gerrit-server/src/main/java/com/google/gerrit/server/mail/OutgoingEmail.java - gerrit - Git at Google

 // Copyright (C) 2009 The Android Open Source Project
 //
 // 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
 //
 // http://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 com.google.gerrit.server.mail;

 import com.google.gerrit.reviewdb.Account;
 import com.google.gerrit.reviewdb.AccountGroup;
 import com.google.gerrit.reviewdb.AccountProjectWatch;
 import com.google.gerrit.reviewdb.Change;
 import com.google.gerrit.reviewdb.ChangeMessage;
 import com.google.gerrit.reviewdb.PatchSet;
 import com.google.gerrit.reviewdb.PatchSetApproval;
 import com.google.gerrit.reviewdb.PatchSetInfo;
 import com.google.gerrit.reviewdb.ReviewDb;
 import com.google.gerrit.reviewdb.StarredChange;
 import com.google.gerrit.reviewdb.UserIdentity;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.account.AccountCache;
 import com.google.gerrit.server.config.CanonicalWebUrl;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.patch.PatchList;
 import com.google.gerrit.server.patch.PatchListCache;
 import com.google.gerrit.server.patch.PatchListEntry;
 import com.google.gerrit.server.patch.PatchSetInfoFactory;
 import com.google.gerrit.server.patch.PatchSetInfoNotAvailableException;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gwtorm.client.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;

 import org.eclipse.jgit.util.SystemReader;

 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Date;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
 import java.util.Set;

 import javax.annotation.Nullable;

 /** Sends an email to one or more interested parties. */
 public abstract class OutgoingEmail {
   private static final String HDR_TO = "To";
   private static final String HDR_CC = "CC";

   private static final Random RNG = new Random();
   private final String messageClass;
   protected final Change change;
   protected String projectName;
   private final HashSet<Account.Id> rcptTo = new HashSet<Account.Id>();
   private final Map<String, EmailHeader> headers;
   private final List<Address> smtpRcptTo = new ArrayList<Address>();
   private Address smtpFromAddress;
   private StringBuilder body;
   private boolean inFooter;

   protected Account.Id fromId;
   protected PatchSet patchSet;
   protected PatchSetInfo patchSetInfo;
   protected ChangeMessage changeMessage;
   protected ReviewDb db;

   @Inject
   protected GitRepositoryManager server;

   @Inject
   private ProjectCache projectCache;

   @Inject
   private AccountCache accountCache;

   @Inject
   private PatchListCache patchListCache;

   @Inject
   private FromAddressGenerator fromAddressGenerator;

   @Inject
   private EmailSender emailSender;

   @Inject
   private PatchSetInfoFactory patchSetInfoFactory;

   @Inject
   private IdentifiedUser.GenericFactory identifiedUserFactory;

   @Inject
   @CanonicalWebUrl
   @Nullable
   private Provider<String> urlProvider;

   private ProjectState projectState;

   protected OutgoingEmail(final Change c, final String mc) {
     change = c;
     messageClass = mc;
     headers = new LinkedHashMap<String, EmailHeader>();
   }

   protected OutgoingEmail(final String mc) {
     this(null, mc);
   }

   public void setFrom(final Account.Id id) {
     fromId = id;
   }

   public void setPatchSet(final PatchSet ps) {
     patchSet = ps;
   }

   public void setPatchSet(final PatchSet ps, final PatchSetInfo psi) {
     patchSet = ps;
     patchSetInfo = psi;
   }

   public void setChangeMessage(final ChangeMessage cm) {
     changeMessage = cm;
   }

   public void setReviewDb(final ReviewDb d) {
     db = d;
   }

   /**
    * Format and enqueue the message for delivery.
    *
    * @throws EmailException
    */
   public void send() throws EmailException {
     if (!emailSender.isEnabled()) {
       // Server has explicitly disabled email sending.
       //
       return;
     }

     init();
     format();
     if (shouldSendMessage()) {
       if (fromId != null) {
         // If we are impersonating a user, make sure they receive a CC of
         // this message so they can always review and audit what we sent
         // on their behalf to others.
         //
         add(RecipientType.CC, fromId);
       }
       if (change != null) {
         if (getChangeUrl() != null) {
           openFooter();
           appendText("To view visit ");
           appendText(getChangeUrl());
           appendText("\n");
         }
         if (getSettingsUrl() != null) {
           openFooter();
           appendText("To unsubscribe, visit ");
           appendText(getSettingsUrl());
           appendText("\n");
         }

