--- /dev/null 2013-01-18 16:17:08.886776012 -0800 +++ new/src/share/classes/java/time/temporal/TemporalQuery.java 2013-01-22 16:58:19.000000000 -0800 @@ -0,0 +1,143 @@ +/* + * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. Oracle designates this + * particular file as subject to the "Classpath" exception as provided + * by Oracle in the LICENSE file that accompanied this code. + * + * This code 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 General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +/* + * This file is available under and governed by the GNU General Public + * License version 2 only, as published by the Free Software Foundation. + * However, the following notice accompanied the original version of this + * file: + * + * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * * Neither the name of JSR-310 nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +package java.time.temporal; + +import java.time.DateTimeException; + +/** + * Strategy for querying a temporal object. + *
+ * Queries are a key tool for extracting information from temporal objects. + * They exist to externalize the process of querying, permitting different + * approaches, as per the strategy design pattern. + * Examples might be a query that checks if the date is the day before February 29th + * in a leap year, or calculates the number of days to your next birthday. + *
+ * The {@link TemporalField} interface provides another mechanism for querying + * temporal objects. That interface is limited to returning a {@code long}. + * By contrast, queries can return any type. + *
+ * There are two equivalent ways of using a {@code TemporalQuery}. + * The first is to invoke the method on this interface directly. + * The second is to use {@link TemporalAccessor#query(TemporalQuery)}: + *
+ * // these two lines are equivalent, but the second approach is recommended + * temporal = thisQuery.queryFrom(temporal); + * temporal = temporal.query(thisQuery); + *+ * It is recommended to use the second approach, {@code query(TemporalQuery)}, + * as it is a lot clearer to read in code. + *
+ * The most common implementations are method references, such as + * {@code LocalDate::from} and {@code ZoneId::from}. + * Further implementations are on {@link Queries}. + * Queries may also be defined by applications. + * + *
+ * This queries the specified temporal object to return an object using the logic + * encapsulated in the implementing class. + * Examples might be a query that checks if the date is the day before February 29th + * in a leap year, or calculates the number of days to your next birthday. + *
+ * There are two equivalent ways of using this method. + * The first is to invoke this method directly. + * The second is to use {@link TemporalAccessor#query(TemporalQuery)}: + *
+ * // these two lines are equivalent, but the second approach is recommended + * temporal = thisQuery.queryFrom(temporal); + * temporal = temporal.query(thisQuery); + *+ * It is recommended to use the second approach, {@code query(TemporalQuery)}, + * as it is a lot clearer to read in code. + * + *
+ * The input temporal object may be in a calendar system other than ISO. + * Implementations may choose to document compatibility with other calendar systems, + * or reject non-ISO temporal objects by {@link Queries#chrono() querying the chronology}. + *
+ * This method may be called from multiple threads in parallel. + * It must be thread-safe when invoked. + * + * @param temporal the temporal object to query, not null + * @return the queried value, may return null to indicate not found + * @throws DateTimeException if unable to query + * @throws ArithmeticException if numeric overflow occurs + */ + R queryFrom(TemporalAccessor temporal); + +}