source: trunk/gsdl/src/phind/client/ResultCanvas.java@ 1640

/**********************************************************************
 *
 * ResultCanvas.java -- a Canvas onto which a phrase list is drawn
 *
 * Copyright 1997-2000 Gordon W. Paynter
 * Copyright 2000 The New Zealand Digital Library Project
 *
 * A component of the Greenstone digital library software
 * from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *********************************************************************/

/*********************************************************************

This class is used in the Phind java applet (Phind.java).

The results of a query are displayed on a ResultCanvas object.  Each 
line of the result is stored in a ResultItem, and the ResultCanvas 
contains a Vector of ResultItems.

Each ResultCanvas is embedded in a ResultBox alongside a Scrollbar.  
When the ResultCanvas is drawn, it looks at the scrollbar, calculates 
which ResultItems are visible, then draws them on the screen.

**********************************************************************/


import java.awt.Canvas;
import java.awt.Scrollbar;
import java.awt.Graphics;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Dimension;
import java.awt.Color;
import java.util.Vector;
import java.awt.Image;
import java.awt.Event;

import java.net.URL;
import java.applet.Applet;
import java.util.Date;

public class ResultCanvas extends Canvas {

    // Other objects associated with this 
    Phind phind;
    ResultBox parent;
    Scrollbar scrollbar;

    // fonts and font spacings to use
    Font areaPlain, areaBold;
    int lineSpacing;
 
  // The phrases to display on this canvas
    int numberOfPhrases;
    int firstPhraseDisplayed;
    int phraseSelected;
    Vector phrases;

  // the background image
    public static Image backgroundImage;


    // Create a ResultCanvas from the ResultBox which is its parent.
    ResultCanvas(ResultBox p) {

    parent = p;
    phind = p.phind;
    scrollbar = p.s;
    parent.disableScrollbar();

    areaPlain = phind.plainFont;
    areaBold  = phind.boldFont;

    lineSpacing = phind.fontSize + 2;

    phrases = new Vector();
    numberOfPhrases = 0;
    firstPhraseDisplayed = 0;
    phraseSelected = -1;
    
    if (backgroundImage == null) {
        backgroundImage = p.phind.backgroundImage;
    }

    }

    void resetCanvas( ) {
    phrases.removeAllElements();
    numberOfPhrases = 0;
    repaint();
    }


    // add a new item of input.
    // return true if successful, otherwise false.
    boolean addResultItem( ResultItem item ) {
 
    // Add a new result, in sorted order.
    // First sort key is item kind (lowest first),
    // second is frequency (highest first).
    // This is not efficient, but I don't care right now.
    int index = 0;
    while ((index < numberOfPhrases) &&
           ((item.kind > ((ResultItem) phrases.elementAt(index)).kind) ||
        ((item.kind == ((ResultItem) phrases.elementAt(index)).kind) &&
         (item.freq <= ((ResultItem) phrases.elementAt(index)).freq)))) {
        index++;
    }
    phrases.insertElementAt(item,index);
    numberOfPhrases++;
    return true;
    }


    // Make sure the more Phrases item only appears in the list
    // if it is meant to.
    void updateMorePhrasesMarker() {
    
    // System.out.println("updateMorePhrasesMarker() ");

    // look for a marker
    boolean found = false;
    int index = 0;
    while (!found && (index < numberOfPhrases)) {
        if (((ResultItem) phrases.elementAt(index)).isMorePhrases()) {
        // System.out.println("found marker at: " + index + " of " + numberOfPhrases);
        found = true;
        } else {
        index++;
        }
    }

    if (parent.expansionsRetrieved == parent.numberOfExpansions) {
        // there should be no marker
        // System.out.println("No marker needed");
        if (found) {
        // System.out.println("Remove marker");
        phrases.removeElementAt(index);
        numberOfPhrases--;
        }

    } else if (parent.expansionsRetrieved < parent.numberOfExpansions) {
        // there should be a marker
        // System.out.println("Needs marker");

        if (!found) {
        // System.out.println("Add marker");
        ResultItem ri = new ResultItem(ResultItem.morePhrases, parent.searchKey);
        addResultItem(ri);
        }
    }
    }


    // Make sure the more documents marker appears when required
    void updateMoreDocumentsMarker() {
    
    // System.out.println("updateMoreDocumentsMarker() ");

    // look for a marker
    boolean found = false;
    int index = 0;
    while (!found && (index < numberOfPhrases)) {
        if (((ResultItem) phrases.elementAt(index)).isMoreDocuments()) {
        found = true;
        } else {
        index++;
        }
    }

    if (parent.documentsRetrieved == parent.numberOfDocuments) {
        // there should be no marker
        if (found) {
        phrases.removeElementAt(index);
        numberOfPhrases--;
        }

    } else if (parent.documentsRetrieved < parent.numberOfDocuments) {
        // there should be a marker
        if (!found) {
        ResultItem ri = new ResultItem(ResultItem.moreDocuments, parent.searchKey);
        addResultItem(ri);
        }
    }
    }

      

