Java tutorial
/* * Apache License * Version 2.0, January 2004 * http://www.apache.org/licenses/ * * TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION * * 1. Definitions. * * "License" shall mean the terms and conditions for use, reproduction, and * distribution as defined by Sections 1 through 9 of this document. * * "Licensor" shall mean the copyright owner or entity authorized by the copyright * owner that is granting the License. * * "Legal Entity" shall mean the union of the acting entity and all other entities * that control, are controlled by, or are under common control with that entity. * For the purposes of this definition, "control" means (i) the power, direct or * indirect, to cause the direction or management of such entity, whether by * contract or otherwise, or (ii) ownership of fifty percent (50%) or more of the * outstanding shares, or (iii) beneficial ownership of such entity. * * "You" (or "Your") shall mean an individual or Legal Entity exercising * permissions granted by this License. * * "Source" form shall mean the preferred form for making modifications, including * but not limited to software tagSource code, documentation tagSource, and configuration * files. * * "Object" form shall mean any form resulting from mechanical transformation or * translation of a Source form, including but not limited to compiled object code, * generated documentation, and conversions to other media types. * * "Work" shall mean the work of authorship, whether in Source or Object form, made * available under the License, as indicated by a copyright notice that is included * in or attached to the work (an example is provided in the Appendix below). * * "Derivative Works" shall mean any work, whether in Source or Object form, that * is based on (or derived from) the Work and for which the editorial revisions, * annotations, elaborations, or other modifications represent, as a whole, an * original work of authorship. For the purposes of this License, Derivative Works * shall not include works that remain separable from, or merely link (or bind by * name) to the interfaces of, the Work and Derivative Works thereof. * * "Contribution" shall mean any work of authorship, including the original version * of the Work and any modifications or additions to that Work or Derivative Works * thereof, that is intentionally submitted to Licensor for inclusion in the Work * by the copyright owner or by an individual or Legal Entity authorized to submit * on behalf of the copyright owner. For the purposes of this definition, * "submitted" means any form of electronic, verbal, or written communication sent * to the Licensor or its representatives, including but not limited to * communication on electronic mailing lists, tagSource code control systems, and * issue tracking systems that are managed by, or on behalf of, the Licensor for * the purpose of discussing and improving the Work, but excluding communication * that is conspicuously marked or otherwise designated in writing by the copyright * owner as "Not a Contribution." * * "Contributor" shall mean Licensor and any individual or Legal Entity on behalf * of whom a Contribution has been received by Licensor and subsequently * incorporated within the Work. * * 2. Grant of Copyright License. * * Subject to the terms and conditions of this License, each Contributor hereby * grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, * irrevocable copyright license to reproduce, prepare Derivative Works of, * publicly display, publicly perform, sublicense, and distribute the Work and such * Derivative Works in Source or Object form. * * 3. Grant of Patent License. * * Subject to the terms and conditions of this License, each Contributor hereby * grants to You a perpetual, worldwide, non-exclusive, no-charge, royalty-free, * irrevocable (except as stated in this section) patent license to make, have * made, use, offer to sell, sell, import, and otherwise transfer the Work, where * such license applies only to those patent claims licensable by such Contributor * that are necessarily infringed by their Contribution(s) alone or by combination * of their Contribution(s) with the Work to which such Contribution(s) was * submitted. If You institute patent litigation against any entity (including a * cross-claim or counterclaim in a lawsuit) alleging that the Work or a * Contribution incorporated within the Work constitutes direct or contributory * patent infringement, then any patent licenses granted to You under this License * for that Work shall terminate as of the date such litigation is filed. * * 4. Redistribution. * * You may reproduce and distribute copies of the Work or Derivative Works thereof * in any medium, with or without modifications, and in Source or Object form, * provided that You meet the following conditions: * * You must give any other recipients of the Work or Derivative Works a copy of * this License; and * You