001/*
002 * Units of Measurement Implementation for Java SE
003 * Copyright (c) 2005-2017, Jean-Marie Dautelle, Werner Keil, V2COM.
004 *
005 * All rights reserved.
006 *
007 * Redistribution and use in source and binary forms, with or without modification,
008 * are permitted provided that the following conditions are met:
009 *
010 * 1. Redistributions of source code must retain the above copyright notice,
011 *    this list of conditions and the following disclaimer.
012 *
013 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions
014 *    and the following disclaimer in the documentation and/or other materials provided with the distribution.
015 *
016 * 3. Neither the name of JSR-363 nor the names of its contributors may be used to endorse or promote products
017 *    derived from this software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
020 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
021 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
022 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
023 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
026 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
028 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package tec.uom.se.format;
031
032import java.io.IOException;
033import java.text.ParsePosition;
034
035import javax.measure.Unit;
036import javax.measure.format.ParserException;
037import javax.measure.format.UnitFormat;
038
039import tec.uom.se.AbstractUnit;
040
041/**
042 * <p>
043 * This class provides the interface for formatting and parsing {@link Unit units}.
044 * </p>
045 *
046 * <p>
047 * For all metric units, the 20 SI prefixes used to form decimal multiples and sub-multiples of SI units are recognized. For example:<code>
048 *        AbstractUnit.parse("m°C").equals(MetricPrefix.MILLI(Units.CELSIUS))
049 *        AbstractUnit.parse("kW").equals(MetricPrefix.KILO(Units.WATT))</code>
050 * </p>
051 *
052 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
053 * @author <a href="mailto:units@catmedia.us">Werner Keil</a>
054 * @version 1.0.2, $Date: 2017-02-25 $
055 * @since 1.0
056 * 
057 */
058public abstract class AbstractUnitFormat implements UnitFormat {
059
060  /**
061   * Returns the {@link SymbolMap} for this unit format.
062   *
063   * @return the symbol map used by this format.
064   */
065  protected abstract SymbolMap getSymbols();
066
067  /**
068   * Formats the specified unit.
069   *
070   * @param unit
071   *          the unit to format.
072   * @param appendable
073   *          the appendable destination.
074   * @return The appendable destination passed in as {@code appendable}, with formatted text appended.
075   * @throws IOException
076   *           if an error occurs.
077   */
078  public abstract Appendable format(Unit<?> unit, Appendable appendable) throws IOException;
079
080  /**
081   * Formats an object to produce a string. This is equivalent to <blockquote> {@link #format(Unit, StringBuilder) format}<code>(unit,
082   *         new StringBuilder()).toString();</code> </blockquote>
083   *
084   * @param obj
085   *          The object to format
086   * @return Formatted string.
087   * @exception IllegalArgumentException
088   *              if the Format cannot format the given object
089   */
090  public final String format(Unit<?> unit) {
091    if (unit instanceof AbstractUnit) {
092      return format((AbstractUnit<?>) unit, new StringBuilder()).toString();
093    } else {
094      try {
095        return (this.format(unit, new StringBuilder())).toString();
096      } catch (IOException ex) {
097        throw new ParserException(ex); // Should never happen.
098      }
099    }
100  }
101
102  @Override
103  public void label(Unit<?> unit, String label) {
104    // do nothing, if subclasses want to use it, override there
105  }
106
107  /**
108   * Parses a portion of the specified <code>CharSequence</code> from the specified position to produce a unit. If there is no unit to parse
109   * {@link AbstractUnit#ONE} is returned.
110   *
111   * @param csq
112   *          the <code>CharSequence</code> to parse.
113   * @param cursor
114   *          the cursor holding the current parsing index.
115   * @return the unit parsed from the specified character sub-sequence.
116   * @throws IllegalArgumentException
117   *           if any problem occurs while parsing the specified character sequence (e.g. illegal syntax).
118   */
119  protected abstract Unit<?> parse(CharSequence csq, ParsePosition cursor) throws IllegalArgumentException;
120
121  /**
122   * Parses a portion of the specified <code>CharSequence</code> from the specified position to produce a unit. If there is no unit to parse
123   * {@link AbstractUnit#ONE} is returned.
124   *
125   * @param csq
126   *          the <code>CharSequence</code> to parse.
127   * @param index
128   *          the current parsing index.
129   * @return the unit parsed from the specified character sub-sequence.
130   * @throws IllegalArgumentException
131   *           if any problem occurs while parsing the specified character sequence (e.g. illegal syntax).
132   */
133  protected abstract Unit<?> parse(CharSequence csq, int index) throws IllegalArgumentException;
134
135  /**
136   * Convenience method equivalent to {@link #format(AbstractUnit, Appendable)} except it does not raise an IOException.
137   *
138   * @param unit
139   *          the unit to format.
140   * @param dest
141   *          the appendable destination.
142   * @return the specified <code>StringBuilder</code>.
143   */
144  final StringBuilder format(AbstractUnit<?> unit, StringBuilder dest) {
145    try {
146      return (StringBuilder) this.format(unit, (Appendable) dest);
147    } catch (IOException ex) {
148      throw new Error(ex); // Can never happen.
149    }
150  }
151
152  /**
153   * serialVersionUID
154   */
155  // private static final long serialVersionUID = -2046025267890654321L;
156}