dmh.swing.CustomFocusTraversalPolicy.java Source code

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Here is the source code for dmh.swing.CustomFocusTraversalPolicy.java

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/**
 * Kuebiko - CustomTraversalPolicy.java
 * Copyright 2013 Dave Huffman (dave dot huffman at me dot com).
 *
 * Derived from Sun's Focus Traversal Demo:
 * http://download.oracle.com/javase/tutorial/uiswing/examples/misc/FocusTraversalDemoProject/src/misc/FocusTraversalDemo.java
 *
 * Open source under the BSD 3-Clause License.
 */
package dmh.swing;

import java.awt.Component;
import java.awt.Container;
import java.awt.FocusTraversalPolicy;
import java.util.Arrays;
import java.util.List;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;

/**
 * Custom focus traversal policy; allows for the traversal of a set of
 * components in order.
 *
 * @author davehuffman
 */
public class CustomFocusTraversalPolicy extends FocusTraversalPolicy {
    private final List<Component> components;

    public CustomFocusTraversalPolicy(Component... components) {
        this(Arrays.asList(components));
    }

    public CustomFocusTraversalPolicy(List<Component> order) {
        Preconditions.checkNotNull(order);
        Preconditions.checkArgument(!order.isEmpty());

        this.components = ImmutableList.copyOf(order);
    }

    @Override
    public Component getComponentAfter(Container focusCycleRoot, Component aComponent) {
        int idx = (components.indexOf(aComponent) + 1) % components.size();
        return components.get(idx);
    }

    @Override
    public Component getComponentBefore(Container focusCycleRoot, Component aComponent) {
        int idx = components.indexOf(aComponent) - 1;
        if (idx < 0) {
            idx = components.size() - 1;
        }
        return components.get(idx);
    }

    @Override
    public Component getDefaultComponent(Container focusCycleRoot) {
        return components.get(0);
    }

    @Override
    public Component getLastComponent(Container focusCycleRoot) {
        return Iterables.getLast(components);
    }

    @Override
    public Component getFirstComponent(Container focusCycleRoot) {
        return components.get(0);
    }
}