org.httprpc.sql.QueryBuilder Maven / Gradle / Ivy
/*
* 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.httprpc.sql;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* Class for programmatically constructing a SQL query.
*/
public class QueryBuilder {
private StringBuilder sqlBuilder;
private QueryBuilder(StringBuilder sqlBuilder) {
this.sqlBuilder = sqlBuilder;
}
/**
* Creates a "select" query.
*
* @param columns
* The column names.
*
* @return
* The new {@link QueryBuilder} instance.
*/
public static QueryBuilder select(String... columns) {
if (columns == null) {
throw new IllegalArgumentException();
}
StringBuilder sqlBuilder = new StringBuilder();
sqlBuilder.append("select ");
sqlBuilder.append(String.join(", ", columns));
return new QueryBuilder(sqlBuilder);
}
/**
* Appends a "from" clause to a query.
*
* @param tables
* The table names.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder from(String... tables) {
if (tables == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" from ");
sqlBuilder.append(String.join(", ", tables));
return this;
}
/**
* Appends a "join" clause to a query.
*
* @param table
* The table name.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder join(String table) {
if (table == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" join ");
sqlBuilder.append(table);
return this;
}
/**
* Appends a "left join" clause to a query.
*
* @param table
* The table name.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder leftJoin(String table) {
if (table == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" left join ");
sqlBuilder.append(table);
return this;
}
/**
* Appends a "right join" clause to a query.
*
* @param table
* The table name.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder rightJoin(String table) {
if (table == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" right join ");
sqlBuilder.append(table);
return this;
}
/**
* Appends an "on" clause to a query.
*
* @param predicate
* The predicate.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder on(String predicate) {
if (predicate == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" on ");
sqlBuilder.append(predicate);
return this;
}
/**
* Appends a "where" clause to a query.
*
* @param predicate
* The predicate.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder where(String predicate) {
if (predicate == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" where ");
sqlBuilder.append(predicate);
return this;
}
/**
* Appends an "order by" clause to a query.
*
* @param columns
* The column names.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder orderBy(String... columns) {
if (columns == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" order by ");
sqlBuilder.append(String.join(", ", columns));
return this;
}
/**
* Appends a "limit" clause to a query.
*
* @param count
* The limit count.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder limit(int count) {
if (count < 0) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" limit ");
sqlBuilder.append(count);
return this;
}
/**
* Appends a "for update" clause to a query.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder forUpdate() {
sqlBuilder.append(" for update");
return this;
}
/**
* Appends a "union" clause to a query.
*
* @param queryBuilder
* The query builder to append.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder union(QueryBuilder queryBuilder) {
sqlBuilder.append(" union ");
sqlBuilder.append(queryBuilder.toString());
return this;
}
/**
* Creates an "insert into" query.
*
* @param table
* The table name.
*
* @param values
* The values to insert.
*
* @return
* The new {@link QueryBuilder} instance.
*/
public static QueryBuilder insertInto(String table, Map values) {
if (table == null) {
throw new IllegalArgumentException();
}
if (values == null) {
throw new IllegalArgumentException();
}
StringBuilder sqlBuilder = new StringBuilder();
sqlBuilder.append("insert into ");
sqlBuilder.append(table);
sqlBuilder.append(" (");
List columns = new ArrayList<>(values.keySet());
int n = columns.size();
for (int i = 0; i < n; i++) {
if (i > 0) {
sqlBuilder.append(", ");
}
sqlBuilder.append(columns.get(i));
}
sqlBuilder.append(") values (");
for (int i = 0; i < n; i++) {
if (i > 0) {
sqlBuilder.append(", ");
}
Object value = values.get(columns.get(i));
if (value instanceof QueryBuilder) {
sqlBuilder.append("(");
sqlBuilder.append(value);
sqlBuilder.append(")");
} else {
sqlBuilder.append(encode(value));
}
}
sqlBuilder.append(")");
return new QueryBuilder(sqlBuilder);
}
/**
* Creates an "update" query.
*
* @param table
* The table name.
*
* @return
* The new {@link QueryBuilder} instance.
*/
public static QueryBuilder update(String table) {
if (table == null) {
throw new IllegalArgumentException();
}
StringBuilder sqlBuilder = new StringBuilder();
sqlBuilder.append("update ");
sqlBuilder.append(table);
return new QueryBuilder(sqlBuilder);
}
/**
* Appends a "set" command to a query.
*
* @param values
* The values to update.
*
* @return
* The {@link QueryBuilder} instance.
*/
public QueryBuilder set(Map values) {
if (values == null) {
throw new IllegalArgumentException();
}
sqlBuilder.append(" set ");
int i = 0;
for (Map.Entry entry : values.entrySet()) {
if (i > 0) {
sqlBuilder.append(", ");
}
sqlBuilder.append(entry.getKey());
sqlBuilder.append(" = ");
Object value = entry.getValue();
if (value instanceof QueryBuilder) {
sqlBuilder.append("(");
sqlBuilder.append(value);
sqlBuilder.append(")");
} else {
sqlBuilder.append(encode(value));
}
i++;
}
return this;
}
/**
* Creates a "delete from" query.
*
* @param table
* The table name.
*
* @return
* The new {@link QueryBuilder} instance.
*/
public static QueryBuilder deleteFrom(String table) {
if (table == null) {
throw new IllegalArgumentException();
}
StringBuilder sqlBuilder = new StringBuilder();
sqlBuilder.append("delete from ");
sqlBuilder.append(table);
return new QueryBuilder(sqlBuilder);
}
@Override
public String toString() {
return sqlBuilder.toString();
}
private static String encode(Object value) {
if (value instanceof String) {
String string = (String)value;
if (string.startsWith(":") || string.equals("?")) {
return string;
} else {
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append("'");
stringBuilder.append(string.replace("'", "''"));
stringBuilder.append("'");
return stringBuilder.toString();
}
} else {
return String.valueOf(value);
}
}
}
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