         if (inFooter) {
           appendText("\n");
         } else {
           openFooter();
         }
         appendText("Gerrit-MessageType: " + messageClass + "\n");
         appendText("Gerrit-Project: " + projectName + "\n");
         appendText("Gerrit-Branch: " + change.getDest().getShortName() + "\n");
       }

       if (headers.get("Message-ID").isEmpty()) {
         final StringBuilder rndid = new StringBuilder();
         rndid.append("<");
         rndid.append(System.currentTimeMillis());
         rndid.append("-");
         rndid.append(Integer.toString(RNG.nextInt(999999), 36));
         rndid.append("@");
         rndid.append(SystemReader.getInstance().getHostname());
         rndid.append(">");
         setHeader("Message-ID", rndid.toString());
       }

       emailSender.send(smtpFromAddress, smtpRcptTo, headers, body.toString());
     }
   }

   /** Format the message body by calling {@link #appendText(String)}. */
   protected abstract void format();

   /** Setup the message headers and envelope (TO, CC, BCC). */
   protected void init() {
     if (change != null && projectCache != null) {
       projectState = projectCache.get(change.getProject());
       projectName =
           projectState != null ? projectState.getProject().getName() : null;
     } else {
       projectState = null;
       projectName = null;
     }

     smtpFromAddress = fromAddressGenerator.from(fromId);
     if (changeMessage != null && changeMessage.getWrittenOn() != null) {
       setHeader("Date", new Date(changeMessage.getWrittenOn().getTime()));
     } else {
       setHeader("Date", new Date());
     }
     headers.put("From", new EmailHeader.AddressList(smtpFromAddress));
     headers.put(HDR_TO, new EmailHeader.AddressList());
     headers.put(HDR_CC, new EmailHeader.AddressList());
     if (change != null) {
       setChangeSubjectHeader();
     }
     setHeader("Message-ID", "");

     if (fromId != null) {
       // If we have a user that this message is supposedly caused by
       // but the From header on the email does not match the user as
       // it is a generic header for this Gerrit server, include the
       // Reply-To header with the current user's email address.
       //
       final Address a = toAddress(fromId);
       if (a != null && !smtpFromAddress.email.equals(a.email)) {
         setHeader("Reply-To", a.email);
       }
     }

     setHeader("X-Gerrit-MessageType", messageClass);
     if (change != null) {
       setHeader("X-Gerrit-Change-Id", "" + change.getKey().get());
       setListIdHeader();
       setChangeUrlHeader();
       setCommitIdHeader();
     }
     body = new StringBuilder();
     inFooter = false;

     if (fromId != null && fromAddressGenerator.isGenericAddress(fromId)) {
       final Account account = accountCache.get(fromId).getAccount();
       final String name = account.getFullName();
       final String email = account.getPreferredEmail();

       if ((name != null && !name.isEmpty())
           || (email != null && !email.isEmpty())) {
         body.append("From");
         if (name != null && !name.isEmpty()) {
           body.append(" ").append(name);
         }
         if (email != null && !email.isEmpty()) {
           body.append(" <").append(email).append(">");
         }
         body.append(":\n\n");
       }
     }

     if (change != null && db != null) {
       if (patchSet == null) {
         try {
           patchSet = db.patchSets().get(change.currentPatchSetId());
         } catch (OrmException err) {
           patchSet = null;
         }
       }

       if (patchSet != null && patchSetInfo == null) {
         try {
           patchSetInfo = patchSetInfoFactory.get(patchSet.getId());
         } catch (PatchSetInfoNotAvailableException err) {
           patchSetInfo = null;
         }
       }
     }
   }

   private void setListIdHeader() {
     // Set a reasonable list id so that filters can be used to sort messages
     //
     final StringBuilder listid = new StringBuilder();
     listid.append("gerrit-");
     listid.append(projectName.replace('/', '-'));
     listid.append("@");
     listid.append(getGerritHost());

     final String listidStr = listid.toString();
     setHeader("Mailing-List", "list " + listidStr);
     setHeader("List-Id", "<" + listidStr.replace('@', '.') + ">");
     if (getSettingsUrl() != null) {
       setHeader("List-Unsubscribe", "<" + getSettingsUrl() + ">");
     }
   }

   private void setChangeUrlHeader() {
     final String u = getChangeUrl();
     if (u != null) {
       setHeader("X-Gerrit-ChangeURL", "<" + u + ">");
     }
   }

   private void setCommitIdHeader() {
     if (patchSet != null && patchSet.getRevision() != null
         && patchSet.getRevision().get() != null
         && patchSet.getRevision().get().length() > 0) {
       setHeader("X-Gerrit-Commit", patchSet.getRevision().get());
     }
   }

