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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
/* $Id$ */
package org.apache.fop.layoutmgr;
import java.util.LinkedList;
import java.util.List;
/**
* An alternative has a set of fitness traits (e.g. occupied bpd and ipd,
* adjustment ratio, remaining size, etc.) that determine how good its
* eligibility is when evaluated by a fitting strategy.
*/
public class Alternative {
/** Remaining BPD after inserting the alternative. */
private int remainingBPD;
/** Size of the alternative in block-progression-direction. */
private final int length;
private final List<ListElement> knuthList;
private boolean enabled = true;
public Alternative(List<ListElement> knuthList, int length) {
this.knuthList = knuthList;
this.length = length;
this.remainingBPD = 0;
}
public List<ListElement> getKnuthList() {
return knuthList;
}
public int getRemainingBPD() {
return remainingBPD;
}
public int getLength() {
return length;
}
public void setRemainingBPD(int remainingBPD) {
this.remainingBPD = remainingBPD;
}
public void setEnabled(boolean enabled) {
this.enabled = enabled;
}
public boolean isEnabled() {
return enabled;
}
public static enum FittingStrategy {
FIRST_FIT("first-fit") {
@Override
public List<Alternative> filter(List<Alternative> alternatives) {
List<Alternative> alts = new LinkedList<Alternative>();
for (Alternative alt : alternatives) {
if (alt.isEnabled()) {
alts.add(alt);
break;
}
}
return alts;
}
},
SMALLEST_FIT("smallest-fit") {
@Override
public List<Alternative> filter(List<Alternative> alternatives) {
int biggestDiff = -Integer.MAX_VALUE;
Alternative bestAlt = null;
for (Alternative alt : alternatives) {
if (alt.isEnabled() && alt.getRemainingBPD() > biggestDiff) {
biggestDiff = alt.getRemainingBPD();
bestAlt = alt;
}
}
List<Alternative> alts = new LinkedList<Alternative>();
alts.add(bestAlt);
return alts;
}
},
BIGGEST_FIT("biggest-fit") {
@Override
public List<Alternative> filter(List<Alternative> alternatives) {
int smallestDiff = Integer.MAX_VALUE;
Alternative bestAlt = null;
for (Alternative alt : alternatives) {
if (alt.isEnabled() && alt.getRemainingBPD() < smallestDiff) {
smallestDiff = alt.getRemainingBPD();
bestAlt = alt;
}
}
List<Alternative> alts = new LinkedList<Alternative>();
alts.add(bestAlt);
return alts;
}
},
ANY("any") {
@Override
public List<Alternative> filter(List<Alternative> alternatives) {
List<Alternative> alts = new LinkedList<Alternative>();
int remainingSpace = Integer.MAX_VALUE;
for (Alternative alt : alternatives) {
if (alt.isEnabled() && alt.getLength() <= remainingSpace) {
alts.add(alt);
remainingSpace = alt.getRemainingBPD();
}
}
return alts;
}
};
private String strategyName;
FittingStrategy(String strategyName) {
this.strategyName = strategyName;
}
public String getStrategyName() {
return strategyName;
}
public static FittingStrategy make(String strategyName) {
for (FittingStrategy fs : FittingStrategy.values()) {
if (fs.getStrategyName().equals(strategyName)) {
return fs;
}
}
return null;
}
/**
* @param alternatives the list of potential candidate {@link Alternative}
* @return the best alternative according to the strategy being employed
*/
public abstract List<Alternative> filter(List<Alternative> alternatives);
}
}
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