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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 org.apache.fop.fo.Constants;
/**
* An instance of this class represents information about a feasible
* breaking point; it does not represent any piece of content.
*
* A KnuthPenalty is a feasible breaking point unless its value is infinity;
* a KnuthPenalty whose value is -infinity represents a forced break.
*
* A KnuthPenalty is suppressed, and its width is ignored, if it is not a
* chosen breaking point; for example, a KnuthPenalty representing a
* hyphenation point has a width (the "-" width), which must be ignored if
* that point is not chosen as a breaking point.
*
* Besides the inherited methods and attributes, this class has two more
* attributes and the methods used to get them: the penalty value, which is
* a kind of "aesthetic cost" (the higher the value, the more unsightly the
* breaking point), and a boolean that marks KnuthPenalties which should not
* be chosen as breaking points for consecutive lines.
*/
public class KnuthPenalty extends KnuthElement {
/** Used for flagged penalties. See Knuth algorithm. */
public static final int FLAGGED_PENALTY = 50;
/** Dummy, zero-width penalty */
public static final KnuthPenalty DUMMY_ZERO_PENALTY
= new KnuthPenalty(0, 0, false, null, true);
private int penalty;
private boolean penaltyFlagged;
private int breakClass = -1;
/**
* Create a new KnuthPenalty.
*
* @param width the width of this penalty
* @param penalty the penalty value of this penalty
* @param penaltyFlagged is this penalty flagged?
* @param pos the Position stored in this penalty
* @param auxiliary is this penalty auxiliary?
*/
public KnuthPenalty(int width, int penalty, boolean penaltyFlagged, Position pos,
boolean auxiliary) {
super(width, pos, auxiliary);
this.penalty = penalty;
this.penaltyFlagged = penaltyFlagged;
}
/**
* Create a new KnuthPenalty.
*
* @param width the width of this penalty
* @param penalty the penalty value of this penalty
* @param penaltyFlagged is this penalty flagged?
* @param breakClass the break class of this penalty (one of
* {@link Constants#EN_AUTO}, {@link Constants#EN_COLUMN}, {@link Constants#EN_PAGE},
* {@link Constants#EN_EVEN_PAGE}, {@link Constants#EN_ODD_PAGE})
* @param pos the Position stored in this penalty
* @param isAuxiliary is this penalty auxiliary?
*/
public KnuthPenalty(int width, int penalty, boolean penaltyFlagged, int breakClass,
Position pos, boolean isAuxiliary) {
this(width, penalty, penaltyFlagged, pos, isAuxiliary);
this.breakClass = breakClass;
}
private static String getBreakClassName(int breakClass) {
return AbstractBreaker.getBreakClassName(breakClass);
}
/**
* Get the penalty's value as a {@link java.lang.String}.
* (Mainly used in {@link #toString()} methods, to improve readability
* of the trace logs.)
*
* TODO: shouldn't be penalty a class of its own?
*
* @param penaltyValue the penalty value
* @return the penalty value as a {@link java.lang.String}
*/
protected static String valueOf(int penaltyValue) {
String result = (penaltyValue < 0) ? "-" : "";
int tmpValue = Math.abs(penaltyValue);
result += (tmpValue == KnuthElement.INFINITE)
? "INFINITE"
: String.valueOf(tmpValue);
return result;
}
/** {@inheritDoc} */
public boolean isPenalty() {
return true;
}
/**
* @return the penalty value of this penalty.
*/
public int getPenalty() {
return penalty;
}
/**
* Sets a new penalty value.
* @param penalty the new penalty value
*/
public void setPenalty(int penalty) {
this.penalty = penalty;
}
/** @return true is this penalty is a flagged one. */
public boolean isPenaltyFlagged() {
return penaltyFlagged;
}
/** {@inheritDoc} */
public boolean isForcedBreak() {
return penalty == -KnuthElement.INFINITE;
}
/**
* @return the break class of this penalty (EN_AUTO, EN_COLUMN, EN_PAGE, EN_EVEN_PAGE,
* EN_ODD_PAGE)
*/
public int getBreakClass() {
return breakClass;
}
/** {@inheritDoc} */
public String toString() {
StringBuffer buffer = new StringBuffer(64);
if (isAuxiliary()) {
buffer.append("aux. ");
}
buffer.append("penalty");
buffer.append(" p=");
buffer.append(valueOf(this.penalty));
if (this.penaltyFlagged) {
buffer.append(" [flagged]");
}
buffer.append(" w=");
buffer.append(getWidth());
if (isForcedBreak()) {
buffer.append(" (forced break, ")
.append(getBreakClassName(this.breakClass))
.append(")");
} else if (this.penalty >= 0 && this.breakClass != -1) {
//penalty corresponding to a keep constraint
buffer.append(" (keep constraint, ")
.append(getBreakClassName(this.breakClass))
.append(")");
}
return buffer.toString();
}
}
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