objectlist.java

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/*
 * Created on 17-Jul-2003
 *
 * To change the template for this generated file go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
package org.jfree.util;

/**
 * A list of objects that can grow as required.
 * 
 * @author David Gilbert
 */
public class ObjectList {

    /** The default initial capacity of the list. */
    public static final int DEFAULT_INITIAL_CAPACITY = 8;
    
    /** Storage for the objects. */
    private Object[] objects;
    
    /**
     * Default constructor.
     */
    public ObjectList() {
        this(DEFAULT_INITIAL_CAPACITY);
    }
    
    /**
     * Creates a new list.
     * 
     * @param initialCapacity  the initial capacity.
     */
    public ObjectList(int initialCapacity) {
        this.objects = new Object[initialCapacity];
    }
    
    /**
     * Returns the object at the specified index, if there is one, or <code>null</code>.
     *
     * @param index  the object index.
     * 
     * @return The object or <code>null</code>.
     */
    public Object get(int index) {
        Object result = null;
        if (index >= 0 && index < this.objects.length) {
            result = this.objects[index];
        }
        return result;
    }
    
    /**
     * Sets an object reference (overwriting any existing object).
     * 
     * @param index  the object index.
     * @param object  the object (<code>null</code> permitted).
     */
    public void set(int index, Object object) {
        if (index < 0) {
            throw new IllegalArgumentException("ObjectList.set(...): index must be >= 0.");
        }
        if (index >= this.objects.length) {
            Object enlarged = new Object[index];
            System.arraycopy(this.objects, 0, enlarged, 0, this.objects.length);
        }
        this.objects[index] = object;
    }
    
    /**
     * Clears the list.
     */
    public void clear() {
        this.objects = new Object[DEFAULT_INITIAL_CAPACITY];
    }
        
    /**
     * Returns the size of the list. 
     * 
     * @return The size of the list.
     */
    public int size() {
        return this.objects.length;
    }
    
    /**
     * Returns the index of the specified object, or -1 if the object is not in the list.
     * 
     * @param object  the object.
     * 
     * @return The index or -1.
     */
    public int indexOf(Object object) {
        int result = -1;
        int index = 0;
        boolean done = false;
        while (!done) {
            if (index >= this.objects.length) {
                done = true;
            }
            else if (this.objects[index] == object) {
                result = index;
                done = true;
            }
            else {
                index = index + 1;
            }
        }
        return result;
    }
    
}