org.tentackle.dbms.StatementKey Maven / Gradle / Ivy
/*
* Tentackle - https://tentackle.org.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.tentackle.dbms;
import java.util.Objects;
/**
* The statement key.
*
* The key describes the statement within its usage scope, i.e. the StatementId and using class.
* The using class is necessary to locate the prepared statement because a select method may be
* implemented in a superclass of the actual class using the statement, which may result in a
* different SQL string.
*
* As an alternative, a statement key may be expressed directly by an SQL string.
* In this case, no using class is required. Notice that ths SQL string must be
* exactly the string sent to the database backend! If there are different backends
* with different SQLs, each SQL must get its own statement key.
*
* @author harald
*/
public class StatementKey {
/**
* The global statement id.
*/
private final StatementId statementId;
/**
* The persistent object class.
*/
private final Class usingClass;
/**
* Usage variant for embedded PDOs.
*/
private final String variant;
/**
* The SQL string.
*/
private final String sql;
/**
* Creates the statement key.
*
* @param statementId the global statement id
* @param usingClass the using class
* @param variant the optional usage variant, null if none
*/
public StatementKey(StatementId statementId, Class usingClass, String variant) {
this.statementId = Objects.requireNonNull(statementId, "statementId");
this.usingClass = Objects.requireNonNull(usingClass, "usingClass");
this.variant = variant;
this.sql = null;
}
/**
* Creates the statement key.
*
* @param statementId the global statement id
* @param usingClass the using class
*/
public StatementKey(StatementId statementId, Class usingClass) {
this(statementId, usingClass, null);
}
/**
* Creates a statement key.
*
* @param sql the SQL string
*/
public StatementKey(String sql) {
this.statementId = null;
this.usingClass = null;
this.variant = null;
if (Objects.requireNonNull(sql, "sql").isEmpty()) {
throw new IllegalArgumentException("empty sql");
}
this.sql = sql;
}
/**
* Gets the statement id.
*
* @return the id, null if SQL key
*/
public StatementId getStatementId() {
return statementId;
}
/**
* Gets the using class.
*
* @return the class, null if SQL key
*/
public Class getUsingClass() {
return usingClass;
}
/**
* Gets the usage variant.
*
* @return the variant, null if none
*/
public String getVariant() {
return variant;
}
/**
* Gets the SQL string.
*
* @return the SQL, null if statement id key
*/
public String getSql() {
return sql;
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
buf.append('<');
if (sql != null) {
buf.append(sql);
}
else {
buf.append(usingClass.getSimpleName());
if (variant != null) {
buf.append('/').append(variant);
}
buf.append('#').append(statementId);
}
buf.append('>');
return buf.toString();
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
StatementKey that = (StatementKey) o;
if (!Objects.equals(statementId, that.statementId)) return false;
if (!Objects.equals(usingClass, that.usingClass)) return false;
if (!Objects.equals(variant, that.variant)) return false;
return Objects.equals(sql, that.sql);
}
@Override
public int hashCode() {
int result = statementId != null ? statementId.hashCode() : 0;
result = 31 * result + (usingClass != null ? usingClass.hashCode() : 0);
result = 31 * result + (variant != null ? variant.hashCode() : 0);
result = 31 * result + (sql != null ? sql.hashCode() : 0);
return result;
}
}