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/*
* Copyright 2006 Amazon Technologies, Inc. or its affiliates.
* Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
* of Amazon Technologies, Inc. or its affiliates. All rights reserved.
*
* 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 com.amazon.carbonado.info;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;
import org.cojen.util.WeakCanonicalSet;
import com.amazon.carbonado.Storable;
import com.amazon.carbonado.util.Appender;
/**
* Represents a property paired with a preferred ordering direction.
*
* @author Brian S O'Neill
*/
public class OrderedProperty<S extends Storable> implements Serializable, Appender {
private static final long serialVersionUID = 1L;
static WeakCanonicalSet cCanonical = new WeakCanonicalSet();
/**
* Returns a canonical instance.
*
* @throws IllegalArgumentException if property is null
*/
public static <S extends Storable> OrderedProperty<S> get(StorableProperty<S> property,
Direction direction) {
return get(ChainedProperty.get(property), direction);
}
/**
* Returns a canonical instance.
*
* @throws IllegalArgumentException if property is null
*/
@SuppressWarnings("unchecked")
public static <S extends Storable> OrderedProperty<S> get(ChainedProperty<S> property,
Direction direction) {
return (OrderedProperty<S>) cCanonical.put(new OrderedProperty<S>(property, direction));
}
/**
* Parses an ordering property, which may start with a '+' or '-' to
* indicate direction. Prefix of '~' indicates unspecified direction. If
* ordering prefix not specified, default direction is ascending.
*
* @param info Info for Storable type containing property
* @param str string to parse
* @throws IllegalArgumentException if any required parameter is null or
* string format is incorrect
*/
public static <S extends Storable> OrderedProperty<S> parse(StorableInfo<S> info,
String str)
throws IllegalArgumentException
{
return parse(info, str, Direction.ASCENDING);
}
/**
* Parses an ordering property, which may start with a '+' or '-' to
* indicate direction. Prefix of '~' indicates unspecified direction.
*
* @param info Info for Storable type containing property
* @param str string to parse
* @param defaultDirection default direction if not specified in
* string. If null, ascending order is defaulted.
* @throws IllegalArgumentException if any required parameter is null or
* string format is incorrect
*/
public static <S extends Storable> OrderedProperty<S> parse(StorableInfo<S> info,
String str,
Direction defaultDirection)
throws IllegalArgumentException
{
if (info == null || str == null || defaultDirection == null) {
throw new IllegalArgumentException();
}
Direction direction = defaultDirection;
if (str.length() > 0) {
if (str.charAt(0) == '+') {
direction = Direction.ASCENDING;
str = str.substring(1);
} else if (str.charAt(0) == '-') {
direction = Direction.DESCENDING;
str = str.substring(1);
} else if (str.charAt(0) == '~') {
direction = Direction.UNSPECIFIED;
str = str.substring(1);
}
}
if (direction == null) {
direction = Direction.ASCENDING;
}
return get(ChainedProperty.parse(info, str), direction);
}
private final ChainedProperty<S> mProperty;
private final Direction mDirection;
private OrderedProperty(ChainedProperty<S> property, Direction direction) {
if (property == null) {
throw new IllegalArgumentException();
}
mProperty = property;
mDirection = direction == null ? Direction.UNSPECIFIED : direction;
}
public ChainedProperty<S> getChainedProperty() {
return mProperty;
}
public Direction getDirection() {
return mDirection;
}
public OrderedProperty<S> reverse() {
if (mDirection == Direction.UNSPECIFIED) {
return this;
}
return get(mProperty, mDirection.reverse());
}
public OrderedProperty<S> direction(Direction direction) {
return get(mProperty, direction);
}
@Override
public int hashCode() {
return mProperty.hashCode() + mDirection.hashCode();
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof OrderedProperty) {
OrderedProperty<?> other = (OrderedProperty<?>) obj;
return mProperty.equals(other.mProperty) && mDirection.equals(other.mDirection);
}
return false;
}
/**
* Returns the chained property in a parseable form.
*/
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
buf.append(mDirection.toCharacter());
try {
mProperty.appendTo(buf);
} catch (IOException e) {
// Not gonna happen.
}
return buf.toString();
}
public void appendTo(Appendable app) throws IOException {
app.append(mDirection.toCharacter());
mProperty.appendTo(app);
}
private Object readResolve() {
return get(mProperty, mDirection);
}
}
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