   private void setChangeSubjectHeader() {
     final StringBuilder subj = new StringBuilder();
     subj.append("[");
     subj.append(change.getDest().getShortName());
     subj.append("] ");
     subj.append("Change ");
     subj.append(change.getKey().abbreviate());
     subj.append(": (");
     subj.append(projectName);
     subj.append(") ");
     if (change.getSubject().length() > 60) {
       subj.append(change.getSubject().substring(0, 60));
       subj.append("...");
     } else {
       subj.append(change.getSubject());
     }
     setHeader("Subject", subj.toString());
   }

   protected String getGerritHost() {
     if (getGerritUrl() != null) {
       try {
         return new URL(getGerritUrl()).getHost();
       } catch (MalformedURLException e) {
         // Try something else.
       }
     }

     // Fall back onto whatever the local operating system thinks
     // this server is called. We hopefully didn't get here as a
     // good admin would have configured the canonical url.
     //
     return SystemReader.getInstance().getHostname();
   }

   /** Get a link to the change; null if the server doesn't know its own address. */
   protected String getChangeUrl() {
     if (change != null && getGerritUrl() != null) {
       final StringBuilder r = new StringBuilder();
       r.append(getGerritUrl());
       r.append(change.getChangeId());
       return r.toString();
     }
     return null;
   }

   private String getSettingsUrl() {
     if (getGerritUrl() != null) {
       final StringBuilder r = new StringBuilder();
       r.append(getGerritUrl());
       r.append("settings");
       return r.toString();
     }
     return null;
   }

   protected String getGerritUrl() {
     return urlProvider.get();
   }

   protected String getChangeMessageThreadId() {
     final StringBuilder r = new StringBuilder();
     r.append('<');
     r.append("gerrit");
     r.append('.');
     r.append(change.getCreatedOn().getTime());
     r.append('.');
     r.append(change.getKey().get());
     r.append('@');
     r.append(getGerritHost());
     r.append('>');
     return r.toString();
   }

   /** Set a header in the outgoing message. */
   protected void setHeader(final String name, final String value) {
     headers.put(name, new EmailHeader.String(value));
   }

   protected void setHeader(final String name, final Date date) {
     headers.put(name, new EmailHeader.Date(date));
   }

   /** Append text to the outgoing email body. */
   protected void appendText(final String text) {
     if (text != null) {
       body.append(text);
     }
   }

   private void openFooter() {
     if (!inFooter) {
       inFooter = true;
       appendText("-- \n");
     }
   }

   /** Format the sender's "cover letter", {@link #getCoverLetter()}. */
   protected void formatCoverLetter() {
     final String cover = getCoverLetter();
     if (!"".equals(cover)) {
       appendText(cover);
       appendText("\n\n");
     }
   }

   /** Get the text of the "cover letter", from {@link ChangeMessage}. */
   protected String getCoverLetter() {
     if (changeMessage != null) {
       final String txt = changeMessage.getMessage();
       if (txt != null) {
         return txt.trim();
       }
     }
     return "";
   }

   /** Format the change message and the affected file list. */
   protected void formatChangeDetail() {
     if (patchSetInfo != null) {
       appendText(patchSetInfo.getMessage().trim());
       appendText("\n");
     } else {
       appendText(change.getSubject().trim());
       appendText("\n");
     }

     if (patchSet != null) {
       appendText("---\n");
       for (PatchListEntry p : getPatchList().getPatches()) {
         appendText(p.getChangeType().getCode() + " " + p.getNewName() + "\n");
       }
       appendText("\n");
     }
   }

   /** Get the patch list corresponding to this patch set. */
   protected PatchList getPatchList() {
     if (patchSet != null) {
       return patchListCache.get(change, patchSet);
     }
     return null;
   }

   /** Lookup a human readable name for an account, usually the "full name". */
   protected String getNameFor(final Account.Id accountId) {
     if (accountId == null) {
       return "Anonymous Coward";
     }

     final Account userAccount = accountCache.get(accountId).getAccount();
     String name = userAccount.getFullName();
     if (name == null) {
       name = userAccount.getPreferredEmail();
     }
     if (name == null) {
       name = "Anonymous Coward #" + accountId;
     }
     return name;
   }

   protected boolean shouldSendMessage() {
     if (body.length() == 0) {
       // If we have no message body, don't send.
       //
       return false;
     }

     if (rcptTo.isEmpty()) {
       // If we have nobody to send this message to, then all of our
       // selection filters previously for this type of message were
       // unable to match a destination. Don't bother sending it.
       //
       return false;
     }

     if (rcptTo.size() == 1 && rcptTo.contains(fromId)) {
       // If the only recipient is also the sender, don't bother.
       //
       return false;
     }

     return true;
   }

   /** Get the project entity the change is in; null if its been deleted. */
   protected ProjectState getProjectState() {
     return projectState;
   }

