/*
* Copyright (C) 2012 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.crsh.cli.spi;
import java.io.Serializable;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
/**
* <p>An immutable object representing the complation of a value. A completion is described by:</p>
*
* <ol>
* <li>A prefix: an optional value that is relevant when more than a result is provided. The prefix value must be a
* suffix of the completion prefix, it is used to shorten the completed prefix in order to make the completions
* values shorter. For instance a path completion returning several values could be displayed in columns, however only
* the last name of the path would be displayed and not the full path.</li>
* <li>A list of <code>Map.Entry<String, Boolean></code> map where the key is string value of the completion
* and the boolean value tells whether the value is a suffix (i.e it ends the value) or not (i.e it can be further
* more completed).</li>
* </ol>
*
* <p>The following guidelines should be respected:</p>
* <ul>
* <li>An empty completion means no completion can be determined.</li>
* <li>A singleton map means the match was entire and completion will happen with the unique entry.</li>
* <li>A map containing a list of string values sharing a common prefix indicates to use this common prefix.</li>
* <li>A list containing strings with no common prefix (other than the empty string) instruct to display the list of
* possible completions. In that case the completion result prefix is used to preped the returned suffixes when
* displayed in rows.</li>
* <li>When a match is considered as entire (the entry value is set to true), the completion should contain a
* trailing value that is usually a white space (but it could be a quote for quoted values).</li>
* </ul>
*
* <p>Example: a completer that would complete colors could</p>
* <ul>
* <li>return the result ["lack ":true,"lue ":true] with the prefix "b" for the prefix "b".</li>
* <li>return the result ["e ":true] with the prefix "blu" for the prefix "blu".</li>
* <li>return the result [] for the prefix "z".</li>
* </ul>
*
* <p>Example: a completer that would complete java packages could</p>
* <ul>
* <li>return the map ["ext":true,"ext.spi":false] for the prefix "java.t"</li>
* </ul>
*/
public final class Completion implements Iterable<Map.Entry<String, Boolean>>, Serializable {
/** . */
private static final Completion EMPTY = create("");
public static Builder builder(String prefix) {
return new Builder(prefix);
}
public static Completion create() {
return EMPTY;
}
public static Completion create(String prefix) {
return create(prefix, Collections.<String, Boolean>emptyMap());
}
public static Completion create(String prefix, String suffix, boolean value) {
return create(prefix, Collections.singletonMap(suffix, value));
}
public static Completion create(String suffix, boolean value) {
return create("", suffix, value);
}
public static Completion create(String prefix, Map<String, Boolean> suffixes) {
return new Completion(prefix, suffixes);
}
/** . */
private final String prefix;
/** . */
private final Map<String, Boolean> values;
private Completion(String prefix, Map<String, Boolean> values) {
if (prefix == null) {
throw new NullPointerException("No null prefix allowed");
}
if (values == null) {
throw new NullPointerException("No null suffixes allowed");
}
//
this.prefix = prefix;
this.values = values;
}
public Iterator<Map.Entry<String, Boolean>> iterator() {
return values.entrySet().iterator();
}
public Set<String> getValues() {
return values.keySet();
}
public boolean isEmpty() {
return values.isEmpty();
}
public Boolean get(String key) {
return values.get(key);
}
public int getSize() {
return values.size();
}
public String getPrefix() {
return prefix;
}
@Override
public int hashCode() {
return prefix.hashCode() ^ values.hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof Completion) {
Completion that = (Completion)obj;
return prefix.equals(that.prefix) && values.equals(that.values);
}
return false;
}
@Override
public String toString() {
return "Completion[prefix=" + prefix + ",entries=" + values + "]";
}
public static class Builder {
/** . */
private String prefix;
/** . */
private Map<String, Boolean> entries;
public Builder(String prefix) {
this.prefix = prefix;
this.entries = null;
}
public Builder add(String key, boolean value) {
if (entries == null) {
entries = new LinkedHashMap<String, Boolean>();
}
entries.put(key, value);
return this;
}
public Completion build() {
return create(prefix, entries != null ? entries : Collections.<String, Boolean>emptyMap());
}
}
}