Java tutorial
/* * Syncany, www.syncany.org * Copyright (C) 2011-2015 Philipp C. Heckel <philipp.heckel@gmail.com> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package org.syncany.plugins.transfer; import java.lang.reflect.Field; import java.util.List; import org.simpleframework.xml.Element; import org.syncany.util.ReflectionUtil; import com.google.common.collect.ImmutableList; import com.google.common.collect.Lists; import com.google.common.collect.Ordering; import com.google.common.primitives.Ints; /** * Helper class to read the options of a {@link TransferSettings} using the * {@link Setup} and {@link Element} annotations. * * @author Christian Roth <christian.roth@port17.de> */ public class TransferPluginOptions { private static final int MAX_NESTED_LEVELS = 3; /** * Get an ordered list of {@link TransferPluginOption}s, given class a {@link TransferSettings} class. * * <p>This method uses the {@link Setup} and {@link Element} annotation, and their attributes * to sort the options. If no annotation is given or no order attribute is provided, the * option will be listed last. */ public static List<TransferPluginOption> getOrderedOptions( Class<? extends TransferSettings> transferSettingsClass) { return getOrderedOptions(transferSettingsClass, 0); } private static List<TransferPluginOption> getOrderedOptions( Class<? extends TransferSettings> transferSettingsClass, int level) { List<Field> fields = getOrderedFields(transferSettingsClass); ImmutableList.Builder<TransferPluginOption> options = ImmutableList.builder(); for (Field field : fields) { TransferPluginOption option = getOptionFromField(field, transferSettingsClass, level); options.add(option); } return options.build(); } private static TransferPluginOption getOptionFromField(Field field, Class<? extends TransferSettings> transferSettingsClass, int level) { Element elementAnnotation = field.getAnnotation(Element.class); Setup setupAnnotation = field.getAnnotation(Setup.class); boolean hasName = !elementAnnotation.name().equalsIgnoreCase(""); boolean hasDescription = setupAnnotation != null && !setupAnnotation.description().equals(""); boolean hasCallback = setupAnnotation != null && !setupAnnotation.callback().isInterface(); boolean hasConverter = setupAnnotation != null && !setupAnnotation.converter().isInterface(); boolean hasFileType = setupAnnotation != null && setupAnnotation.fileType() != null; String name = (hasName) ? elementAnnotation.name() : field.getName(); String description = (hasDescription) ? setupAnnotation.description() : field.getName(); FileType fileType = (hasFileType) ? setupAnnotation.fileType() : null; boolean required = elementAnnotation.required(); boolean sensitive = setupAnnotation != null && setupAnnotation.sensitive(); boolean singular = setupAnnotation != null && setupAnnotation.singular(); boolean visible = setupAnnotation != null && setupAnnotation.visible(); boolean encrypted = field.getAnnotation(Encrypted.class) != null; Class<? extends TransferPluginOptionCallback> callback = (hasCallback) ? setupAnnotation.callback() : null; Class<? extends TransferPluginOptionConverter> converter = (hasConverter) ? setupAnnotation.converter() : null; boolean isNestedOption = TransferSettings.class.isAssignableFrom(field.getType()); if (isNestedOption) { return createNestedOption(field, level, name, description, fileType, encrypted, sensitive, singular, visible, required, callback, converter); } else { return createNormalOption(field, transferSettingsClass, name, description, fileType, encrypted, sensitive, singular, visible, required, callback, converter); } } @SuppressWarnings("unchecked") private static TransferPluginOption createNestedOption(Field field, int level, String name, String description, FileType fileType, boolean encrypted, boolean sensitive, boolean singular, boolean visible, boolean required, Class<? extends TransferPluginOptionCallback> callback, Class<? extends TransferPluginOptionConverter> converter) { if (++level > MAX_NESTED_LEVELS) { throw new RuntimeException( "Plugin uses too many nested transfer settings (max allowed value: " + MAX_NESTED_LEVELS + ")"); } Class<? extends TransferSettings> fieldClass = (Class<? extends TransferSettings>) field.getType(); return new NestedTransferPluginOption(field, name, description, fieldClass, fileType, encrypted, sensitive, singular, visible, required, callback, converter, getOrderedOptions(fieldClass)); } private static TransferPluginOption createNormalOption(Field field, Class<? extends TransferSettings> transferSettingsClass, String name, String description, FileType fileType, boolean encrypted, boolean sensitive, boolean singular, boolean visible, boolean required, Class<? extends TransferPluginOptionCallback> callback, Class<? extends TransferPluginOptionConverter> converter) { return new TransferPluginOption(field, name, description, field.getType(), fileType, encrypted, sensitive, singular, visible, required, callback, converter); } private static List<Field> getOrderedFields(Class<? extends TransferSettings> transferSettingsClass) { Ordering<Field> byOrderAnnotation = new Ordering<Field>() { @Override public int compare(Field leftField, Field rightField) { int leftOrderValue = (leftField.getAnnotation(Setup.class) != null) ? leftField.getAnnotation(Setup.class).order() : -1; int rightOrderValue = (rightField.getAnnotation(Setup.class) != null) ? rightField.getAnnotation(Setup.class).order() : -1; return Ints.compare(leftOrderValue, rightOrderValue); } }; List<Field> fields = Lists .newArrayList(ReflectionUtil.getAllFieldsWithAnnotation(transferSettingsClass, Element.class)); return ImmutableList.copyOf(byOrderAnnotation.nullsLast().sortedCopy(fields)); } }