must cause any modified files to carry prominent notices stating that You * changed the files; and * You must retain, in the Source form of any Derivative Works that You distribute, * all copyright, patent, trademark, and attribution notices from the Source form * of the Work, excluding those notices that do not pertain to any part of the * Derivative Works; and * If the Work includes a "NOTICE" text file as part of its distribution, then any * Derivative Works that You distribute must include a readable copy of the * attribution notices contained within such NOTICE file, excluding those notices * that do not pertain to any part of the Derivative Works, in at least one of the * following places: within a NOTICE text file distributed as part of the * Derivative Works; within the Source form or documentation, if provided along * with the Derivative Works; or, within a display generated by the Derivative * Works, if and wherever such third-party notices normally appear. The contents of * the NOTICE file are for informational purposes only and do not modify the * License. You may add Your own attribution notices within Derivative Works that * You distribute, alongside or as an addendum to the NOTICE text from the Work, * provided that such additional attribution notices cannot be construed as * modifying the License. * You may add Your own copyright statement to Your modifications and may provide * additional or different license terms and conditions for use, reproduction, or * distribution of Your modifications, or for any such Derivative Works as a whole, * provided Your use, reproduction, and distribution of the Work otherwise complies * with the conditions stated in this License. * * 5. Submission of Contributions. * * Unless You explicitly state otherwise, any Contribution intentionally submitted * for inclusion in the Work by You to the Licensor shall be under the terms and * conditions of this License, without any additional terms or conditions. * Notwithstanding the above, nothing herein shall supersede or modify the terms of * any separate license agreement you may have executed with Licensor regarding * such Contributions. * * 6. Trademarks. * * This License does not grant permission to use the trade names, trademarks, * service marks, or product names of the Licensor, except as required for * reasonable and customary use in describing the origin of the Work and * reproducing the content of the NOTICE file. * * 7. Disclaimer of Warranty. * * Unless required by applicable law or agreed to in writing, Licensor provides the * Work (and each Contributor provides its Contributions) on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied, * including, without limitation, any warranties or conditions of TITLE, * NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. You are * solely responsible for determining the appropriateness of using or * redistributing the Work and assume any risks associated with Your exercise of * permissions under this License. * * 8. Limitation of Liability. * * In no event and under no legal theory, whether in tort (including negligence), * contract, or otherwise, unless required by applicable law (such as deliberate * and grossly negligent acts) or agreed to in writing, shall any Contributor be * liable to You for damages, including any direct, indirect, special, incidental, * or consequential damages of any character arising as a result of this License or * out of the use or inability to use the Work (including but not limited to * damages for loss of goodwill, work stoppage, computer failure or malfunction, or * any and all other commercial damages or losses), even if such Contributor has * been advised of the possibility of such damages. * * 9. Accepting Warranty or Additional Liability. * * While redistributing the Work or Derivative Works thereof, You may choose to * offer, and charge a fee for, acceptance of support, warranty, indemnity, or * other liability obligations and/or rights consistent with this License. However, * in accepting such obligations, You may act only on Your own behalf and on Your * sole responsibility, not on behalf of any other Contributor, and only if You * agree to indemnify, defend, and hold each Contributor harmless for any liability * incurred by, or claims asserted against, such Contributor by reason of your * accepting any such warranty or additional liability. * * END OF TERMS AND CONDITIONS * * APPENDIX: How to apply the Apache License to your work * * To apply the Apache License to your work, attach the following boilerplate * notice, with the fields enclosed by brackets "[]" replaced with your own * identifying information. (Don't include the brackets!) The text should be * enclosed in the appropriate comment syntax for the file format. We also * recommend that a file or class name and description of purpose be included on * the same "printed page" as the copyright notice for easier identification within * third-party archives. * * Copyright [yyyy] [name of copyright owner] * * 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 org.normandra.cassandra; import com.datastax.driver.core.*; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.NullArgumentException; import org.apache.commons.lang.StringUtils; import org.normandra.Database; import org.normandra.DatabaseConstruction; import org.normandra.NormandraException; import org.normandra.cache.EntityCacheFactory; import org.normandra.data.BasicColumnAccessorFactory; import org.normandra.meta.*; import org.normandra.util.ArraySet; import org.normandra.util.CaseUtils; import org.normandra.util.QueryUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.SequenceGenerator; import javax.persistence.TableGenerator; import java.lang.reflect.Field; import java.util.*; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.atomic.AtomicInteger; import java.util.regex.Matcher; import java.util.regex.Pattern; import java.util.regex.PatternSyntaxException; import java.util.stream.Collectors; /** * a cassandra database * <p> * Date: 8/31/13 */ public class CassandraDatabase implements Database, CassandraAccessor { private static final Logger logger = LoggerFactory.getLogger(CassandraDatabase.class); private static final AtomicInteger counter = new AtomicInteger(); private static final ExecutorService singleExecutor = Executors.newCachedThreadPool(r -> { final Thread thread = new Thread(r); thread.setDaemon(true); thread.setName("CassandraWorker-" + counter.incrementAndGet()); return thread; }); public static CassandraDatabase create(final String host, final String keyspaceName, final EntityCacheFactory cache, final DatabaseConstruction mode, final DatabaseMetaBuilder metaBuilder) { return create(host, -1, keyspaceName, cache, mode, metaBuilder); } public static CassandraDatabase create(final String host, final int port, final String keyspaceName, final EntityCacheFactory cache, final DatabaseConstruction mode, final DatabaseMetaBuilder metaBuilder) { final Cluster cluster = buildCluster(host, port); final DatabaseMeta meta = metaBuilder.create(); return new CassandraDatabase(keyspaceName, cluster, cache, mode, singleExecutor, meta); } private static Cluster buildCluster(final String host, final int port) { final Cluster.Builder builder = Cluster.builder().addContactPoint(host); // builder.withSSL(); if (port <= 0) { return builder.build(); } return builder.withPort(port).build(); } private final EntityCacheFactory cache; private final Cluster cluster; private final String keyspaceName; private final DatabaseConstruction constructionMode; private final Map<String, org.normandra.cassandra.CassandraPreparedStatement> statementsByName = new ConcurrentHashMap<>(); private final DatabaseMeta meta; private final ExecutorService executor; private Session session; public CassandraDatabase(final String keyspace, final Cluster cluster, final EntityCacheFactory cache, final DatabaseConstruction mode, final ExecutorService executor, final DatabaseMeta meta) { if (null == keyspace) { throw new NullArgumentException("keyspace"); } if (null == cluster) { throw new NullArgumentException("host"); } if (null == mode) { throw new NullArgumentException("mode"); } if (null == cache) { throw new NullArgumentException("cache factory"); } if (null == executor) { throw new NullArgumentException("executor"); } this.keyspaceName = keyspace; this.cluster = cluster; this.constructionMode = mode; this.cache = cache; this.executor = executor; this.meta = meta; } @Override public DatabaseMeta getMeta() { return this.meta; } @Override public CassandraDatabaseSession createSession() { return new CassandraDatabaseSession(this.keyspaceName, this.ensureSession(), this.statementsByName, this.cache.create(), this.executor); } @Override public boolean registerQuery(final EntityMeta entity, final String name, final String query) throws NormandraException { if (null == name || name.isEmpty()) { return false; } if (null == query || query.isEmpty()) { return false; } if (this.statementsByName.containsKey(name)) { return false; } final String tableQuery = QueryUtils.prepare(entity, query); if (null == tableQuery || tableQuery.isEmpty()) { return false; } try { final List<String> list = new ArrayList<>(); final StringBuilder buffer = new StringBuilder(); final Matcher matcher = Pattern.compile(":\\w+").matcher(tableQuery); int last = -1; while (matcher.find()) { final int start = matcher.start(); final int end = matcher.end(); last = end; if (buffer.length() <= 0) { buffer.append(tableQuery.substring(0, start)); } String key = matcher.group(); key = key.substring(1); list.add(key); buffer.append("?"); } if (last > 0 && last < tableQuery.length() - 1) { buffer.append(tableQuery.substring(last + 1)); } else if (last <= 0) { buffer.append(tableQuery); } final PreparedStatement statement = this.ensureSession().prepare(buffer.toString()); if (null == statement) { return