info.unterrainer.commons.httpserver.interceptors.InterceptorParamBuilder Maven / Gradle / Ivy
package info.unterrainer.commons.httpserver.interceptors;
import java.util.function.BiConsumer;
import info.unterrainer.commons.httpserver.GenericHandlerGroupBuilder;
import info.unterrainer.commons.rdbutils.entities.BasicJpa;
import info.unterrainer.commons.serialization.jsons.BasicJson;
import lombok.RequiredArgsConstructor;
@RequiredArgsConstructor
public class InterceptorParamBuilder {
private final GenericHandlerGroupBuilder parent;
private final BiConsumer saveInterceptorData;
private String selectClause = "o";
private String joinClause = "";
private String orderByClause = "";
private String query = "";
/**
* This helps you to add something to the select-clause, like 'distinct' or a
* limit.
* The standard table always gets the alias 'o'.
*
* @param selectClause the clause (Example:
* {@code 'DISTINCT ' + ThisJpa.class.getSimpleName + ' AS o'})
* @return itself in order to provide a fluent interface.
*/
public InterceptorParamBuilder select(final String selectClause) {
this.selectClause = selectClause.trim().toLowerCase().startsWith("select")
? selectClause.trim().substring(6).trim()
: selectClause.trim();
return this;
}
/**
* Here you can specify a special join-clause that will be added to your query
* later on.
* The aliases you give here may be used in all other parts of the query.
*
* @param joinClause the clause (Example:
* {@code ' JOIN ' + MyClass.getSimpleName() + ' AS f ON o.fId=f.id'})
* @return itself in order to provide a fluent interface.
*/
public InterceptorParamBuilder join(final String joinClause) {
this.joinClause = " " + joinClause.trim();
return this;
}
/**
* Here you can specify a special order-by-clause that will be appended to your
* SQL-query later on.
*
* @param orderByClause the clause (Example: {@code 'o.name DESC'}
* @return itself in order to provide a fluent interface.
*/
public InterceptorParamBuilder orderBy(final String orderByClause) {
this.orderByClause = " " + orderByClause.trim();
return this;
}
/**
* This is where you declare your rules that will construct your query.
* Be sure to have the correct indexes placed on your tables for your queries
* to perform well.
*
* - The operators are 'AND' and 'OR' and you may use parentheses '(' and ')' to
* group your sub-expressions.
* {@code Example: 'term1 AND (term2 OR term3)'}
* - Operator precedence automatically is AND before OR.
* - A term starts with a DB-field followed by either an operator and a
* JSON-field, or a null-operator.
* - JSON-fields start with ':' and end on a bracket-expression containing the
* type of field.
* - Allowed fields are:
* {@code string, boolean, int, long, float, double and datetime} (The system
* knows how to convert these to DB-values).
* {@code Example: 'dbFieldName = :jsonName[string] AND dbId = :id[long] OR otherDbField IS NOT NULL AND anotherDbField IS NULL'}
* - When using Enums you have to specify the type of the Enum to cast to
* preceded by a '~'.
* {@code Example: 'dbEnumField = :jsonField[~MyEnumClass]'}
*
* - Term operators are: {@code >, <, >=, <=, = or ==, <> or != and LIKE} (which
* automatically adds the wildcards like %yourvalue% before going to the
* database).
* - Every term may be optional when you precede the DB-field-name with a
* '?'.
* {@code Example: '?dbFieldName = :jsonName[string] AND dbId = :id[long]' requested with an empty 'jsonName' will result in 'dbId = :id[long]'}
* Everything is case-insensitive except for the parameters of course.
*
* @param query a string that will be parsed constructing your where-clause and
* all parameter-assignments
* @return itself in order to provide a fluent interface.
*/
public InterceptorParamBuilder query(final String query) {
this.query = query;
return this;
}
/**
* Builds this Interceptor and returns you to the fluent interface of the
* underlying {@link GenericHandlerGroupBuilder}.
*
* @return the {@link GenericHandlerGroupBuilder} you came from.
*/
public GenericHandlerGroupBuilder build() {
InterceptorData r = InterceptorData.builder()
.selectClause(selectClause)
.joinClause(joinClause)
.orderByClause(orderByClause)
.build();
saveInterceptorData.accept(r, query);
return parent;
}
}