/*
* 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.resolver.util;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Set;
import org.teiid.query.sql.symbol.ElementSymbol;
/**
* This class represents both virtual and physical access patterns.
*
* If a virtual access pattern is initially unsatisfied, it may be
* transformed by RuleMergeVirtual. In this case, the history of the
* access pattern will contain its previous definitions.
*/
public class AccessPattern implements Comparable<AccessPattern>, Cloneable {
private Set<ElementSymbol> unsatisfied = new HashSet<ElementSymbol>();
private LinkedList<Collection<ElementSymbol>> history = new LinkedList<Collection<ElementSymbol>>();
public AccessPattern(Collection<ElementSymbol> elements) {
unsatisfied.addAll(elements);
history.add(elements);
}
public Collection<ElementSymbol> getCurrentElements() {
return history.getFirst();
}
public void addElementHistory(Collection<ElementSymbol> elements) {
this.history.addFirst(elements);
}
/**
* @return Returns the history.
*/
public LinkedList<Collection<ElementSymbol>> getHistory() {
return this.history;
}
/**
* @return Returns the unsatisfied.
*/
public Set<ElementSymbol> getUnsatisfied() {
return this.unsatisfied;
}
/**
* @param unstaisfied The unsatisfied to set.
*/
public void setUnsatisfied(Set<ElementSymbol> unstaisfied) {
this.unsatisfied = unstaisfied;
}
/**
* @see java.lang.Object#toString()
*/
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("Access Pattern: Unsatisfied "); //$NON-NLS-1$
sb.append(unsatisfied);
sb.append(" History "); //$NON-NLS-1$
sb.append(history);
return sb.toString();
}
@Override
public int compareTo(AccessPattern other) {
if (this.unsatisfied.size() > other.unsatisfied.size()){
return 1;
} else if (this.unsatisfied.size() < other.unsatisfied.size()){
return -1;
}
return 0;
}
/**
* @see java.lang.Object#clone()
*/
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException err) {
return null;
}
}
}