org.spearce.egit.core/src/org/spearce/egit/core/internal/util/ExceptionCollector.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2006 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package org.spearce.egit.core.internal.util;
  12
  13 import java.util.ArrayList;
  14 import java.util.Iterator;
  15 import java.util.List;
  16
  17 import org.eclipse.core.runtime.CoreException;
  18 import org.eclipse.core.runtime.ILog;
  19 import org.eclipse.core.runtime.IStatus;
  20 import org.eclipse.core.runtime.MultiStatus;
  21 import org.eclipse.core.runtime.Status;
  22
  23 /**
  24  * Collects exceptions and can be configured to ignore duplicates exceptions.
  25  * Exceptions can be logged and a MultiStatus containing all collected
  26  * exceptions can be returned.
  27  *
  28  * @see org.eclipse.core.runtime.MultiStatus
  29  * @see org.eclipse.core.runtime.IStatus
  30  *
  31  * @since 3.0
  32  */
  33 public class ExceptionCollector {
  34
  35         private final List<IStatus> statuses = new ArrayList<IStatus>();
  36
  37         private final String message;
  38
  39         private final String pluginId;
  40
  41         private final int severity;
  42
  43         private final ILog log;
  44
  45         /**
  46          * Creates a collector and initializes the parameters for the top-level
  47          * exception that would be returned from <code>getStatus</code> is
  48          * exceptions are collected.
  49          *
  50          * @param message
  51          *            a human-readable message, localized to the current locale
  52          * @param pluginId
  53          *            the unique identifier of the relevant plug-in
  54          * @param severity
  55          *            the severity; one of <code>OK</code>, <code>ERROR</code>,
  56          *            <code>INFO</code>, or <code>WARNING</code>
  57          * @param log
  58          *            the log to output the exceptions to, or <code>null</code> if
  59          *            exceptions should not be logged.
  60          */
  61         public ExceptionCollector(String message, String pluginId, int severity,
  62                         ILog log) {
  63                 this.message = message;
  64                 this.pluginId = pluginId;
  65                 this.severity = severity;
  66                 this.log = log;
  67         }
  68
  69         /**
  70          * Clears the exceptions collected.
  71          */
  72         public void clear() {
  73                 statuses.clear();
  74         }
  75
  76         /**
  77          * Returns a status that represents the exceptions collected. If the
  78          * collector is empty <code>IStatus.OK</code> is returned. Otherwise a
  79          * MultiStatus containing all collected exceptions is returned.
  80          *
  81          * @return a multistatus containing the exceptions collected or IStatus.OK
  82          *         if the collector is empty.
  83          */
  84         public IStatus getStatus() {
  85                 if (statuses.isEmpty()) {
  86                         return Status.OK_STATUS;
  87                 } else {
  88                         final MultiStatus multiStatus = new MultiStatus(pluginId, severity,
  89                                         message, null);
  90                         final Iterator it = statuses.iterator();
  91                         while (it.hasNext()) {
  92                                 final IStatus status = (IStatus) it.next();
  93                                 multiStatus.merge(status);
  94                         }
  95                         return multiStatus;
  96                 }
  97         }
  98
  99         /**
 100          * Add this exception to the collector. If a log was specified in the
 101          * constructor then the exception will be output to the log. You can
 102          * retreive exceptions using <code>getStatus</code>.
 103          *
 104          * @param exception
 105          *            the exception to collect
 106          */
 107         public void handleException(CoreException exception) {
 108                 if (log != null) {
 109                         log.log(new Status(severity, pluginId, 0, message, exception));
 110                 }
 111
 112                 // Record each status individually to flatten the resulting multi-status
 113                 final IStatus exceptionStatus = exception.getStatus();
 114
 115                 // Wrap the exception so the stack trace is not lost.
 116                 final IStatus status = new Status(exceptionStatus.getSeverity(),
 117                                 exceptionStatus.getPlugin(), exceptionStatus.getCode(),
 118                                 exceptionStatus.getMessage(), exception);
 119
 120                 recordStatus(status);
 121                 for (IStatus childStatus : status.getChildren())
 122                         recordStatus(childStatus);
 123         }
 124
 125         private void recordStatus(IStatus status) {
 126                 statuses.add(status);
 127         }
 128 }