org.obm.push.mail.BodyPreferencePolicy.java Source code

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Here is the source code for org.obm.push.mail.BodyPreferencePolicy.java

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/* ***** BEGIN LICENSE BLOCK *****
 * 
 * Copyright (C) 2011-2014  Linagora
 *
 * This program is free software: you can redistribute it and/or 
 * modify it under the terms of the GNU Affero General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version, provided you comply 
 * with the Additional Terms applicable for OBM connector by Linagora 
 * pursuant to Section 7 of the GNU Affero General Public License, 
 * subsections (b), (c), and (e), pursuant to which you must notably (i) retain 
 * the Message sent thanks to OBM, Free Communication by Linagora? 
 * signature notice appended to any and all outbound messages 
 * (notably e-mail and meeting requests), (ii) retain all hypertext links between 
 * OBM and obm.org, as well as between Linagora and linagora.com, and (iii) refrain 
 * from infringing Linagora intellectual property rights over its trademarks 
 * and commercial brands. Other Additional Terms apply, 
 * see <http://www.linagora.com/licenses/> for more details. 
 *
 * This program is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License 
 * for more details. 
 *
 * You should have received a copy of the GNU Affero General Public License 
 * and its applicable Additional Terms for OBM along with this program. If not, 
 * see <http://www.gnu.org/licenses/> for the GNU Affero General Public License version 3 
 * and <http://www.linagora.com/licenses/> for the Additional Terms applicable to 
 * OBM connectors. 
 * 
 * ***** END LICENSE BLOCK ***** */
package org.obm.push.mail;

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

import org.obm.push.bean.BodyPreference;
import org.obm.push.bean.MSEmailBodyType;
import org.obm.push.mail.mime.ContentType;

import com.google.common.base.Function;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Ordering;

public abstract class BodyPreferencePolicy {

    protected static final int DEFAULT_TRUNCATION_SIZE = 32 * 1024;
    protected static final ImmutableList<BodyPreference> DEFAULT_BODY_PREFERENCES = ImmutableList
            .<BodyPreference>builder()
            .add(BodyPreference.builder().bodyType(MSEmailBodyType.PlainText)
                    .truncationSize(DEFAULT_TRUNCATION_SIZE).build())
            .add(BodyPreference.builder().bodyType(MSEmailBodyType.HTML).truncationSize(DEFAULT_TRUNCATION_SIZE)
                    .build())
            .build();

    public abstract List<BodyPreference> bodyPreferencesMatchingPolicy(List<BodyPreference> bodyPreferences);

    public abstract boolean mayUsesDefaultBodyPreferences();

    public FetchInstruction selectBetterFit(List<FetchInstruction> fetchInstructions,
            List<BodyPreference> bodyPreferences) {
        if (fetchInstructions.isEmpty()) {
            return null;
        }
        return Ordering.from(betterFitComparator(bodyPreferences)).min(fetchInstructions);
    }

    public List<FetchHints> listContentTypes(MSEmailBodyType bodyType) {
        switch (bodyType) {
        case HTML:
            return Arrays.asList(FetchHints.builder().contentType(toContentType(MSEmailBodyType.HTML)).build());
        case PlainText:
            return Arrays
                    .asList(FetchHints.builder().contentType(toContentType(MSEmailBodyType.PlainText)).build());
        case RTF:
            return Arrays.asList(FetchHints.builder().contentType(toContentType(MSEmailBodyType.RTF)).build());
        default:
            throw new IllegalArgumentException("Unexpected MSEmailBodyType");
        }
    }

    protected static Comparator<FetchInstruction> betterFitComparator(final List<BodyPreference> bodyPreferences) {
        final List<MSEmailBodyType> preferences = FluentIterable
                .from(Iterables.concat(bodyPreferences, DEFAULT_BODY_PREFERENCES))
                .transform(bodyPreferenceToMSEmailBodyType()).toList();
        final List<MSEmailBodyType> clientPreferences = FluentIterable.from(bodyPreferences)
                .transform(bodyPreferenceToMSEmailBodyType()).toList();

        return new Comparator<FetchInstruction>() {

            private int computeWeight(FetchInstruction instruction) {
                int transformationWeight = instruction.getMailTransformation() == MailTransformation.NONE ? 0 : 1;
                return preferences.indexOf(instruction.getBodyType()) + (preferences.size() * transformationWeight);
            }

            @Override
            public int compare(FetchInstruction o1, FetchInstruction o2) {
                if (o1.getBodyType().equals(o2.getBodyType())
                        && o1.getMailTransformation().equals(o2.getMailTransformation())) {
                    return 0;
                }
                if (o1.getBodyType() == MSEmailBodyType.MIME) {
                    return 1;
                } else if (o2.getBodyType() == MSEmailBodyType.MIME) {
                    return -1;
                } else if (clientPreferences.contains(o1.getBodyType())
                        && !clientPreferences.contains(o2.getBodyType())) {
                    return -1;
                } else if (!clientPreferences.contains(o1.getBodyType())
                        && clientPreferences.contains(o2.getBodyType())) {
                    return 1;
                } else {
                    return computeWeight(o1) - computeWeight(o2);
                }
            }
        };
    }

    private static Function<BodyPreference, MSEmailBodyType> bodyPreferenceToMSEmailBodyType() {
        return new Function<BodyPreference, MSEmailBodyType>() {
            @Override
            public MSEmailBodyType apply(BodyPreference input) {
                return input.getType();
            }
        };
    }

    protected ContentType toContentType(MSEmailBodyType bodyType) {
        String contentType = toMimeType(bodyType);
        return ContentType.builder().contentType(contentType).build();
    }

    private String toMimeType(MSEmailBodyType bodyType) {
        switch (bodyType) {
        case PlainText:
            return "text/plain";
        case HTML:
            return "text/html";
        case RTF:
            return "text/rtf";
        default:
            throw new IllegalArgumentException("Unexpected MSEmailBodyType");
        }
    }
}