/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.schema;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.SQLException;
import org.h2.api.ErrorCode;
import org.h2.api.Trigger;
import org.h2.command.Parser;
import org.h2.engine.Constants;
import org.h2.engine.DbObject;
import org.h2.engine.Session;
import org.h2.message.DbException;
import org.h2.message.Trace;
import org.h2.result.Row;
import org.h2.table.Table;
import org.h2.util.JdbcUtils;
import org.h2.util.SourceCompiler;
import org.h2.util.StatementBuilder;
import org.h2.util.StringUtils;
import org.h2.value.DataType;
import org.h2.value.Value;
/**
*A trigger is created using the statement
* CREATE TRIGGER
*/
public class TriggerObject extends SchemaObjectBase {
/**
* The default queue size.
*/
public static final int DEFAULT_QUEUE_SIZE = 1024;
private boolean insteadOf;
private boolean before;
private int typeMask;
private boolean rowBased;
private boolean onRollback;
// TODO trigger: support queue and noWait = false as well
private int queueSize = DEFAULT_QUEUE_SIZE;
private boolean noWait;
private Table table;
private String triggerClassName;
private String triggerSource;
private Trigger triggerCallback;
public TriggerObject(Schema schema, int id, String name, Table table) {
initSchemaObjectBase(schema, id, name, Trace.TRIGGER);
this.table = table;
setTemporary(table.isTemporary());
}
public void setBefore(boolean before) {
this.before = before;
}
public void setInsteadOf(boolean insteadOf) {
this.insteadOf = insteadOf;
}
private synchronized void load() {
if (triggerCallback != null) {
return;
}
try {
Session sysSession = database.getSystemSession();
Connection c2 = sysSession.createConnection(false);
Object obj;
if (triggerClassName != null) {
obj = JdbcUtils.loadUserClass(triggerClassName).newInstance();
} else {
obj = loadFromSource();
}
triggerCallback = (Trigger) obj;
triggerCallback.init(c2, getSchema().getName(), getName(),
table.getName(), before, typeMask);
} catch (Throwable e) {
// try again later
triggerCallback = null;
throw DbException.get(ErrorCode.ERROR_CREATING_TRIGGER_OBJECT_3, e, getName(),
triggerClassName != null ? triggerClassName : "..source..", e.toString());
}
}
private Trigger loadFromSource() {
SourceCompiler compiler = database.getCompiler();
synchronized (compiler) {
String fullClassName = Constants.USER_PACKAGE + ".trigger." + getName();
compiler.setSource(fullClassName, triggerSource);
try {
Method m = compiler.getMethod(fullClassName);
if (m.getParameterTypes().length > 0) {
throw new IllegalStateException("No parameters are allowed for a trigger");
}
return (Trigger) m.invoke(null);
} catch (DbException e) {
throw e;
} catch (Exception e) {
throw DbException.get(ErrorCode.SYNTAX_ERROR_1, e, triggerSource);
}
}
}
/**
* Set the trigger class name and load the class if possible.
*
* @param triggerClassName the name of the trigger class
* @param force whether exceptions (due to missing class or access rights)
* should be ignored
*/
public void setTriggerClassName(String triggerClassName, boolean force) {
this.setTriggerAction(triggerClassName, null, force);
}
/**
* Set the trigger source code and compile it if possible.
*
* @param source the source code of a method returning a {@link Trigger}
* @param force whether exceptions (due to syntax error)
* should be ignored
*/
public void setTriggerSource(String source, boolean force) {
this.setTriggerAction(null, source, force);
}
private void setTriggerAction(String triggerClassName, String source, boolean force) {
this.triggerClassName = triggerClassName;
this.triggerSource = source;
try {
load();
} catch (DbException e) {
if (!force) {
throw e;
}
}
}
/**
* Call the trigger class if required. This method does nothing if the
* trigger is not defined for the given action. This method is called before
* or after any rows have been processed, once for each statement.