   /** Get the groups which own the project. */
   protected Set<AccountGroup.Id> getProjectOwners() {
     final ProjectState r;

     r = projectCache.get(change.getProject());
     return r != null ? r.getOwners() : Collections.<AccountGroup.Id> emptySet();
   }

   /** Schedule this message for delivery to the listed accounts. */
   protected void add(final RecipientType rt, final Collection<Account.Id> list) {
     for (final Account.Id id : list) {
       add(rt, id);
     }
   }

   /** TO or CC all vested parties (change owner, patch set uploader, author). */
   protected void rcptToAuthors(final RecipientType rt) {
     add(rt, change.getOwner());
     if (patchSet != null) {
       add(rt, patchSet.getUploader());
     }
     if (patchSetInfo != null) {
       add(rt, patchSetInfo.getAuthor());
       add(rt, patchSetInfo.getCommitter());
     }
   }

   private void add(final RecipientType rt, final UserIdentity who) {
     if (who != null && who.getAccount() != null) {
       add(rt, who.getAccount());
     }
   }

   /** BCC any user who has starred this change. */
   protected void bccStarredBy() {
     if (db != null) {
       try {
         // BCC anyone who has starred this change.
         //
         for (StarredChange w : db.starredChanges().byChange(change.getId())) {
           add(RecipientType.BCC, w.getAccountId());
         }
       } catch (OrmException err) {
         // Just don't BCC everyone. Better to send a partial message to those
         // we already have queued up then to fail deliver entirely to people
         // who have a lower interest in the change.
       }
     }
   }

   /** BCC any user who has set "notify all comments" on this project. */
   protected void bccWatchesNotifyAllComments() {
     if (db != null) {
       try {
         // BCC anyone else who has interest in this project's changes
         //
         final ProjectState ps = getProjectState();
         if (ps != null) {
           for (final AccountProjectWatch w : db.accountProjectWatches()
               .notifyAllComments(ps.getProject().getNameKey())) {
             add(RecipientType.BCC, w.getAccountId());
           }
         }
       } catch (OrmException err) {
         // Just don't CC everyone. Better to send a partial message to those
         // we already have queued up then to fail deliver entirely to people
         // who have a lower interest in the change.
       }
     }
   }

   /** Any user who has published comments on this change. */
   protected void ccAllApprovals() {
     ccApprovals(true);
   }

   /** Users who have non-zero approval codes on the change. */
   protected void ccExistingReviewers() {
     ccApprovals(false);
   }

   private void ccApprovals(final boolean includeZero) {
     if (db != null) {
       try {
         // CC anyone else who has posted an approval mark on this change
         //
         for (PatchSetApproval ap : db.patchSetApprovals().byChange(
             change.getId())) {
           if (!includeZero && ap.getValue() == 0) {
             continue;
           }
           add(RecipientType.CC, ap.getAccountId());
         }
       } catch (OrmException err) {
       }
     }
   }

   /** Schedule delivery of this message to the given account. */
   protected void add(final RecipientType rt, final Account.Id to) {
     if (!rcptTo.contains(to) && isVisibleTo(to)) {
       rcptTo.add(to);
       add(rt, toAddress(to));
     }
   }

   private boolean isVisibleTo(final Account.Id to) {
     return projectState == null
         || change == null
         || projectState.controlFor(identifiedUserFactory.create(to))
             .controlFor(change).isVisible();
   }

   /** Schedule delivery of this message to the given account. */
   protected void add(final RecipientType rt, final Address addr) {
     if (addr != null && addr.email != null && addr.email.length() > 0) {
       smtpRcptTo.add(addr);
       switch (rt) {
         case TO:
           ((EmailHeader.AddressList) headers.get(HDR_TO)).add(addr);
           break;
         case CC:
           ((EmailHeader.AddressList) headers.get(HDR_CC)).add(addr);
           break;
       }
     }
   }

   private Address toAddress(final Account.Id id) {
     final Account a = accountCache.get(id).getAccount();
     final String e = a.getPreferredEmail();
     if (e == null) {
       return null;
     }
     return new Address(a.getFullName(), e);
   }
 }
	// Copyright (C) 2009 The Android Open Source Project
	//
	// 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
	//
	// http://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 com.google.gerrit.server.mail;

