src/com/googlecode/lanterna/gui2/Container.java

   1 /*
   2  * This file is part of lanterna (http://code.google.com/p/lanterna/).
   3  *
   4  * lanterna is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Copyright (C) 2010-2015 Martin
  18  */
  19 package com.googlecode.lanterna.gui2;
  20
  21 import com.googlecode.lanterna.input.KeyStroke;
  22 import java.util.Collection;
  23
  24 /**
  25  * Container is a component that contains a collection of child components. The basic example of an implementation of
  26  * this is the {@code Panel} class which uses a layout manager to size and position the children over its area. Note
  27  * that there is no method for adding components to the container, since this depends on the implementation. In general,
  28  * composites that contains one one (or zero) children, the method for specifying the child is in {@code Composite}.
  29  * Multi-child containers are generally using the {@code Panel} implementation which has an {@code addComponent(..)}
  30  * method.
  31  * @author Martin
  32  */
  33 public interface Container extends Component {
  34
  35     /**
  36      * Returns the number of children this container currently has
  37      * @return Number of children currently in this container
  38      */
  39     int getChildCount();
  40
  41     /**
  42      * Returns collection that is to be considered a copy of the list of children contained inside of this object.
  43      * Modifying this list will not affect any internal state.
  44      * @return Child-components inside of this Container
  45      */
  46     Collection<Component> getChildren();
  47
  48     /**
  49      * Returns {@code true} if this container contains the supplied component either directly or indirectly through
  50      * intermediate containers.
  51      * @param component Component to check if it's part of this container
  52      * @return {@code true} if the component is inside this Container, otherwise {@code false}
  53      */
  54     boolean containsComponent(Component component);
  55
  56     /**
  57      * Removes the component from the container. This should remove the component from the Container's internal data
  58      * structure as well as call the onRemoved(..) method on the component itself if it was found inside the container.
  59      * @param component Component to remove from the Container
  60      * @return {@code true} if the component existed inside the container and was removed, {@code false} otherwise
  61      */
  62     boolean removeComponent(Component component);
  63
  64     /**
  65      * Given an interactable, find the next one in line to receive focus. If the interactable isn't inside this
  66      * container, this method should return {@code null}.
  67      *
  68      * @param fromThis Component from which to get the next interactable, or if
  69      *                 null, pick the first available interactable
  70      * @return The next interactable component, or null if there are no more
  71      * interactables in the list
  72      */
  73     Interactable nextFocus(Interactable fromThis);
  74
  75     /**
  76      * Given an interactable, find the previous one in line to receive focus. If the interactable isn't inside this
  77      * container, this method should return {@code null}.
  78      *
  79      * @param fromThis Component from which to get the previous interactable,
  80      *                 or if null, pick the last interactable in the list
  81      * @return The previous interactable component, or null if there are no more
  82      * interactables in the list
  83      */
  84     Interactable previousFocus(Interactable fromThis);
  85
  86     /**
  87      * If an interactable component inside this container received a keyboard event that wasn't handled, the GUI system
  88      * will recursively send the event to each parent container to give each of them a chance to consume the event.
  89      * Return {@code false} if the implementer doesn't care about this particular keystroke and it will be automatically
  90      * sent up the hierarchy the to next container. If you return {@code true}, the event will stop here and won't be
  91      * reported as unhandled.
  92      * @param key Keystroke that was ignored by the interactable inside this container
  93      * @return {@code true} if this event was handled by this container and shouldn't be processed anymore,
  94      * {@code false} if the container didn't take any action on the event and want to pass it on
  95      */
  96     boolean handleInput(KeyStroke key);
  97
  98     /**
  99      * Takes a lookup map and updates it with information about where all the interactables inside of this container
 100      * are located.
 101      * @param interactableLookupMap Interactable map to update
 102      */
 103     void updateLookupMap(InteractableLookupMap interactableLookupMap);
 104 }