001 /*
002 * The MIT License
003 *
004 * Copyright (c) 2012, Ninja Squad
005 *
006 * Permission is hereby granted, free of charge, to any person obtaining a copy
007 * of this software and associated documentation files (the "Software"), to deal
008 * in the Software without restriction, including without limitation the rights
009 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
010 * copies of the Software, and to permit persons to whom the Software is
011 * furnished to do so, subject to the following conditions:
012 *
013 * The above copyright notice and this permission notice shall be included in
014 * all copies or substantial portions of the Software.
015 *
016 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
017 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
018 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
019 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
020 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
021 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
022 * THE SOFTWARE.
023 */
024
025 package com.ninja_squad.dbsetup.operation;
026
027 import java.sql.Connection;
028 import java.sql.SQLException;
029 import java.sql.Statement;
030 import java.util.ArrayList;
031 import java.util.Arrays;
032 import java.util.List;
033
034 import javax.annotation.Nonnull;
035 import javax.annotation.concurrent.Immutable;
036
037 import com.ninja_squad.dbsetup.bind.BinderConfiguration;
038 import com.ninja_squad.dbsetup.util.Preconditions;
039
040 /**
041 * An operation which deletes everything from a given database table.
042 * @author JB Nizet
043 */
044 @Immutable
045 public final class DeleteAll implements Operation {
046
047 private final String table;
048
049 protected DeleteAll(String table) {
050 Preconditions.checkNotNull(table, "table may not be null");
051 this.table = table;
052 }
053
054 @Override
055 public void execute(Connection connection, BinderConfiguration configuration) throws SQLException {
056 Statement stmt = connection.createStatement();
057 try {
058 stmt.executeUpdate("delete from " + table);
059 }
060 finally {
061 stmt.close();
062 }
063 }
064
065 /**
066 * Returns an operation which deletes all the rows from the given table.
067 * @param table the table to delete everything from.
068 */
069 public static DeleteAll from(@Nonnull String table) {
070 return new DeleteAll(table);
071 }
072
073 /**
074 * Returns a composite operation which deletes all the rows from the given tables, in the same order as the
075 * tables. If A has a foreign key to B, which has a foreign key to C, tables should be listed in the following
076 * order: A, B, C. Otherwise, referential constraint will break. If there is a cycle in the dependencies, you might
077 * want to use a sequence of {@link SqlOperation} to disable the foreign key constraints, then delete everything
078 * from the tables, then use another sequence of {@link SqlOperation} to re-enable the foreign key constraints.
079 * @param tables the tables to delete everything from.
080 */
081 public static Operation from(@Nonnull String... tables) {
082 return from(Arrays.asList(tables));
083 }
084
085 /**
086 * Returns a composite operation which deletes all the rows from the given tables, in the same order as the
087 * tables. If A has a foreign key to B, which has a foreign key to C, tables should be listed in the following
088 * order: A, B, C. Otherwise, referential constraint will break. If there is a cycle in the dependencies, you might
089 * want to use a sequence of {@link SqlOperation} to disable the foreign key constraints, then delete everything
090 * from the tables, then use another sequence of {@link SqlOperation} to re-enable the foreign key constraints.
091 * @param tables the tables to delete everything from.
092 */
093 public static Operation from(@Nonnull List<String> tables) {
094 List<DeleteAll> operations = new ArrayList<DeleteAll>(tables.size());
095 for (String table : tables) {
096 operations.add(new DeleteAll(table));
097 }
098 return CompositeOperation.sequenceOf(operations);
099 }
100
101 @Override
102 public String toString() {
103 return "delete from " + table;
104 }
105
106 @Override
107 public int hashCode() {
108 return table.hashCode();
109 }
110
111 @Override
112 public boolean equals(Object obj) {
113 if (this == obj) {
114 return true;
115 }
116 if (obj == null) {
117 return false;
118 }
119 if (getClass() != obj.getClass()) {
120 return false;
121 }
122 DeleteAll other = (DeleteAll) obj;
123 return this.table.equals(other.table);
124 }
125 }