/*
 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
package java.awt;

import sun.awt.AWTAccessor;

import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.awt.peer.ScrollPanePeer;
import java.io.Serializable;


/**
 * This class represents the state of a horizontal or vertical
 * scrollbar of a <code>ScrollPane</code>. Objects of this class are
 * returned by <code>ScrollPane</code> methods.
 *
 * @since 1.4
 */
public class ScrollPaneAdjustable implements Adjustable, Serializable {

 /**
 * The <code>ScrollPane</code> this object is a scrollbar of.
 * @serial
 */
 private ScrollPane sp;

 /**
 * Orientation of this scrollbar.
 *
 * @serial
 * @see #getOrientation
 * @see java.awt.Adjustable#HORIZONTAL
 * @see java.awt.Adjustable#VERTICAL
 */
 private int orientation;

 /**
 * The value of this scrollbar.
 * <code>value</code> should be greater than <code>minimum</code>
 * and less than <code>maximum</code>
 *
 * @serial
 * @see #getValue
 * @see #setValue
 */
 private int value;

 /**
 * The minimum value of this scrollbar.
 * This value can only be set by the <code>ScrollPane</code>.
 * <p>
 * <strong>ATTN:</strong> In current implementation
 * <code>minimum</code> is always <code>0</code>. This field can
 * only be altered via <code>setSpan</code> method and
 * <code>ScrollPane</code> always calls that method with
 * <code>0</code> for the minimum. <code>getMinimum</code> method
 * always returns <code>0</code> without checking this field.
 *
 * @serial
 * @see #getMinimum
 * @see #setSpan(int, int, int)
 */
 private int minimum;

 /**
 * The maximum value of this scrollbar.
 * This value can only be set by the <code>ScrollPane</code>.
 *
 * @serial
 * @see #getMaximum
 * @see #setSpan(int, int, int)
 */
 private int maximum;

 /**
 * The size of the visible portion of this scrollbar.
 * This value can only be set by the <code>ScrollPane</code>.
 *
 * @serial
 * @see #getVisibleAmount
 * @see #setSpan(int, int, int)
 */
 private int visibleAmount;

 /**
 * The adjusting status of the <code>Scrollbar</code>.
 * True if the value is in the process of changing as a result of
 * actions being taken by the user.
 *
 * @see #getValueIsAdjusting
 * @see #setValueIsAdjusting
 * @since 1.4
 */
 private transient boolean isAdjusting;

 /**
 * The amount by which the scrollbar value will change when going
 * up or down by a line.
 * This value should be a non negative integer.
 *
 * @serial
 * @see #getUnitIncrement
 * @see #setUnitIncrement
 */
 private int unitIncrement = 1;

 /**
 * The amount by which the scrollbar value will change when going
 * up or down by a page.
 * This value should be a non negative integer.
 *
 * @serial
 * @see #getBlockIncrement
 * @see #setBlockIncrement
 */
 private int blockIncrement = 1;

 private AdjustmentListener adjustmentListener;

 /**
 * Error message for <code>AWTError</code> reported when one of
 * the public but unsupported methods is called.
 */
 private static final String SCROLLPANE_ONLY =
 "Can be set by scrollpane only";


 /**
 * Initialize JNI field and method ids.
 */
 private static native void initIDs();

 static {
 Toolkit.loadLibraries();
 if (!GraphicsEnvironment.isHeadless()) {
 initIDs();
 }
 AWTAccessor.setScrollPaneAdjustableAccessor(new AWTAccessor.ScrollPaneAdjustableAccessor() {
 public void setTypedValue(final ScrollPaneAdjustable adj,
 final int v, final int type) {
 adj.setTypedValue(v, type);
 }
 });
 }

 /**
 * JDK 1.1 serialVersionUID.
 */
 private static final long serialVersionUID = -3359745691033257079L;


