/* 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.activiti.engine.impl;
import java.io.Serializable;
import java.util.List;
import org.activiti.engine.ActivitiException;
import org.activiti.engine.ActivitiIllegalArgumentException;
import org.activiti.engine.ManagementService;
import org.activiti.engine.impl.cfg.ProcessEngineConfigurationImpl;
import org.activiti.engine.impl.context.Context;
import org.activiti.engine.impl.db.ListQueryParameterObject;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.interceptor.CommandExecutor;
import org.activiti.engine.query.Query;
import org.activiti.engine.query.QueryProperty;
/**
* Abstract superclass for all query types.
*
* @author Joram Barrez
*/
public abstract class AbstractQuery<T extends Query<?,?>, U> extends ListQueryParameterObject implements Command<Object>, Query<T,U>, Serializable {
private static final long serialVersionUID = 1L;
public static final String SORTORDER_ASC = "asc";
public static final String SORTORDER_DESC = "desc";
private static enum ResultType {
LIST, LIST_PAGE, SINGLE_RESULT, COUNT
}
protected transient CommandExecutor commandExecutor;
protected transient CommandContext commandContext;
protected String databaseType;
protected String orderBy;
protected ResultType resultType;
protected QueryProperty orderProperty;
public static enum NullHandlingOnOrder {
NULLS_FIRST, NULLS_LAST
}
protected NullHandlingOnOrder nullHandlingOnOrder;
protected AbstractQuery() {
parameter = this;
}
protected AbstractQuery(CommandExecutor commandExecutor) {
this.commandExecutor = commandExecutor;
}
public AbstractQuery(CommandContext commandContext) {
this.commandContext = commandContext;
}
// To be used by custom queries
public AbstractQuery(ManagementService managementService){
this(((ManagementServiceImpl) managementService).getCommandExecutor());
}
public AbstractQuery<T, U> setCommandExecutor(CommandExecutor commandExecutor) {
this.commandExecutor = commandExecutor;
return this;
}
@SuppressWarnings("unchecked")
public T orderBy(QueryProperty property) {
this.orderProperty = property;
return (T) this;
}
@SuppressWarnings("unchecked")
public T orderBy(QueryProperty property, NullHandlingOnOrder nullHandlingOnOrder) {
orderBy(property);
this.nullHandlingOnOrder = nullHandlingOnOrder;
return (T) this;
}
public T asc() {
return direction(Direction.ASCENDING);
}
public T desc() {
return direction(Direction.DESCENDING);
}
@SuppressWarnings("unchecked")
public T direction(Direction direction) {
if (orderProperty==null) {
throw new ActivitiIllegalArgumentException("You should call any of the orderBy methods first before specifying a direction");
}
addOrder(orderProperty.getName(), direction.getName(), nullHandlingOnOrder);
orderProperty = null;
nullHandlingOnOrder = null;
return (T) this;
}
protected void checkQueryOk() {
if (orderProperty != null) {
throw new ActivitiIllegalArgumentException("Invalid query: call asc() or desc() after using orderByXX()");
}
}
@SuppressWarnings("unchecked")
public U singleResult() {
this.resultType = ResultType.SINGLE_RESULT;
if (commandExecutor!=null) {
return (U) commandExecutor.execute(this);
}
return executeSingleResult(Context.getCommandContext());
}
@SuppressWarnings("unchecked")
public List<U> list() {
this.resultType = ResultType.LIST;
if (commandExecutor!=null) {
return (List<U>) commandExecutor.execute(this);
}
return executeList(Context.getCommandContext(), null);
}
@SuppressWarnings("unchecked")
public List<U> listPage(int firstResult, int maxResults) {
this.firstResult = firstResult;
this.maxResults = maxResults;
this.resultType = ResultType.LIST_PAGE;
if (commandExecutor!=null) {
return (List<U>) commandExecutor.execute(this);
}
return executeList(Context.getCommandContext(), new Page(firstResult, maxResults));
}
public long count() {
this.resultType = ResultType.COUNT;
if (commandExecutor!=null) {
return (Long) commandExecutor.execute(this);
}
return executeCount(Context.getCommandContext());
}
public Object execute(CommandContext commandContext) {
if (resultType==ResultType.LIST) {
return executeList(commandContext, null);
} else if (resultType==ResultType.SINGLE_RESULT) {
return executeSingleResult(commandContext);
} else if (resultType==ResultType.LIST_PAGE) {
return executeList(commandContext, null);
} else {
return executeCount(commandContext);
}
}
public abstract long executeCount(CommandContext commandContext);
/**
* Executes the actual query to retrieve the list of results.
* @param page used if the results must be paged. If null, no paging will be applied.
*/
public abstract List<U> executeList(CommandContext commandContext, Page page);
public U executeSingleResult(CommandContext commandContext) {
List<U> results = executeList(commandContext, null);
if (results.size() == 1) {
return results.get(0);
} else if (results.size() > 1) {
throw new ActivitiException("Query return "+results.size()+" results instead of max 1");
}
return null;
}
protected void addOrder(String column, String sortOrder, NullHandlingOnOrder nullHandlingOnOrder) {
if (orderBy==null) {
orderBy = "";
} else {
orderBy = orderBy+", ";
}
String defaultOrderByClause = column + " "+sortOrder;
if (nullHandlingOnOrder != null) {
if (nullHandlingOnOrder.equals(NullHandlingOnOrder.NULLS_FIRST)) {
if (ProcessEngineConfigurationImpl.DATABASE_TYPE_H2.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_HSQL.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_POSTGRES.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_ORACLE.equals(databaseType)) {
orderBy = orderBy + defaultOrderByClause + " NULLS FIRST";
} else if (ProcessEngineConfigurationImpl.DATABASE_TYPE_MYSQL.equals(databaseType)) {
orderBy = orderBy + "isnull(" + column +") desc," + defaultOrderByClause;
} else if (ProcessEngineConfigurationImpl.DATABASE_TYPE_DB2.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_MSSQL.equals(databaseType)) {
orderBy = orderBy + "case when " + column + " is null then 0 else 1 end," + defaultOrderByClause;
} else {
orderBy = orderBy + defaultOrderByClause;
}
} else if (nullHandlingOnOrder.equals(NullHandlingOnOrder.NULLS_LAST)) {
if (ProcessEngineConfigurationImpl.DATABASE_TYPE_H2.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_HSQL.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_POSTGRES.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_ORACLE.equals(databaseType)) {
orderBy = orderBy + column + " "+sortOrder + " NULLS LAST";
} else if (ProcessEngineConfigurationImpl.DATABASE_TYPE_MYSQL.equals(databaseType)) {
orderBy = orderBy + "isnull(" + column +") asc," + defaultOrderByClause;
} else if (ProcessEngineConfigurationImpl.DATABASE_TYPE_DB2.equals(databaseType)
|| ProcessEngineConfigurationImpl.DATABASE_TYPE_MSSQL.equals(databaseType)) {
orderBy = orderBy + "case when " + column + " is null then 1 else 0 end," + defaultOrderByClause;
} else {
orderBy = orderBy + defaultOrderByClause;
}
}
} else {
orderBy = orderBy + defaultOrderByClause;
}
}
public String getOrderBy() {
if(orderBy == null) {
return super.getOrderBy();
} else {
return orderBy;
}
}
public String getOrderByColumns() {
return getOrderBy();
}
public String getDatabaseType() {
return databaseType;
}
public void setDatabaseType(String databaseType) {
this.databaseType = databaseType;
}
}