001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.data.preferences;
003
004import org.openstreetmap.josm.Main;
005import org.openstreetmap.josm.data.Preferences.PreferenceChangedListener;
006import org.openstreetmap.josm.tools.CheckParameterUtil;
007import org.openstreetmap.josm.tools.bugreport.BugReport;
008
009/**
010 * This class represents a property that can be represented as String.
011 *
012 * @author Michael Zangl
013 *
014 * @param <T> The property content type.
015 * @since 10824
016 */
017public abstract class AbstractToStringProperty<T> extends AbstractProperty<T> {
018
019    /**
020     * This is a version of this property that attempts to get the property with a more specialized key and - if that fails - uses the property
021     * value as default.
022     *
023     * @author Michael Zangl
024     * @param <T> The content type
025     */
026    public static class ChildProperty<T> extends AbstractToStringProperty<T> {
027        private final AbstractToStringProperty<T> parent;
028
029        ChildProperty(AbstractToStringProperty<T> parent, String key) {
030            super(key, null);
031            CheckParameterUtil.ensureParameterNotNull(parent, "parent");
032            this.parent = parent;
033        }
034
035        @Override
036        protected void storeDefaultValue() {
037            // Default value hidden in preferences.
038        }
039
040        @Override
041        public T getDefaultValue() {
042            return parent.get();
043        }
044
045        @Override
046        protected T fromString(String string) {
047            return parent.fromString(string);
048        }
049
050        @Override
051        protected String toString(T t) {
052            return parent.toString(t);
053        }
054
055        @Override
056        protected void addListenerImpl(PreferenceChangedListener adapter) {
057            super.addListenerImpl(adapter);
058            parent.addListenerImpl(adapter);
059        }
060
061        @Override
062        protected void addWeakListenerImpl(PreferenceChangedListener adapter) {
063            super.addWeakListenerImpl(adapter);
064            parent.addWeakListenerImpl(adapter);
065        }
066
067        @Override
068        protected void removeListenerImpl(PreferenceChangedListener adapter) {
069            super.removeListenerImpl(adapter);
070            parent.removeListenerImpl(adapter);
071        }
072
073        @Override
074        public CachingProperty<T> cached() {
075            throw new UnsupportedOperationException("Not implemented yet.");
076        }
077    }
078
079    /**
080     * Create a new property and store the default value.
081     * @param key The key
082     * @param defaultValue The default value.
083     * @see AbstractProperty#AbstractProperty(String, Object)
084     */
085    public AbstractToStringProperty(String key, T defaultValue) {
086        super(key, defaultValue);
087        storeDefaultValue();
088    }
089
090    @Override
091    public T get() {
092        String string = getAsString();
093        if (!string.isEmpty()) {
094            try {
095                return fromString(string);
096            } catch (InvalidPreferenceValueException e) {
097                Main.warn(BugReport.intercept(e).put("key", key).put("value", string));
098            }
099        }
100        return getDefaultValue();
101    }
102
103    /**
104     * Converts the string to an object of the given type.
105     * @param string The string
106     * @return The object.
107     * @throws InvalidPreferenceValueException If the value could not be converted.
108     */
109    protected abstract T fromString(String string);
110
111    @Override
112    public boolean put(T value) {
113        String string = value == null ? null : toString(value);
114        return getPreferences().put(getKey(), string);
115    }
116
117    /**
118     * Converts the string to an object of the given type.
119     * @param t The object.
120     * @return The string representing the object
121     * @throws InvalidPreferenceValueException If the value could not be converted.
122     */
123    protected abstract String toString(T t);
124
125    /**
126     * Gets the preference value as String.
127     * @return The string preference value.
128     */
129    protected String getAsString() {
130        T def = getDefaultValue();
131        return getPreferences().get(key, def == null ? "" : toString(def));
132    }
133
134    /**
135     * Gets a specialized setting value that has the current value as default
136     * <p>
137     * The key will be getKey().spec
138     * @param spec The key specialization
139     * @return The property
140     */
141    public AbstractToStringProperty<T> getSpecialized(String spec) {
142        return getChildProperty(getKey() + "." + spec);
143    }
144
145    /**
146     * Gets a setting that defaults to this setting if the key is not set.
147     * @param key The more specialized key.
148     * @return The new setting.
149     */
150    protected AbstractToStringProperty<T> getChildProperty(String key) {
151        return new ChildProperty<>(this, key);
152    }
153
154    /**
155     * Creates a new {@link CachingProperty} instance for this property.
156     * @return The new caching property instance.
157     */
158    public CachingProperty<T> cached() {
159        return new CachingProperty<>(this);
160    }
161}