 /**
 * Constructs a new object to represent specified scrollabar
 * of the specified <code>ScrollPane</code>.
 * Only ScrollPane creates instances of this class.
 * @param sp <code>ScrollPane</code>
 * @param l <code>AdjustmentListener</code> to add upon creation.
 * @param orientation specifies which scrollbar this object represents,
 * can be either <code>Adjustable.HORIZONTAL</code>
 * or <code>Adjustable.VERTICAL</code>.
 */
 ScrollPaneAdjustable(ScrollPane sp, AdjustmentListener l, int orientation) {
 this.sp = sp;
 this.orientation = orientation;
 addAdjustmentListener(l);
 }

 /**
 * This is called by the scrollpane itself to update the
 * <code>minimum</code>, <code>maximum</code> and
 * <code>visible</code> values. The scrollpane is the only one
 * that should be changing these since it is the source of these
 * values.
 */
 void setSpan(int min, int max, int visible) {
 // adjust the values to be reasonable
 minimum = min;
 maximum = Math.max(max, minimum + 1);
 visibleAmount = Math.min(visible, maximum - minimum);
 visibleAmount = Math.max(visibleAmount, 1);
 blockIncrement = Math.max((int)(visible * .90), 1);
 setValue(value);
 }

 /**
 * Returns the orientation of this scrollbar.
 * @return the orientation of this scrollbar, either
 * <code>Adjustable.HORIZONTAL</code> or
 * <code>Adjustable.VERTICAL</code>
 */
 public int getOrientation() {
 return orientation;
 }

 /**
 * This method should <strong>NOT</strong> be called by user code.
 * This method is public for this class to properly implement
 * <code>Adjustable</code> interface.
 *
 * @throws AWTError Always throws an error when called.
 */
 public void setMinimum(int min) {
 throw new AWTError(SCROLLPANE_ONLY);
 }

 public int getMinimum() {
 // XXX: This relies on setSpan always being called with 0 for
 // the minimum (which is currently true).
 return 0;
 }

 /**
 * This method should <strong>NOT</strong> be called by user code.
 * This method is public for this class to properly implement
 * <code>Adjustable</code> interface.
 *
 * @throws AWTError Always throws an error when called.
 */
 public void setMaximum(int max) {
 throw new AWTError(SCROLLPANE_ONLY);
 }

 public int getMaximum() {
 return maximum;
 }

 public synchronized void setUnitIncrement(int u) {
 if (u != unitIncrement) {
 unitIncrement = u;
 if (sp.peer != null) {
 ScrollPanePeer peer = (ScrollPanePeer) sp.peer;
 peer.setUnitIncrement(this, u);
 }
 }
 }

 public int getUnitIncrement() {
 return unitIncrement;
 }

 public synchronized void setBlockIncrement(int b) {
 blockIncrement = b;
 }

 public int getBlockIncrement() {
 return blockIncrement;
 }

 /**
 * This method should <strong>NOT</strong> be called by user code.
 * This method is public for this class to properly implement
 * <code>Adjustable</code> interface.
 *
 * @throws AWTError Always throws an error when called.
 */
 public void setVisibleAmount(int v) {
 throw new AWTError(SCROLLPANE_ONLY);
 }

 public int getVisibleAmount() {
 return visibleAmount;
 }


 /**
 * Sets the <code>valueIsAdjusting</code> property.
 *
 * @param b new adjustment-in-progress status
 * @see #getValueIsAdjusting
 * @since 1.4
 */
 public void setValueIsAdjusting(boolean b) {
 if (isAdjusting != b) {
 isAdjusting = b;
 AdjustmentEvent e =
 new AdjustmentEvent(this,
 AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED,
 AdjustmentEvent.TRACK, value, b);
 adjustmentListener.adjustmentValueChanged(e);
 }
 }

 /**
 * Returns true if the value is in the process of changing as a
 * result of actions being taken by the user.
 *
 * @return the value of the <code>valueIsAdjusting</code> property
 * @see #setValueIsAdjusting
 */
 public boolean getValueIsAdjusting() {
 return isAdjusting;
 }

 /**
 * Sets the value of this scrollbar to the specified value.
 * <p>
 * If the value supplied is less than the current minimum or
 * greater than the current maximum, then one of those values is
 * substituted, as appropriate.
 *
 * @param v the new value of the scrollbar
 */
 public void setValue(int v) {
 setTypedValue(v, AdjustmentEvent.TRACK);
 }