false; } final CassandraPreparedStatement prepared = new CassandraPreparedStatement(statement, query, list); this.statementsByName.put(name, prepared); return true; } catch (final PatternSyntaxException e) { throw new NormandraException("Unable to parse query.", e); } } @Override public boolean unregisterQuery(final String name) throws NormandraException { if (null == name || name.isEmpty()) { return false; } return this.statementsByName.remove(name) != null; } @Override public void refresh() throws NormandraException { if (null == meta) { throw new NullArgumentException("database metadata"); } if (DatabaseConstruction.NONE.equals(this.constructionMode)) { return; } // create all entity tables for (final String table : meta.getTables()) { try { this.refreshEntityTable(table, meta); } catch (final Exception e) { throw new NormandraException("Unable to refresh entity table [" + table + "].", e); } } // setup any table sequence/id generators for (final EntityMeta entity : meta) { for (final Class<?> entityType : entity.getTypes()) { final AnnotationParser parser = new AnnotationParser(new BasicColumnAccessorFactory(), entityType); for (final Map.Entry<Field, GeneratedValue> entry : parser.getGenerators(entityType).entrySet()) { final Field field = entry.getKey(); final GeneratedValue generator = entry.getValue(); final String type = generator.generator(); String tableName = "id_generator"; String keyColumn = "id"; String keyValue = CaseUtils.camelToSnakeCase(entity.getTable()); String valueColumn = "value"; if (GenerationType.TABLE.equals(generator.strategy())) { for (final TableGenerator table : parser.findAnnotations(entityType, TableGenerator.class)) { if (type.equalsIgnoreCase(table.name())) { if (!table.table().isEmpty()) { tableName = table.table(); } if (!table.pkColumnName().isEmpty()) { keyColumn = table.pkColumnName(); } if (!table.pkColumnValue().isEmpty()) { keyValue = table.pkColumnValue(); } if (!table.valueColumnName().isEmpty()) { valueColumn = table.valueColumnName(); } } } } else if (GenerationType.SEQUENCE.equals(generator.strategy())) { for (final SequenceGenerator sequence : parser.findAnnotations(entityType, SequenceGenerator.class)) { if (type.equalsIgnoreCase(sequence.name())) { if (!sequence.sequenceName().isEmpty()) { keyValue = sequence.sequenceName(); } } } } else if (GenerationType.IDENTITY.equals(generator.strategy())) { throw new NormandraException( "Cassandra CQL3 does not support identity primary key generation."); } try { this.refreshTableGenerator(tableName, keyColumn, valueColumn); } catch (final Exception e) { throw new NormandraException( "Unable to refresh id generator [" + generator.generator() + "].", e); } final String fieldName = field.getName(); final ColumnMeta column = entity.findColumn(fieldName); if (column != null) { final CassandraCounterIdGenerator counter = new CassandraCounterIdGenerator(tableName, keyColumn, valueColumn, keyValue, this); entity.setGenerator(column, counter); logger.info("Set counter id generator for [" + column + "] on entity [" + entity + "]."); break; } } } } } private void refreshTableGenerator(final String table, final String keyColumn, final String valueColumn) { final List<Statement> statements = new ArrayList<>(); // drop table as required if (DatabaseConstruction.RECREATE.equals(this.constructionMode) && this.hasTable(table)) { final StringBuilder cql = new StringBuilder(); cql.append("DROP TABLE ").append(table).append(";"); statements.add(new SimpleStatement(cql.toString())); } // create table final StringBuilder cql = new StringBuilder(); cql.append("CREATE TABLE IF NOT EXISTS ").append(table).append(" (").append(IOUtils.LINE_SEPARATOR); cql.append(" ").append(keyColumn).append(" text PRIMARY KEY, "); cql.append(" ").append(valueColumn).append(" counter "); cql.append(IOUtils.LINE_SEPARATOR).append(");"); statements.add(new SimpleStatement(cql.toString())); // execute statements for (final Statement statement : statements) { this.ensureSession().execute(statement); } } private void refreshEntityTable(final String tableName, final DatabaseMeta meta) { // drop table as required if (DatabaseConstruction.RECREATE.equals(this.constructionMode) && this.hasTable(tableName)) { final StringBuilder cql = new StringBuilder(); cql.append("DROP TABLE ").append(tableName).append(";"); this.ensureSession().execute(new SimpleStatement(cql.toString())); } // build columns final Set<ColumnMeta> uniqueSet = new ArraySet<>(); final Collection<ColumnMeta> primaryColumns = new ArrayList<>(); final Collection<ColumnMeta> allColumns = new ArrayList<>(); for (final EntityMeta entity : meta) { if (tableName.equalsIgnoreCase(entity.getTable())) { for (final ColumnMeta column : entity) { if (uniqueSet.add(column)) { allColumns.add(column); if (column.isPrimaryKey()) { primaryColumns.add(column); } } } } } if (DatabaseConstruction.UPDATE.equals(this.constructionMode)) { // ensure we create base database with all