001    /*
002     * Copyright (C) 2010 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    
020    package org.crsh.plugin;
021    
022    import java.util.Collections;
023    import java.util.HashMap;
024    import java.util.Map;
025    import java.util.concurrent.TimeUnit;
026    
027    /**
028     * A descriptor for a configuration property.
029     *
030     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
031     * @version $Revision$
032     */
033    public abstract class PropertyDescriptor<T> {
034    
035      public static PropertyDescriptor<String> create(String name, String defaultValue, String description) {
036        return new PropertyDescriptor<String>(String.class, name, defaultValue, description) {
037          @Override
038          protected String doParse(String s) throws Exception {
039            return s;
040          }
041        };
042      }
043    
044      public static PropertyDescriptor<Integer> create(String name, Integer defaultValue, String description) {
045        return new PropertyDescriptor<Integer>(Integer.class, name, defaultValue, description) {
046          @Override
047          protected Integer doParse(String s) throws Exception {
048            return Integer.parseInt(s);
049          }
050        };
051      }
052    
053      /** . */
054      private static final Map<String, PropertyDescriptor<?>> INTERNAL_ALL = new HashMap<String, PropertyDescriptor<?>>();
055    
056      /** . */
057      public static final Map<String, PropertyDescriptor<?>> ALL = Collections.unmodifiableMap(INTERNAL_ALL);
058    
059      /** . */
060      public static final PropertyDescriptor<TimeUnit> VFS_REFRESH_UNIT = new PropertyDescriptor<TimeUnit>(TimeUnit.class, "vfs.refresh_unit", TimeUnit.SECONDS, "The refresh time unit") {
061        @Override
062        public TimeUnit doParse(String s) {
063          return TimeUnit.valueOf(s);
064        }
065      };
066    
067      /** . */
068      public static final PropertyDescriptor<Integer> VFS_REFRESH_PERIOD = PropertyDescriptor.create("vfs.refresh_period", (Integer)null, "The refresh rate period");
069    
070      /** . */
071      public final Class<T> type;
072    
073      /** . */
074      public final String name;
075    
076      /** . */
077      public final T defaultValue;
078    
079      /** . */
080      public final String description;
081    
082      /**
083       * Create a new property descriptor.
084       *
085       * @param type the property type
086       * @param name the property name
087       * @param defaultValue the default value
088       * @param description the description
089       * @throws NullPointerException if the type, name or description is null
090       */
091      protected PropertyDescriptor(Class<T> type, String name, T defaultValue, String description) throws NullPointerException {
092        if (type == null) {
093          throw new NullPointerException("No null type accepted");
094        }
095        if (name == null) {
096          throw new NullPointerException("No null name accepted");
097        }
098        if (description == null) {
099          throw new NullPointerException("No null description accepted");
100        }
101    
102        this.type = type;
103        this.name = name;
104        this.defaultValue = defaultValue;
105        this.description = description;
106    
107        //
108        INTERNAL_ALL.put(name, this);
109      }
110    
111      public final String getName() {
112        return name;
113      }
114    
115      public final String getDescription() {
116        return description;
117      }
118    
119      public final Class<T> getType() {
120        return type;
121      }
122    
123      public final T getDefaultValue() {
124        return defaultValue;
125      }
126    
127      /**
128       * Parse a string representation of a value and returns the corresponding typed value.
129       *
130       * @param s the string to parse
131       * @return the corresponding value
132       * @throws NullPointerException if the argument is null
133       * @throws IllegalArgumentException if the string value cannot be parsed for some reason
134       */
135      public final T parse(String s) throws NullPointerException, IllegalArgumentException {
136        if (s == null) {
137          throw new NullPointerException("Cannot parse null property values");
138        }
139        try {
140          return doParse(s);
141        }
142        catch (Exception e) {
143          throw new IllegalArgumentException("Illegal property value " + s, e);
144        }
145      }
146    
147      /**
148       * Parse a string representation of a value and returns the correspondig property value.
149       *
150       * @param s the string to parse
151       * @return the corresponding property
152       * @throws NullPointerException if the argument is null
153       * @throws IllegalArgumentException if the string value cannot be parsed for some reason
154       */
155      public final Property<T> toProperty(String s) throws NullPointerException, IllegalArgumentException {
156        T value = parse(s);
157        return new Property<T>(this, value);
158      }
159    
160      /**
161       * Implements the real parsing, the string argument must nto be null. The returned value must not be null
162       * instead an exception must be thrown.
163       *
164       * @param s the string to parse
165       * @return the related value
166       * @throws Exception any exception that would prevent parsing to hapen
167       */
168      protected abstract T doParse(String s) throws Exception;
169    }