trunk/main/src/main/java/org/apache/jsieve/commands/AbstractConditionalCommand.java

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package org.apache.jsieve.commands;

import org.apache.jsieve.Block;
import org.apache.jsieve.ConditionManager;
import org.apache.jsieve.SieveContext;
import org.apache.jsieve.exception.SieveException;
import org.apache.jsieve.mail.MailAdapter;

/**
 * Abstract class AbstractConditionalCommand defines a framework of common
 * behavior for conditional Commands (if, elsif, else). Conditional commands use
 * a ConditionManager to relate and validate Commands within their Blocks.
 */
public abstract class AbstractConditionalCommand extends AbstractControlCommand {

    /**
     * Constructor for AbstractConditionalCommand.
     */
    public AbstractConditionalCommand() {
        super();
    }

    /**
     * Method execute executes a Block within the context of a new
     * ConditionManager.
     * 
     * @param mail not null
     * @param block not null
     * @param context not null
     * @return Object 
     * @throws SieveException
     */
    protected Object execute(MailAdapter mail, Block block, SieveContext context)
            throws SieveException {
        // Switch to a new ConditionManager
        ConditionManager oldManager = context.getConditionManager();
        context.setConditionManager(new ConditionManager());

        try {
            // Execute the Block
            Object result = block.execute(mail, context);
            return result;
        } finally {
            // Always restore the old ConditionManager
            context.setConditionManager(oldManager);
        }
    }

    /**
     * @see org.apache.jsieve.commands.AbstractCommand#validateBlock(Block,
     *      SieveContext)
     */
    protected void validateBlock(Block block, SieveContext context)
            throws SieveException {
        if (null == block)
            throw context.getCoordinate().syntaxException("Expecting a Block.");
    }

}