	import com.google.gerrit.reviewdb.Account;
	import com.google.gerrit.reviewdb.AccountGroup;
	import com.google.gerrit.reviewdb.AccountProjectWatch;
	import com.google.gerrit.reviewdb.Change;
	import com.google.gerrit.reviewdb.ChangeMessage;
	import com.google.gerrit.reviewdb.PatchSet;
	import com.google.gerrit.reviewdb.PatchSetApproval;
	import com.google.gerrit.reviewdb.PatchSetInfo;
	import com.google.gerrit.reviewdb.ReviewDb;
	import com.google.gerrit.reviewdb.StarredChange;
	import com.google.gerrit.reviewdb.UserIdentity;
	import com.google.gerrit.server.IdentifiedUser;
	import com.google.gerrit.server.account.AccountCache;
	import com.google.gerrit.server.config.CanonicalWebUrl;
	import com.google.gerrit.server.git.GitRepositoryManager;
	import com.google.gerrit.server.patch.PatchList;
	import com.google.gerrit.server.patch.PatchListCache;
	import com.google.gerrit.server.patch.PatchListEntry;
	import com.google.gerrit.server.patch.PatchSetInfoFactory;
	import com.google.gerrit.server.patch.PatchSetInfoNotAvailableException;
	import com.google.gerrit.server.project.ProjectCache;
	import com.google.gerrit.server.project.ProjectState;
	import com.google.gwtorm.client.OrmException;
	import com.google.inject.Inject;
	import com.google.inject.Provider;

	import org.eclipse.jgit.util.SystemReader;

	import java.net.MalformedURLException;
	import java.net.URL;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.Date;
	import java.util.HashSet;
	import java.util.LinkedHashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Random;
	import java.util.Set;

	import javax.annotation.Nullable;

	/** Sends an email to one or more interested parties. */
	public abstract class OutgoingEmail {
	private static final String HDR_TO = "To";
	private static final String HDR_CC = "CC";

	private static final Random RNG = new Random();
	private final String messageClass;
	protected final Change change;
	protected String projectName;
	private final HashSet<Account.Id> rcptTo = new HashSet<Account.Id>();
	private final Map<String, EmailHeader> headers;
	private final List<Address> smtpRcptTo = new ArrayList<Address>();
	private Address smtpFromAddress;
	private StringBuilder body;
	private boolean inFooter;

	protected Account.Id fromId;
	protected PatchSet patchSet;
	protected PatchSetInfo patchSetInfo;
	protected ChangeMessage changeMessage;
	protected ReviewDb db;

	@Inject
	protected GitRepositoryManager server;

	@Inject
	private ProjectCache projectCache;

	@Inject
	private AccountCache accountCache;

	@Inject
	private PatchListCache patchListCache;

	@Inject
	private FromAddressGenerator fromAddressGenerator;

	@Inject
	private EmailSender emailSender;

	@Inject
	private PatchSetInfoFactory patchSetInfoFactory;

	@Inject
	private IdentifiedUser.GenericFactory identifiedUserFactory;

	@Inject
	@CanonicalWebUrl
	@Nullable
	private Provider<String> urlProvider;

	private ProjectState projectState;

	protected OutgoingEmail(final Change c, final String mc) {
	change = c;
	messageClass = mc;
	headers = new LinkedHashMap<String, EmailHeader>();
	}

	protected OutgoingEmail(final String mc) {
	this(null, mc);
	}

	public void setFrom(final Account.Id id) {
	fromId = id;
	}

	public void setPatchSet(final PatchSet ps) {
	patchSet = ps;
	}

	public void setPatchSet(final PatchSet ps, final PatchSetInfo psi) {
	patchSet = ps;
	patchSetInfo = psi;
	}

	public void setChangeMessage(final ChangeMessage cm) {
	changeMessage = cm;
	}

	public void setReviewDb(final ReviewDb d) {
	db = d;
	}

	/**
	* Format and enqueue the message for delivery.
	*
	* @throws EmailException
	*/
	public void send() throws EmailException {
	if (!emailSender.isEnabled()) {
	// Server has explicitly disabled email sending.
	//
	return;
	}

	init();
	format();
	if (shouldSendMessage()) {
	if (fromId != null) {
	// If we are impersonating a user, make sure they receive a CC of
	// this message so they can always review and audit what we sent
	// on their behalf to others.
	//
	add(RecipientType.CC, fromId);
	}
	if (change != null) {
	if (getChangeUrl() != null) {
	openFooter();
	appendText("To view visit ");
	appendText(getChangeUrl());
	appendText("\n");
	}
	if (getSettingsUrl() != null) {
	openFooter();
	appendText("To unsubscribe, visit ");
	appendText(getSettingsUrl());
	appendText("\n");
	}

