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* 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
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*/
package org.teiid.query.sql.lang;
import java.util.Iterator;
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.ProcedureReservedWords;
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;
/**
* Represents a SQL Update statement of the form:
* "UPDATE <group> SET <element> = <expression>, ... [WHERE <criteria>]".
*/
public class Update extends TranslatableProcedureContainer {
/** Identifies the group to be updated. */
private GroupSymbol group;
private SetClauseList changeList = new SetClauseList();
/** optional criteria defining which row get updated. */
private Criteria criteria;
// =========================================================================
// C O N S T R U C T O R S
// =========================================================================
/**
* Constructs a default instance of this class.
*/
public Update() {
}
/**
* Return type of command.
* @return TYPE_UPDATE
*/
public int getType() {
return Command.TYPE_UPDATE;
}
/**
* Construct with group and change list
* @param group Group to by updated
* @param changeList List of CompareCriteria that represent Element->expression updates
*/
public Update(GroupSymbol group, SetClauseList changeList) {
this.group = group;
this.changeList = changeList;
}
/**
* Construct with group, change list, and criteria
* @param group DataGroupID that represents the group being updated
* @param List of changeCriteria that represent Element->value pairings
* @param criteria Criteria that defines what rows get updated
*/
public Update(GroupSymbol group, SetClauseList changeList, Criteria criteria) {
this(group, changeList);
this.criteria = criteria;
}
// =========================================================================
// M E T H O D S
// =========================================================================
/**
* Returns the group being updated
* @return Group being updated
*/
public GroupSymbol getGroup() {
return group;
}
/**
* Set the group being updated
* @param group Group being updated
*/
public void setGroup(GroupSymbol group) {
this.group = group;
}
/**
* Set the list of CompareCriteria representing updates being made
* @param changeList List of CompareCriteria
*/
public void setChangeList(SetClauseList changeList) {
this.changeList = changeList;
}
/**
* Return the list of CompareCriteria representing updates being made
* @return List of CompareCriteria
*/
public SetClauseList getChangeList() {
return this.changeList;
}
/**
* Add change to change list - a change is represented by a CompareCriteria
* internally but can be added here as an element and an expression
* @param id Element to be changed
* @param value Expression, often a value, being set
*/
public void addChange(ElementSymbol id, Expression value) {
changeList.addClause(id, value);
}
/**
* Returns the criteria object for this command, may be null
* @return Criteria, may be null
*/
public Criteria getCriteria() {
return this.criteria;
}
/**
* Set the criteria for this Update 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);
}
// =========================================================================
// P A R S E R M E T H O D S
// =========================================================================
/**
* Get hashcode for command. WARNING: This hash code relies on the hash codes of the
* Group, changeList 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 command has been
* completely constructed.
* @return Hash code
*/
public int hashCode() {
int myHash = 0;
myHash = HashCodeUtil.hashCode(myHash, this.group);
myHash = HashCodeUtil.hashCode(myHash, this.changeList);
if (this.criteria != null) {
myHash = HashCodeUtil.hashCode(myHash, this.criteria);
}
return myHash;
}
/**
* Returns a string representation of an instance of this class.
* @return String representation of object
*/
public String toString() {
return SQLStringVisitor.getSQLString(this);
}
/**
* Compare two update commands for equality. Will only evaluate to equal if
* they are IDENTICAL: group is equal, changeList contains same compareCriteria, criteria are in
* the same exact structure.
* @param obj Other object
* @return True if equal
*/
public boolean equals(Object obj) {
// Quick same object test
if(this == obj) {
return true;
}
// Quick fail tests
if(!(obj instanceof Update)) {
return false;
}
Update other = (Update) obj;
return
// Compare the groups
EquivalenceUtil.areEqual(getGroup(), other.getGroup()) &&
// Compare the changeList by checking to see if
// both objects contains exactly the same CompareCriteria objects.
getChangeList().equals(other.getChangeList()) &&
// Compare the criteria clauses
EquivalenceUtil.areEqual(getCriteria(), other.getCriteria());
}
/**
* Return a copy of this Update.
* @return Deep clone
*/
public Object clone() {
Update copy = new Update();
if(group != null) {
copy.setGroup(group.clone());
}
copy.setChangeList((SetClauseList)this.changeList.clone());
if(criteria != null) {
copy.setCriteria((Criteria) criteria.clone());
}
this.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;
}
/**
* @see org.teiid.query.sql.lang.ProcedureContainer#getProcedureParameters()
* @since 5.0
*/
public LinkedHashMap<ElementSymbol, Expression> getProcedureParameters() {
LinkedHashMap<ElementSymbol, Expression> map = new LinkedHashMap<ElementSymbol, Expression>();
for (Iterator iter = getChangeList().getClauses().iterator(); iter.hasNext();) {
SetClause setClause = (SetClause)iter.next();
ElementSymbol symbol = (ElementSymbol)(setClause.getSymbol()).clone();
symbol.setGroupSymbol(new GroupSymbol(ProcedureReservedWords.INPUTS));
map.put( symbol, setClause.getValue() );
} // for
return map;
}
}