/*
* JBoss, Home of Professional Open Source.
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
package org.teiid.query.sql.lang;
import java.util.LinkedHashMap;
import java.util.List;
import org.teiid.core.util.EquivalenceUtil;
import org.teiid.core.util.HashCodeUtil;
import org.teiid.query.sql.LanguageVisitor;
import org.teiid.query.sql.symbol.ElementSymbol;
import org.teiid.query.sql.symbol.Expression;
import org.teiid.query.sql.symbol.GroupSymbol;
import org.teiid.query.sql.visitor.SQLStringVisitor;
/**
* This class represents a SQL Delete statement of the form:
* "DELETE FROM <group> [WHERE <criteria>]".
* Implements Command interface.
*/
public class Delete extends TranslatableProcedureContainer {
/** Identifies the group to delete data from. */
private GroupSymbol group;
/** The criteria specifying constraints on what data will be deleted. */
private Criteria criteria;
/**
* Constructs a default instance of this class.
*/
public Delete() {
}
/**
* Return type of command.
* @return {@link Command#TYPE_DELETE}
*/
public int getType() {
return Command.TYPE_DELETE;
}
/**
* Constructs an instance of this class given the group.
* @param group Identifier of the group to delete data from.
*/
public Delete(GroupSymbol group) {
this.group = group;
}
/**
* Constructs an instance of this class given the group and criteria.
* @param group Identifier of the group to delete data from.
* @param criteria The criteria specifying constraints on what data will be deleted.
*/
public Delete(GroupSymbol group, Criteria criteria) {
this(group);
this.criteria = criteria;
}
// =========================================================================
// M E T H O D S
// =========================================================================
/**
* Returns the group being deleted from
* @return Group symbol
*/
public GroupSymbol getGroup() {
return group;
}
/**
* Set the group for this Delete command
* @param group Group to be associated with this command
*/
public void setGroup(GroupSymbol group) {
this.group = group;
}
/**
* Returns the criteria object for this command.
* @return criteria
*/
public Criteria getCriteria() {
return this.criteria;
}
/**
* Set the criteria for this Delete command
* @param criteria Criteria to be associated with this command
*/
public void setCriteria(Criteria criteria) {
this.criteria = criteria;
}
public void acceptVisitor(LanguageVisitor visitor) {
visitor.visit(this);
}
/**
* Get hashcode for command. WARNING: This hash code relies on the hash codes of the
* Group and Criteria clause. If the command changes, it's hash code will change and
* it can be lost from collections. Hash code is only valid after the command has been
* completely constructed.
*/
public int hashCode() {
int myHash = 0;
myHash = HashCodeUtil.hashCode(myHash, this.group);
if (this.criteria != null) {
myHash = HashCodeUtil.hashCode(myHash, this.criteria);
}
return myHash;
}
/**
* Returns a string representation of an instance of this class.
* @return Command in string form
*/
public String toString() {
return SQLStringVisitor.getSQLString(this);
}
/**
* Compare two commands for equality. Will only evaluate to equal if
* they are IDENTICAL: group is the same, criteria are in
* the same exact structure.
*/
public boolean equals(Object obj) {
// Quick same object test
if(this == obj) {
return true;
}
// Quick fail tests
if(!(obj instanceof Delete)) {
return false;
}
Delete other = (Delete) obj;
return EquivalenceUtil.areEqual(getGroup(), other.getGroup()) &&
EquivalenceUtil.areEqual(getCriteria(), other.getCriteria());
}
/**
* @see org.teiid.query.sql.lang.ProcedureContainer#getParameters()
* @since 5.0
*/
public LinkedHashMap<ElementSymbol, Expression> getProcedureParameters() {
return new LinkedHashMap<ElementSymbol, Expression>();
}
/**
* Return a copy of this Delete.
*/
public Object clone() {
GroupSymbol copyGroup = null;
if(group != null) {
copyGroup = group.clone();
}
Criteria copyCrit = null;
if(criteria != null) {
copyCrit = (Criteria) criteria.clone();
}
Delete copy = new Delete(copyGroup, copyCrit);
copyMetadataState(copy);
return copy;
}
/**
* Get the ordered list of all elements returned by this query. These elements
* may be ElementSymbols or ExpressionSymbols but in all cases each represents a
* single column.
* @return Ordered list of SingleElementSymbol
*/
public List getProjectedSymbols(){
return Command.getUpdateCommandSymbol();
}
/**
* @see org.teiid.query.sql.lang.Command#areResultsCachable()
*/
public boolean areResultsCachable() {
return false;
}
}