*
* @param session the session
* @param type the trigger type
* @param beforeAction if this method is called before applying the changes
*/
public void fire(Session session, int type, boolean beforeAction) {
//rowBased=true说明是一个FOR EACH ROW触发器，这个方法是在Action前后调用的，对FOR EACH ROW触发器无效
if (rowBased || before != beforeAction || (typeMask & type) == 0) {
return;
}
load();
Connection c2 = session.createConnection(false);
boolean old = false;
if (type != Trigger.SELECT) {
old = session.setCommitOrRollbackDisabled(true);
}
Value identity = session.getLastScopeIdentity();
try {
triggerCallback.fire(c2, null, null);
} catch (Throwable e) {
throw DbException.get(ErrorCode.ERROR_EXECUTING_TRIGGER_3, e, getName(),
triggerClassName != null ? triggerClassName : "..source..", e.toString());
} finally {
if (session.getLastTriggerIdentity() != null) {
session.setLastScopeIdentity(session.getLastTriggerIdentity());
session.setLastTriggerIdentity(null);
} else {
session.setLastScopeIdentity(identity);
}
if (type != Trigger.SELECT) {
session.setCommitOrRollbackDisabled(old);
}
}
}
private static Object[] convertToObjectList(Row row) {
if (row == null) {
return null;
}
int len = row.getColumnCount();
Object[] list = new Object[len];
for (int i = 0; i < len; i++) {
list[i] = row.getValue(i).getObject();
}
return list;
}
/**
* Call the fire method of the user-defined trigger class if required. This
* method does nothing if the trigger is not defined for the given action.
* This method is called before or after a row is processed, possibly many
* times for each statement.
*
* @param session the session
* @param oldRow the old row
* @param newRow the new row
* @param beforeAction true if this method is called before the operation is
* applied
* @param rollback when the operation occurred within a rollback
* @return true if no further action is required (for 'instead of' triggers)
*/
public boolean fireRow(Session session, Row oldRow, Row newRow, boolean beforeAction, boolean rollback) {
//rowBased=false说明是一个非FOR EACH ROW触发器，这个方法是在增加、删除、修改单行的前后调用的，对非FOR EACH ROW触发器无效
if (!rowBased || before != beforeAction) {
return false;
}
if (rollback && !onRollback) {
return false;
}
load();
Object[] oldList;
Object[] newList;
boolean fire = false;
if ((typeMask & Trigger.INSERT) != 0) {
if (oldRow == null && newRow != null) {
fire = true;
}
}
if ((typeMask & Trigger.UPDATE) != 0) {
if (oldRow != null && newRow != null) {
fire = true;
}
}
if ((typeMask & Trigger.DELETE) != 0) {
if (oldRow != null && newRow == null) {
fire = true;
}
}
if (!fire) {
return false;
}
oldList = convertToObjectList(oldRow);
newList = convertToObjectList(newRow);
Object[] newListBackup;
if (before && newList != null) {
newListBackup = new Object[newList.length];
System.arraycopy(newList, 0, newListBackup, 0, newList.length);
} else {
newListBackup = null;
}
Connection c2 = session.createConnection(false);
boolean old = session.getAutoCommit();
boolean oldDisabled = session.setCommitOrRollbackDisabled(true);
Value identity = session.getLastScopeIdentity();
try {
session.setAutoCommit(false);
triggerCallback.fire(c2, oldList, newList);
if (newListBackup != null) {
for (int i = 0; i < newList.length; i++) {
Object o = newList[i];
if (o != newListBackup[i]) {
Value v = DataType.convertToValue(session, o, Value.UNKNOWN);
newRow.setValue(i, v);
}
}
}
} catch (Exception e) {
if (onRollback) {
// ignore
} else {
throw DbException.convert(e);
}
} finally {
if (session.getLastTriggerIdentity() != null) {
session.setLastScopeIdentity(session.getLastTriggerIdentity());
session.setLastTriggerIdentity(null);
} else {
session.setLastScopeIdentity(identity);
}
session.setCommitOrRollbackDisabled(oldDisabled);
session.setAutoCommit(old);
}
return insteadOf;
}
/**
* Set the trigger type.
