Java tutorial
/** * Copyright (C) cedarsoft GmbH. * * Licensed under the GNU General Public License version 3 (the "License") * with Classpath Exception; you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.cedarsoft.org/gpl3ce * (GPL 3 with Classpath Exception) * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 3 only, as * published by the Free Software Foundation. cedarsoft GmbH designates this * particular file as subject to the "Classpath" exception as provided * by cedarsoft GmbH in the LICENSE file that accompanied this code. * * This code 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 * version 3 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 3 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact cedarsoft GmbH, 72810 Gomaringen, Germany, * or visit www.cedarsoft.com if you need additional information or * have any questions. */ package com.cedarsoft.couchdb.io; import com.cedarsoft.couchdb.core.DocId; import com.cedarsoft.couchdb.core.Revision; import com.cedarsoft.couchdb.core.UniqueId; import com.cedarsoft.serialization.jackson.AbstractJacksonSerializer; import com.cedarsoft.serialization.jackson.filter.Filter; import com.cedarsoft.serialization.jackson.filter.FilteringJsonParser; import com.cedarsoft.version.Version; import com.cedarsoft.version.VersionException; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.core.JsonParseException; import com.fasterxml.jackson.core.JsonParser; import javax.annotation.Nonnull; import javax.annotation.Nullable; import javax.annotation.WillNotClose; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; /** * This wrapper skips couchdb specific entries ("_id" and "_rev"). * <p/> * Wraps a default serializer. * <p/> * ATTENTION: Serializing is only supported for test cases and requires additional informations. Use * {@link #serialize(Object, OutputStream, DocId, Revision)} for those cases! * * @param <T> the type * @author Johannes Schneider (<a href="mailto:js@cedarsoft.com">js@cedarsoft.com</a>) */ public class CouchSerializerWrapper<T> extends AbstractJacksonSerializer<T> { public static final String ID = "_id"; public static final String REV = "_rev"; @Nonnull private final AbstractJacksonSerializer<T> delegate; public CouchSerializerWrapper(@Nonnull AbstractJacksonSerializer<T> delegate) { super(delegate.getType(), delegate.getFormatVersionRange()); if (!delegate.isObjectType()) { throw new IllegalStateException( "Not supported for object type serializer: " + delegate.getClass().getName()); } this.delegate = delegate; } /** * Serialization is only supported for test cases. This method just delegates everything * * @param serializeTo serialize to * @param object the object * @param formatVersion the format version * @throws IOException * @throws VersionException */ @Override public void serialize(@Nonnull JsonGenerator serializeTo, @Nonnull T object, @Nonnull Version formatVersion) throws IOException, VersionException { delegate.serialize(serializeTo, object, formatVersion); } @Override protected void beforeTypeAndVersion(@Nonnull T object, @Nonnull JsonGenerator serializeTo) throws IOException { UniqueId uniqueId = getUniqueId(); serializeTo.writeStringField(ID, uniqueId.getId().asString()); serializeTo.writeStringField(REV, uniqueId.getRevision().asString()); super.beforeTypeAndVersion(object, serializeTo); } /** * @noinspection RefusedBequest */ @Deprecated @Override public void serialize(@Nonnull T object, @WillNotClose @Nonnull OutputStream out) throws IOException { throw new UnsupportedOperationException("Use #serialize(Object, OutputStream, DocId, Revision) instead"); } /** * @param object the object to serialize * @param out the output stream * @param id the document id * @param revision the revision */ @Deprecated public void serialize(@Nonnull T object, @WillNotClose @Nonnull OutputStream out, @Nonnull DocId id, @Nonnull Revision revision) throws IOException { storeUniqueId(new UniqueId(id, revision)); super.serialize(object, out); } /** * Only necessary for serialization in tests! */ @Nonnull @Deprecated private static final ThreadLocal<UniqueId> uniqueIdThreadLocal = new ThreadLocal<>(); @Deprecated private static void storeUniqueId(@Nonnull UniqueId uniqueId) { uniqueIdThreadLocal.set(uniqueId); } @Deprecated @Nonnull private static UniqueId getUniqueId() { @Nullable UniqueId resolved = uniqueIdThreadLocal.get(); if (resolved == null) { throw new IllegalStateException("No unique id found"); } uniqueIdThreadLocal.remove(); return resolved; } @Nonnull @Override protected JsonParser createJsonParser(@Nonnull JsonFactory jsonFactory, @Nonnull InputStream in) throws IOException { JsonParser parser = super.createJsonParser(jsonFactory, in); return new FilteringJsonParser(parser, new Filter() { @Override public boolean shallFilterOut(@Nonnull JsonParser parser) throws IOException, JsonParseException { @Nullable String currentName = parser.getCurrentName(); return currentName.startsWith("_"); } }); } @Nonnull @Override public T deserialize(@Nonnull JsonParser deserializeFrom, @Nonnull Version formatVersion) throws IOException, VersionException { return delegate.deserialize(deserializeFrom, formatVersion); } }