/**
* Copyright 2009 Google Inc.
*
* Licensed 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.
*
*/
package org.waveprotocol.wave.model.document.util;
import org.waveprotocol.wave.model.util.Preconditions;
/**
* Similar to a {@link Range}, except it is not canonicalised to have a start
* <= end. Instead, it has an "anchor" and a "focus", which do not have
* ordering constraints
*
* Start and end are also provided for a canonicalised view.
*
* @author danilatos@google.com (Daniel Danilatos)
*/
public final class FocusedRange {
private final int anchor;
private final int focus;
private Range range;
/**
* Construct a range
*
* @param anchor
* @param focus
*/
public FocusedRange(int anchor, int focus) {
if (anchor < 0 || focus < 0) {
Preconditions.illegalArgument("Bad focused range: (" + anchor + ", " + focus + ")");
}
this.anchor = anchor;
this.focus = focus;
}
/**
* Create from an ordered range
*
* @param range
* @param ordered
*/
public FocusedRange(Range range, boolean ordered) {
if (ordered) {
this.anchor = range.getStart();
this.focus = range.getEnd();
} else {
this.anchor = range.getEnd();
this.focus = range.getStart();
}
}
/**
* Construct a collapsed range
*
* @param collapsedAt
*/
public FocusedRange(int collapsedAt) {
this(collapsedAt, collapsedAt);
}
/**
* @return anchor location, may or may not be before the focus
*/
public int getAnchor() {
return anchor;
}
/**
* @return focus location, may or may not be before the anchor
*/
public int getFocus() {
return focus;
}
/**
* @return true if the range is collapsed
*/
public boolean isCollapsed() {
return anchor == focus;
}
/**
* @return true if the anchor is less than or equal to the focus
*/
public boolean isOrdered() {
return anchor <= focus;
}
/**
* Get an guaranteed ordered range out of the current possibly unordered
* range.
*
* The return value is cached
*/
public Range asRange() {
if (range == null) {
range = anchor < focus ? new Range(anchor, focus) : new Range(focus, anchor);
}
return range;
}
@Override
public int hashCode() {
return anchor + 37 * focus;
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (!(obj instanceof FocusedRange)) return false;
final FocusedRange other = (FocusedRange) obj;
if (focus != other.focus) return false;
if (anchor != other.anchor) return false;
return true;
}
@Override
public String toString() {
return "FocusedRange(" + getAnchor()
+ (isCollapsed() ? "" : "->" + getFocus())
+ ")";
}
}