keys - then update/add columns in separate comment final Statement statement = defineTable(tableName, primaryColumns); if (statement != null) { this.ensureSession().execute(statement); for (final ColumnMeta column : allColumns) { final String name = column.getName(); if (!column.isPrimaryKey() && !this.hasColumn(tableName, name)) { final String type = CassandraUtils.columnType(column); if (type != null) { final StringBuilder cql = new StringBuilder(); cql.append("ALTER TABLE ").append(tableName).append(IOUtils.LINE_SEPARATOR); cql.append("ADD ").append(name).append(" ").append(type).append(";"); this.ensureSession().execute(new SimpleStatement(cql.toString())); } } } } } else { // create table and column definitions in one command final Statement statement = defineTable(tableName, allColumns); if (statement != null) { this.ensureSession().execute(statement); for (final EntityMeta entity : meta) { if (tableName.equalsIgnoreCase(entity.getTable())) { // cassandra supports index-per-column, so find all the columns we want final List<ColumnMeta> columns = new ArrayList<>(); for (final IndexMeta index : entity.getIndexed()) { for (final ColumnMeta column : index.getColumns()) { if (entity.hasColumn(column)) { columns.add(column); } } } for (final ColumnMeta column : columns) { if (!column.isPrimaryKey()) { final StringBuilder cql = new StringBuilder(); cql.append("CREATE INDEX IF NOT EXISTS ON ").append(tableName).append(" (") .append(column.getName()).append(");"); this.ensureSession().execute(new SimpleStatement(cql.toString())); } } } } } } } @Override synchronized public void close() { if (this.session != null) { this.session.close(); this.session = null; } this.cluster.close(); this.statementsByName.clear(); this.executor.shutdownNow(); } public boolean hasKeyspace(final String ks) { return this.hasTable(ks); } public void createKeyspace(final String ks) { try (final Session instance = this.cluster.connect()) { instance.execute("CREATE KEYSPACE " + ks + " WITH strategy_class = SimpleStrategy AND strategy_options:replication_factor = 1;"); } } public void dropKeyspace(final String ks) { try (final Session instance = this.cluster.connect()) { instance.execute("DROP KEYSPACE " + ks + ";"); } } protected boolean hasTable(final String table) { final KeyspaceMetadata ksMeta = this.cluster.getMetadata().getKeyspace(this.keyspaceName); if (null == ksMeta) { return false; } final TableMetadata tblMeta = ksMeta.getTable(table); return tblMeta != null; } protected boolean hasColumn(final String table, final String column) { final KeyspaceMetadata ksMeta = this.cluster.getMetadata().getKeyspace(this.keyspaceName); if (null == ksMeta) { return false; } final TableMetadata tblMeta = ksMeta.getTable(table); if (null == tblMeta) { return false; } final ColumnMetadata colMeta = tblMeta.getColumn(column); return colMeta != null; } private Statement defineTable(final String table, final Collection<ColumnMeta> columns) { // define table final StringBuilder cql = new StringBuilder(); cql.append("CREATE TABLE ").append(table).append(" (").append(IOUtils.LINE_SEPARATOR); // define columns boolean firstColumn = true; for (final ColumnMeta column : columns) { final String name = column.getName(); final String type = CassandraUtils.columnType(column); if (type != null) { if (!firstColumn) { cql.append(",").append(IOUtils.LINE_SEPARATOR); } cql.append(name).append(" ").append(type); firstColumn = false; } } final Collection<String> keys = columns.stream().filter(Objects::nonNull).filter(ColumnMeta::isPrimaryKey) .map(ColumnMeta::getName).collect(Collectors.toList()); if (keys.isEmpty()) { // cassandra requires keys return null; } // define primary keys cql.append(",").append(IOUtils.LINE_SEPARATOR); cql.append("PRIMARY KEY ("); cql.append(StringUtils.join(keys, ", ")); cql.append(")").append(IOUtils.LINE_SEPARATOR); cql.append(");"); return new SimpleStatement(cql.toString()); } /** * per driver documentation, session is thread-safe and recommended for use * on a per-keyspace basis */ synchronized private Session ensureSession() { if (this.session != null) { return this.session; } this.ensureKeyspace(this.keyspaceName); this.session = this.cluster.connect(this.keyspaceName); return this.session; } /** * ensure keyspace exists prior to constructing database session */ synchronized private void ensureKeyspace(final String ks) { final KeyspaceMetadata meta = this.cluster.getMetadata().getKeyspace(ks); if (meta != null) { return; } try (final Session instance = this.cluster.connect()) { final StringBuilder cql = new StringBuilder(); cql.append("CREATE KEYSPACE ").append(ks) .append(" WITH replication = {'class': 'SimpleStrategy', 'replication_factor' : 1};"); instance.execute(cql.toString()); } } @Override public String getKeyspace() { return this.keyspaceName; } @Override public Session getSession() { return this.ensureSession(); } @Override public Cluster getCluster() { return this.cluster; } }