 /**
 * Sets the value of this scrollbar to the specified value.
 * <p>
 * If the value supplied is less than the current minimum or
 * greater than the current maximum, then one of those values is
 * substituted, as appropriate. Also, creates and dispatches
 * the AdjustementEvent with specified type and value.
 *
 * @param v the new value of the scrollbar
 * @param type the type of the scrolling operation occurred
 */
 private void setTypedValue(int v, int type) {
 v = Math.max(v, minimum);
 v = Math.min(v, maximum - visibleAmount);

 if (v != value) {
 value = v;
 // Synchronously notify the listeners so that they are
 // guaranteed to be up-to-date with the Adjustable before
 // it is mutated again.
 AdjustmentEvent e =
 new AdjustmentEvent(this,
 AdjustmentEvent.ADJUSTMENT_VALUE_CHANGED,
 type, value, isAdjusting);
 adjustmentListener.adjustmentValueChanged(e);
 }
 }

 public int getValue() {
 return value;
 }

 /**
 * Adds the specified adjustment listener to receive adjustment
 * events from this <code>ScrollPaneAdjustable</code>.
 * If <code>l</code> is <code>null</code>, no exception is thrown
 * and no action is performed.
 * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
 * >AWT Threading Issues</a> for details on AWT's threading model.
 *
 * @param l the adjustment listener.
 * @see #removeAdjustmentListener
 * @see #getAdjustmentListeners
 * @see java.awt.event.AdjustmentListener
 * @see java.awt.event.AdjustmentEvent
 */
 public synchronized void addAdjustmentListener(AdjustmentListener l) {
 if (l == null) {
 return;
 }
 adjustmentListener = AWTEventMulticaster.add(adjustmentListener, l);
 }

 /**
 * Removes the specified adjustment listener so that it no longer
 * receives adjustment events from this <code>ScrollPaneAdjustable</code>.
 * If <code>l</code> is <code>null</code>, no exception is thrown
 * and no action is performed.
 * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
 * >AWT Threading Issues</a> for details on AWT's threading model.
 *
 * @param l the adjustment listener.
 * @see #addAdjustmentListener
 * @see #getAdjustmentListeners
 * @see java.awt.event.AdjustmentListener
 * @see java.awt.event.AdjustmentEvent
 * @since JDK1.1
 */
 public synchronized void removeAdjustmentListener(AdjustmentListener l){
 if (l == null) {
 return;
 }
 adjustmentListener = AWTEventMulticaster.remove(adjustmentListener, l);
 }

 /**
 * Returns an array of all the adjustment listeners
 * registered on this <code>ScrollPaneAdjustable</code>.
 *
 * @return all of this <code>ScrollPaneAdjustable</code>'s
 * <code>AdjustmentListener</code>s
 * or an empty array if no adjustment
 * listeners are currently registered
 *
 * @see #addAdjustmentListener
 * @see #removeAdjustmentListener
 * @see java.awt.event.AdjustmentListener
 * @see java.awt.event.AdjustmentEvent
 * @since 1.4
 */
 public synchronized AdjustmentListener[] getAdjustmentListeners() {
 return (AdjustmentListener[])(AWTEventMulticaster.getListeners(
 adjustmentListener,
 AdjustmentListener.class));
 }

 /**
 * Returns a string representation of this scrollbar and its values.
 * @return a string representation of this scrollbar.
 */
 public String toString() {
 return getClass().getName() + "[" + paramString() + "]";
 }

 /**
 * Returns a string representing the state of this scrollbar.
 * This method is intended to be used only for debugging purposes,
 * and the content and format of the returned string may vary
 * between implementations. The returned string may be empty but
 * may not be <code>null</code>.
 *
 * @return the parameter string of this scrollbar.
 */
 public String paramString() {
 return ((orientation == Adjustable.VERTICAL ? "vertical,"
 :"horizontal,")
 + "[0.."+maximum+"]"
 + ",val=" + value
 + ",vis=" + visibleAmount
 + ",unit=" + unitIncrement
 + ",block=" + blockIncrement
 + ",isAdjusting=" + isAdjusting);
 }
}