	if (inFooter) {
	appendText("\n");
	} else {
	openFooter();
	}
	appendText("Gerrit-MessageType: " + messageClass + "\n");
	appendText("Gerrit-Project: " + projectName + "\n");
	appendText("Gerrit-Branch: " + change.getDest().getShortName() + "\n");
	}

	if (headers.get("Message-ID").isEmpty()) {
	final StringBuilder rndid = new StringBuilder();
	rndid.append("<");
	rndid.append(System.currentTimeMillis());
	rndid.append("-");
	rndid.append(Integer.toString(RNG.nextInt(999999), 36));
	rndid.append("@");
	rndid.append(SystemReader.getInstance().getHostname());
	rndid.append(">");
	setHeader("Message-ID", rndid.toString());
	}

	emailSender.send(smtpFromAddress, smtpRcptTo, headers, body.toString());
	}
	}

	/** Format the message body by calling {@link #appendText(String)}. */
	protected abstract void format();

	/** Setup the message headers and envelope (TO, CC, BCC). */
	protected void init() {
	if (change != null && projectCache != null) {
	projectState = projectCache.get(change.getProject());
	projectName =
	projectState != null ? projectState.getProject().getName() : null;
	} else {
	projectState = null;
	projectName = null;
	}

	smtpFromAddress = fromAddressGenerator.from(fromId);
	if (changeMessage != null && changeMessage.getWrittenOn() != null) {
	setHeader("Date", new Date(changeMessage.getWrittenOn().getTime()));
	} else {
	setHeader("Date", new Date());
	}
	headers.put("From", new EmailHeader.AddressList(smtpFromAddress));
	headers.put(HDR_TO, new EmailHeader.AddressList());
	headers.put(HDR_CC, new EmailHeader.AddressList());
	if (change != null) {
	setChangeSubjectHeader();
	}
	setHeader("Message-ID", "");

	if (fromId != null) {
	// If we have a user that this message is supposedly caused by
	// but the From header on the email does not match the user as
	// it is a generic header for this Gerrit server, include the
	// Reply-To header with the current user's email address.
	//
	final Address a = toAddress(fromId);
	if (a != null && !smtpFromAddress.email.equals(a.email)) {
	setHeader("Reply-To", a.email);
	}
	}

	setHeader("X-Gerrit-MessageType", messageClass);
	if (change != null) {
	setHeader("X-Gerrit-Change-Id", "" + change.getKey().get());
	setListIdHeader();
	setChangeUrlHeader();
	setCommitIdHeader();
	}
	body = new StringBuilder();
	inFooter = false;

	if (fromId != null && fromAddressGenerator.isGenericAddress(fromId)) {
	final Account account = accountCache.get(fromId).getAccount();
	final String name = account.getFullName();
	final String email = account.getPreferredEmail();

	if ((name != null && !name.isEmpty())
	\|\| (email != null && !email.isEmpty())) {
	body.append("From");
	if (name != null && !name.isEmpty()) {
	body.append(" ").append(name);
	}
	if (email != null && !email.isEmpty()) {
	body.append(" <").append(email).append(">");
	}
	body.append(":\n\n");
	}
	}

	if (change != null && db != null) {
	if (patchSet == null) {
	try {
	patchSet = db.patchSets().get(change.currentPatchSetId());
	} catch (OrmException err) {
	patchSet = null;
	}
	}

	if (patchSet != null && patchSetInfo == null) {
	try {
	patchSetInfo = patchSetInfoFactory.get(patchSet.getId());
	} catch (PatchSetInfoNotAvailableException err) {
	patchSetInfo = null;
	}
	}
	}
	}

	private void setListIdHeader() {
	// Set a reasonable list id so that filters can be used to sort messages
	//
	final StringBuilder listid = new StringBuilder();
	listid.append("gerrit-");
	listid.append(projectName.replace('/', '-'));
	listid.append("@");
	listid.append(getGerritHost());

	final String listidStr = listid.toString();
	setHeader("Mailing-List", "list " + listidStr);
	setHeader("List-Id", "<" + listidStr.replace('@', '.') + ">");
	if (getSettingsUrl() != null) {
	setHeader("List-Unsubscribe", "<" + getSettingsUrl() + ">");
	}
	}

	private void setChangeUrlHeader() {
	final String u = getChangeUrl();
	if (u != null) {
	setHeader("X-Gerrit-ChangeURL", "<" + u + ">");
	}
	}

