/*
 * @(#)InputMap.java	1.9 00/02/02
 *
 * Copyright 1999, 2000 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */
package javax.swing;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Set;

/**
 * <code>InputMap</code> provides a binding between an input event
 * (currently only <code>KeyStroke</code>s are used)
 * and an <code>Object</code>. <code>InputMap</code>s
 * are usually used with an <code>ActionMap</code>,
 * to determine an <code>Action</code> to perform
 * when a key is pressed.
 * An <code>InputMap</code> can have a parent
 * that is searched for bindings not defined in the <code>InputMap</code>.
 * <p>As with <code>ActionMap</code> if you create a cycle, eg:
 * <pre>
 *   InputMap am = new InputMap();
 *   InputMap bm = new InputMap():
 *   am.setParent(bm);
 *   bm.setParent(am);
 * </pre>
 * some of the methods will cause a StackOverflowError to be thrown.
 *
 * @version 1.9 02/02/00
 * @author Scott Violet
 * @since 1.3
 */
public class InputMap implements Serializable {
    /** Handles the mapping between KeyStroke and Action name. */
    private transient AbstractAction.ArrayTable     arrayTable;
    /** Parent that handles any bindings we don't contain. */
    private InputMap                                parent;


    /** 
     * Creates an <code>InputMap</code> with no parent and no mappings.
     */
    public InputMap() {
    }

    /**
     * Sets this <code>InputMap</code>'s parent.
     *
     * @param map  the <code>InputMap</code> that is the parent of this one
     */
    public void setParent(InputMap map) {
	this.parent = map;
    }

    /**
     * Gets this <code>InputMap</code>'s parent.
     *
     * @return map  the <code>InputMap</code> that is the parent of this one,
     *              or null if this <code>InputMap</code> has no parent
     */
    public InputMap getParent() {
	return parent;
    }

    /**
     * Adds a binding for <code>keyStroke</code> to <code>actionMapKey</code>.
     * If <code>actionMapKey</code> is null, this removes the current binding
     * for <code>keyStroke</code>.
     */
    public void put(KeyStroke keyStroke, Object actionMapKey) {
	if (keyStroke == null) {
	    return;
	}
	if (actionMapKey == null) {
	    remove(keyStroke);
	}
	else {
	    if (arrayTable == null) {
		arrayTable = new AbstractAction.ArrayTable();
	    }
	    arrayTable.put(keyStroke, actionMapKey);
	}
    }

    /**
     * Returns the binding for <code>keyStroke</code>, messaging the 
     * parent <code>InputMap</code> if the binding is not locally defined.
     */
    public Object get(KeyStroke keyStroke) {
	if (arrayTable == null) {
	    InputMap    parent = getParent();

	    if (parent != null) {
		return parent.get(keyStroke);
	    }
	    return null;
	}
	Object value = arrayTable.get(keyStroke);

	if (value == null) {
	    InputMap    parent = getParent();

	    if (parent != null) {
		return parent.get(keyStroke);
	    }
	}
	return value;
    }

    /**
     * Removes the binding for <code>key</code> from this
     * <code>InputMap</code>.
     */
    public void remove(KeyStroke key) {
	if (arrayTable != null) {
	    arrayTable.remove(key);
	}
    }

    /**
     * Removes all the mappings from this <code>InputMap</code>.
     */
    public void clear() {
	if (arrayTable != null) {
	    arrayTable.clear();
	}
    }

    /**
     * Returns the <code>KeyStroke</code>s that are bound in this <code>InputMap</code>.
     */
    public KeyStroke[] keys() {
	if (arrayTable == null) {
	    return null;
	}
	KeyStroke[] keys = new KeyStroke[arrayTable.size()];
	arrayTable.getKeys(keys);
	return keys;
    }

    /**
     * Returns the number of <code>KeyStroke</code> bindings.
     */
    public int size() {
	if (arrayTable == null) {
	    return 0;
	}
	return arrayTable.size();
    }

    /**
     * Returns an array of the <code>KeyStroke</code>s defined in this 
     * <code>InputMap</code> and its parent. This differs from <code>keys()</code> in that
     * this method includes the keys defined in the parent.
     */
    public KeyStroke[] allKeys() {
	int             count = size();
	InputMap        parent = getParent();

	if (count == 0) {
	    if (parent != null) {
		return parent.allKeys();
	    }
	    return keys();
	}
	if (parent == null) {
	    return keys();
	}
	KeyStroke[]    keys = keys();
	KeyStroke[]    pKeys =  parent.allKeys();

	if (pKeys == null) {
	    return keys;
	}
	if (keys == null) {
	    // Should only happen if size() != keys.length, which should only
	    // happen if mutated from multiple threads (or a bogus subclass).
	    return pKeys;
	}

	HashMap        keyMap = new HashMap();
	int            counter;

	for (counter = keys.length - 1; counter >= 0; counter--) {
	    keyMap.put(keys[counter], keys[counter]);
	}
	for (counter = pKeys.length - 1; counter >= 0; counter--) {
	    keyMap.put(pKeys[counter], pKeys[counter]);
	}

	KeyStroke[]    allKeys = new KeyStroke[keyMap.size()];

	return (KeyStroke[])keyMap.keySet().toArray(allKeys);
    }

    private void writeObject(ObjectOutputStream s) throws IOException {
        s.defaultWriteObject();
	KeyStroke[] keys = keys();
	// Determine valid count
	int validCount = 0;
	if (keys != null) {
	    for(int counter = 0; counter < keys.length; counter++) {
		Object value = get(keys[counter]);
		if (value instanceof Serializable) {
		    validCount++;
		}
		else {
		    keys[counter] = null;
		}
	    }
	}
	s.writeInt(validCount);
	int counter = 0;
	while (validCount > 0) {
	    if (keys[counter] != null) {
		s.writeObject(keys[counter]);
		s.writeObject(get(keys[counter]));
		validCount--;
	    }
	    counter++;
	}
    }

    private void readObject(ObjectInputStream s) throws ClassNotFoundException,
	                                         IOException {
        s.defaultReadObject();
	for (int counter = s.readInt() - 1; counter >= 0; counter--) {
	    put((KeyStroke)s.readObject(), s.readObject());
	}
    }
}