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19  
20  package org.apache.jsieve.commands;
21  
22  import org.apache.jsieve.Block;
23  import org.apache.jsieve.ConditionManager;
24  import org.apache.jsieve.SieveContext;
25  import org.apache.jsieve.exception.SieveException;
26  import org.apache.jsieve.mail.MailAdapter;
27  
28  /**
29   * Abstract class AbstractConditionalCommand defines a framework of common
30   * behavior for conditional Commands (if, elsif, else). Conditional commands use
31   * a ConditionManager to relate and validate Commands within their Blocks.
32   */
33  public abstract class AbstractConditionalCommand extends AbstractControlCommand {
34  
35      /**
36       * Constructor for AbstractConditionalCommand.
37       */
38      public AbstractConditionalCommand() {
39          super();
40      }
41  
42      /**
43       * Method execute executes a Block within the context of a new
44       * ConditionManager.
45       * 
46       * @param mail not null
47       * @param block not null
48       * @param context not null
49       * @return Object 
50       * @throws SieveException
51       */
52      protected Object execute(MailAdapter mail, Block block, SieveContext context)
53              throws SieveException {
54          // Switch to a new ConditionManager
55          ConditionManager oldManager = context.getConditionManager();
56          context.setConditionManager(new ConditionManager());
57  
58          try {
59              // Execute the Block
60              Object result = block.execute(mail, context);
61              return result;
62          } finally {
63              // Always restore the old ConditionManager
64              context.setConditionManager(oldManager);
65          }
66      }
67  
68      /**
69       * @see org.apache.jsieve.commands.AbstractCommand#validateBlock(Block,
70       *      SieveContext)
71       */
72      protected void validateBlock(Block block, SieveContext context)
73              throws SieveException {
74          if (null == block)
75              throw context.getCoordinate().syntaxException("Expecting a Block.");
76      }
77  
78  }