	private void setCommitIdHeader() {
	if (patchSet != null && patchSet.getRevision() != null
	&& patchSet.getRevision().get() != null
	&& patchSet.getRevision().get().length() > 0) {
	setHeader("X-Gerrit-Commit", patchSet.getRevision().get());
	}
	}

	private void setChangeSubjectHeader() {
	final StringBuilder subj = new StringBuilder();
	subj.append("[");
	subj.append(change.getDest().getShortName());
	subj.append("] ");
	subj.append("Change ");
	subj.append(change.getKey().abbreviate());
	subj.append(": (");
	subj.append(projectName);
	subj.append(") ");
	if (change.getSubject().length() > 60) {
	subj.append(change.getSubject().substring(0, 60));
	subj.append("...");
	} else {
	subj.append(change.getSubject());
	}
	setHeader("Subject", subj.toString());
	}

	protected String getGerritHost() {
	if (getGerritUrl() != null) {
	try {
	return new URL(getGerritUrl()).getHost();
	} catch (MalformedURLException e) {
	// Try something else.
	}
	}

	// Fall back onto whatever the local operating system thinks
	// this server is called. We hopefully didn't get here as a
	// good admin would have configured the canonical url.
	//
	return SystemReader.getInstance().getHostname();
	}

	/** Get a link to the change; null if the server doesn't know its own address. */
	protected String getChangeUrl() {
	if (change != null && getGerritUrl() != null) {
	final StringBuilder r = new StringBuilder();
	r.append(getGerritUrl());
	r.append(change.getChangeId());
	return r.toString();
	}
	return null;
	}

	private String getSettingsUrl() {
	if (getGerritUrl() != null) {
	final StringBuilder r = new StringBuilder();
	r.append(getGerritUrl());
	r.append("settings");
	return r.toString();
	}
	return null;
	}

	protected String getGerritUrl() {
	return urlProvider.get();
	}

	protected String getChangeMessageThreadId() {
	final StringBuilder r = new StringBuilder();
	r.append('<');
	r.append("gerrit");
	r.append('.');
	r.append(change.getCreatedOn().getTime());
	r.append('.');
	r.append(change.getKey().get());
	r.append('@');
	r.append(getGerritHost());
	r.append('>');
	return r.toString();
	}

	/** Set a header in the outgoing message. */
	protected void setHeader(final String name, final String value) {
	headers.put(name, new EmailHeader.String(value));
	}

	protected void setHeader(final String name, final Date date) {
	headers.put(name, new EmailHeader.Date(date));
	}

	/** Append text to the outgoing email body. */
	protected void appendText(final String text) {
	if (text != null) {
	body.append(text);
	}
	}

	private void openFooter() {
	if (!inFooter) {
	inFooter = true;
	appendText("-- \n");
	}
	}

	/** Format the sender's "cover letter", {@link #getCoverLetter()}. */
	protected void formatCoverLetter() {
	final String cover = getCoverLetter();
	if (!"".equals(cover)) {
	appendText(cover);
	appendText("\n\n");
	}
	}

	/** Get the text of the "cover letter", from {@link ChangeMessage}. */
	protected String getCoverLetter() {
	if (changeMessage != null) {
	final String txt = changeMessage.getMessage();
	if (txt != null) {
	return txt.trim();
	}
	}
	return "";
	}

	/** Format the change message and the affected file list. */
	protected void formatChangeDetail() {
	if (patchSetInfo != null) {
	appendText(patchSetInfo.getMessage().trim());
	appendText("\n");
	} else {
	appendText(change.getSubject().trim());
	appendText("\n");
	}

	if (patchSet != null) {
	appendText("---\n");
	for (PatchListEntry p : getPatchList().getPatches()) {
	appendText(p.getChangeType().getCode() + " " + p.getNewName() + "\n");
	}
	appendText("\n");
	}
	}

	/** Get the patch list corresponding to this patch set. */
	protected PatchList getPatchList() {
	if (patchSet != null) {
	return patchListCache.get(change, patchSet);
	}
	return null;
	}

	/** Lookup a human readable name for an account, usually the "full name". */
	protected String getNameFor(final Account.Id accountId) {
	if (accountId == null) {
	return "Anonymous Coward";
	}

	final Account userAccount = accountCache.get(accountId).getAccount();
	String name = userAccount.getFullName();
	if (name == null) {
	name = userAccount.getPreferredEmail();
	}
	if (name == null) {
	name = "Anonymous Coward #" + accountId;
	}
	return name;
	}

	protected boolean shouldSendMessage() {
	if (body.length() == 0) {
	// If we have no message body, don't send.
	//
	return false;
	}

	if (rcptTo.isEmpty()) {
	// If we have nobody to send this message to, then all of our
	// selection filters previously for this type of message were
	// unable to match a destination. Don't bother sending it.
	//
	return false;
	}

	if (rcptTo.size() == 1 && rcptTo.contains(fromId)) {
	// If the only recipient is also the sender, don't bother.
	//
	return false;
	}

	return true;
	}

	/** Get the project entity the change is in; null if its been deleted. */
	protected ProjectState getProjectState() {
	return projectState;
	}

