
        this.rollbackRules = rollbackRules;
    }

    public List getRollbackRules() {
        return rollbackRules;
    }

    /**
     * Winning rule is the shallowest rule (that is, the closest
     * in the inheritance hierarchy to the exception). If no rule applies (-1),
     * return false.
     * @see com.interface21.transaction.interceptor.TransactionAttribute#rollbackOn(java.lang.Throwable)
     */
    public boolean rollbackOn(Throwable t) {
        logger.debug("Applying rules to determine whether transaction should rollback on " + t);
        RollbackRuleAttribute winner = null;
        int deepest = Integer.MAX_VALUE;

        if (this.rollbackRules != null) {
            for (Iterator iter = this.rollbackRules.iterator(); iter.hasNext();) {
                Object next = iter.next();
                // Ignore elements of unknown type
                if (next instanceof RollbackRuleAttribute) {
                    RollbackRuleAttribute rule = (RollbackRuleAttribute) next;
                    int depth = rule.getDepth(t);
                    if (depth >= 0 && depth < deepest) {
                        deepest = depth;
                        winner = rule;
                    }
                }
            }
        }
        logger.debug("Winning rollback rule is: " + winner);

        // User superclass behaviour (rollback on unchecked)
        // if no rule matches
        if (winner == null) {
            logger.debug("No relevant rollback rule found: applying superclass default");
            return super.rollbackOn(t);
        }

        return !(winner instanceof NoRollbackRuleAttribute);
    }

}