*
* @param typeMask the type
*/
public void setTypeMask(int typeMask) {
this.typeMask = typeMask;
}
public void setRowBased(boolean rowBased) {
this.rowBased = rowBased;
}
public void setQueueSize(int size) {
this.queueSize = size;
}
public int getQueueSize() {
return queueSize;
}
public void setNoWait(boolean noWait) {
this.noWait = noWait;
}
public boolean isNoWait() {
return noWait;
}
public void setOnRollback(boolean onRollback) {
this.onRollback = onRollback;
}
@Override
public String getDropSQL() {
return null;
}
@Override
public String getCreateSQLForCopy(Table targetTable, String quotedName) { //如: quotedName = PUBLIC.MYTRIGGER1
StringBuilder buff = new StringBuilder("CREATE FORCE TRIGGER ");
buff.append(quotedName);
if (insteadOf) {
buff.append(" INSTEAD OF ");
} else if (before) {
buff.append(" BEFORE ");
} else {
buff.append(" AFTER ");
}
buff.append(getTypeNameList());
buff.append(" ON ").append(targetTable.getSQL()); //ON PUBLIC.CREATETRIGGERTEST
if (rowBased) {
buff.append(" FOR EACH ROW");
}
if (noWait) {
buff.append(" NOWAIT");
} else {
buff.append(" QUEUE ").append(queueSize);
}
//CREATE FORCE TRIGGER PUBLIC.MYTRIGGER1 BEFORE INSERT, UPDATE, DELETE, SELECT, ROLLBACK
//ON PUBLIC.CREATETRIGGERTEST NOWAIT CALL "my.test.sql.CreateTriggerTest$MyTrigger"
if (triggerClassName != null) {
buff.append(" CALL ").append(Parser.quoteIdentifier(triggerClassName));
} else {
buff.append(" AS ").append(StringUtils.quoteStringSQL(triggerSource));
}
return buff.toString();
}
public String getTypeNameList() {
StatementBuilder buff = new StatementBuilder();
if ((typeMask & Trigger.INSERT) != 0) {
buff.appendExceptFirst(", ");
buff.append("INSERT");
}
if ((typeMask & Trigger.UPDATE) != 0) {
buff.appendExceptFirst(", ");
buff.append("UPDATE");
}
if ((typeMask & Trigger.DELETE) != 0) {
buff.appendExceptFirst(", ");
buff.append("DELETE");
}
if ((typeMask & Trigger.SELECT) != 0) {
buff.appendExceptFirst(", ");
buff.append("SELECT");
}
if (onRollback) {
buff.appendExceptFirst(", ");
buff.append("ROLLBACK");
}
return buff.toString();
}
@Override
public String getCreateSQL() {
return getCreateSQLForCopy(table, getSQL());
}
@Override
public int getType() {
return DbObject.TRIGGER;
}
@Override
public void removeChildrenAndResources(Session session) {
table.removeTrigger(this);
database.removeMeta(session, getId());
if (triggerCallback != null) {
try {
triggerCallback.remove();
} catch (SQLException e) {
throw DbException.convert(e);
}
}
table = null;
triggerClassName = null;
triggerSource = null;
triggerCallback = null;
invalidate();
}
@Override
public void checkRename() {
// nothing to do
}
/**
* Get the table of this trigger.
*
* @return the table
*/
public Table getTable() {
return table;
}
/**
* Check if this is a before trigger.
*
* @return true if it is
*/
public boolean isBefore() {
return before;
}
/**
* Get the trigger class name.
*
* @return the class name
*/
public String getTriggerClassName() {
return triggerClassName;
}
public String getTriggerSource() {
return triggerSource;
}
/**
* Close the trigger.
*/
public void close() throws SQLException {
if (triggerCallback != null) {
triggerCallback.close();
}
}
/**
* Check whether this is a select trigger.
*
* @return true if it is
*/
public boolean isSelectTrigger() {
return (typeMask & Trigger.SELECT) != 0;
}
}