	/** Get the groups which own the project. */
	protected Set<AccountGroup.Id> getProjectOwners() {
	final ProjectState r;

	r = projectCache.get(change.getProject());
	return r != null ? r.getOwners() : Collections.<AccountGroup.Id> emptySet();
	}

	/** Schedule this message for delivery to the listed accounts. */
	protected void add(final RecipientType rt, final Collection<Account.Id> list) {
	for (final Account.Id id : list) {
	add(rt, id);
	}
	}

	/** TO or CC all vested parties (change owner, patch set uploader, author). */
	protected void rcptToAuthors(final RecipientType rt) {
	add(rt, change.getOwner());
	if (patchSet != null) {
	add(rt, patchSet.getUploader());
	}
	if (patchSetInfo != null) {
	add(rt, patchSetInfo.getAuthor());
	add(rt, patchSetInfo.getCommitter());
	}
	}

	private void add(final RecipientType rt, final UserIdentity who) {
	if (who != null && who.getAccount() != null) {
	add(rt, who.getAccount());
	}
	}

	/** BCC any user who has starred this change. */
	protected void bccStarredBy() {
	if (db != null) {
	try {
	// BCC anyone who has starred this change.
	//
	for (StarredChange w : db.starredChanges().byChange(change.getId())) {
	add(RecipientType.BCC, w.getAccountId());
	}
	} catch (OrmException err) {
	// Just don't BCC everyone. Better to send a partial message to those
	// we already have queued up then to fail deliver entirely to people
	// who have a lower interest in the change.
	}
	}
	}

	/** BCC any user who has set "notify all comments" on this project. */
	protected void bccWatchesNotifyAllComments() {
	if (db != null) {
	try {
	// BCC anyone else who has interest in this project's changes
	//
	final ProjectState ps = getProjectState();
	if (ps != null) {
	for (final AccountProjectWatch w : db.accountProjectWatches()
	.notifyAllComments(ps.getProject().getNameKey())) {
	add(RecipientType.BCC, w.getAccountId());
	}
	}
	} catch (OrmException err) {
	// Just don't CC everyone. Better to send a partial message to those
	// we already have queued up then to fail deliver entirely to people
	// who have a lower interest in the change.
	}
	}
	}

	/** Any user who has published comments on this change. */
	protected void ccAllApprovals() {
	ccApprovals(true);
	}

	/** Users who have non-zero approval codes on the change. */
	protected void ccExistingReviewers() {
	ccApprovals(false);
	}

	private void ccApprovals(final boolean includeZero) {
	if (db != null) {
	try {
	// CC anyone else who has posted an approval mark on this change
	//
	for (PatchSetApproval ap : db.patchSetApprovals().byChange(
	change.getId())) {
	if (!includeZero && ap.getValue() == 0) {
	continue;
	}
	add(RecipientType.CC, ap.getAccountId());
	}
	} catch (OrmException err) {
	}
	}
	}

	/** Schedule delivery of this message to the given account. */
	protected void add(final RecipientType rt, final Account.Id to) {
	if (!rcptTo.contains(to) && isVisibleTo(to)) {
	rcptTo.add(to);
	add(rt, toAddress(to));
	}
	}

	private boolean isVisibleTo(final Account.Id to) {
	return projectState == null
	\|\| change == null
	\|\| projectState.controlFor(identifiedUserFactory.create(to))
	.controlFor(change).isVisible();
	}

	/** Schedule delivery of this message to the given account. */
	protected void add(final RecipientType rt, final Address addr) {
	if (addr != null && addr.email != null && addr.email.length() > 0) {
	smtpRcptTo.add(addr);
	switch (rt) {
	case TO:
	((EmailHeader.AddressList) headers.get(HDR_TO)).add(addr);
	break;
	case CC:
	((EmailHeader.AddressList) headers.get(HDR_CC)).add(addr);
	break;
	}
	}
	}

	private Address toAddress(final Account.Id id) {
	final Account a = accountCache.get(id).getAccount();
	final String e = a.getPreferredEmail();
	if (e == null) {
	return null;
	}
	return new Address(a.getFullName(), e);
	}
	}