 


    public void update(Graphics g) {
    paint(g);
    }

    public void paint(Graphics g) {

    // calculate the canvas size, margins, and spacing
    Dimension canvasSize = getSize();

    g.setFont(areaPlain);
    int space = g.getFontMetrics().stringWidth(" ");
    int margin = g.getFontMetrics().stringWidth(" 8888 ");

    int leftMargin = 0;
    int secondColumn = canvasSize.width - margin;
    int firstColumn = secondColumn - margin;
    int rightMargin = firstColumn;

    // calculate the number of values that will fit onscreen
    int visible = canvasSize.height / lineSpacing;

    // get the initial scrollbar setting
    // and calculate the first result to output
    int scrollValue = scrollbar.getValue();
    if (numberOfPhrases <= visible) {
        scrollValue = 0;
    } else if (scrollValue > (numberOfPhrases - visible)) {
        scrollValue = numberOfPhrases - visible;
    } 
    firstPhraseDisplayed = scrollValue;

    // Draw the phrase area

    // draw the background
    if (phind.showImage) {
        try {
        g.drawImage(backgroundImage, 
                leftMargin, 0, rightMargin, canvasSize.height, 
                Color.white, null);
        } catch (Exception e) {
        phind.showImage = false;
        System.err.println("ResultCanvas paint error: " + e); 
        g.setColor(Color.white);
        g.fillRect(0, 0, canvasSize.width, canvasSize.height);
        }
    } else {
        g.setColor(Color.white);
        g.fillRect(0, 0, canvasSize.width, canvasSize.height);
    }
    
    // If there are no phrases, output a brief explanation.
    if (numberOfPhrases == 0) {
        g.drawString("No phrases match this query.", leftMargin + 10, lineSpacing);
    }

    // Output each of the visible ResultItems
    ResultItem result;
    int tab, i, y = 0;
    int center = leftMargin 
        + ((rightMargin - leftMargin 
        - g.getFontMetrics().stringWidth(parent.searchPhrase)) / 2);
    
    for (i = scrollValue; 
         (i < numberOfPhrases) && (y + lineSpacing < canvasSize.height); i++) {

        // Get the resultItem to output
        result = (ResultItem) phrases.elementAt(i);
        
        // Graphics settings for drawing this line
        y += lineSpacing;
        g.setFont(areaPlain);

        // Highlight if the selected phrase.
        if (i == phraseSelected) {
        g.setColor(new Color(255, 220, 115));
        g.fillRect(leftMargin, y-lineSpacing+2, rightMargin, lineSpacing);
        g.setColor(Color.black);
        }

        // Draw the item

        if (result.isPhrase()) {
        // The item is a Phrase
        tab = center - g.getFontMetrics().stringWidth(result.prefix) - space;
        g.drawString(result.prefix, tab, y);
        g.setFont(areaBold);
        g.drawString(result.body, center, y);
        tab = center + space + g.getFontMetrics().stringWidth(result.body);
        g.setFont(areaPlain);
        g.drawString(result.suffix, tab, y);
    
        } else if (result.isDocument()){
        // The item is a URL
        g.setFont(areaPlain);
        g.setColor(Color.blue);
        tab = (rightMargin - g.getFontMetrics().stringWidth(result.body)) / 2;
        g.drawString(result.body, tab, y);
        g.setColor(Color.black);
      
        } else if (result.isMorePhrases()){
        // The item is a More documents marker
        g.setColor(new Color(255, 200, 200));
        g.fillRect(leftMargin, y-lineSpacing+2, rightMargin, lineSpacing);
        g.setColor(Color.black);

        g.setFont(areaPlain);
        tab = (rightMargin - g.getFontMetrics().stringWidth("Get more phrases")) / 2;
        g.drawString("Get more phrases", tab, y);

        } else if (result.isMoreDocuments()){
        // The item is a More documents marker
        g.setColor(new Color(150, 193, 156));
        g.fillRect(leftMargin, y-lineSpacing+2, rightMargin, lineSpacing);
        g.setColor(Color.black);

        g.setFont(areaPlain);
        tab = (rightMargin - g.getFontMetrics().stringWidth("Get more documents")) / 2;
        g.drawString("Get more documents", tab, y);

        }

    }

    // Draw the frequecy columns

    // column backgrounds
    g.setColor(new Color(235, 245, 235));
    g.fillRect(firstColumn, 0, margin, canvasSize.height);
    g.setColor(new Color(200, 220, 200));
    g.fillRect(secondColumn, 0, margin, canvasSize.height);

    // fill in the numbers
    g.setColor(Color.black);
    g.setFont(areaPlain);
    y = 0;

    for (i = scrollValue; 
         (i < numberOfPhrases) && (y + lineSpacing < canvasSize.height); i++) {
        
        // Get the resultItem to output
        result = (ResultItem) phrases.elementAt(i);
        
        // Graphics settings for drawing this line
        y += lineSpacing;

        // Write the document frequency
        if ((result.documents > 1) || result.isPhrase()) {
        g.drawString(" " + Integer.toString(result.documents), firstColumn, y);
        }

        // Write the term frequency
        if (result.freq > 0) {
        g.drawString(" " + Integer.toString(result.freq), secondColumn, y);
        }
    }

    // Adjust the scrollbar
    if (visible >= numberOfPhrases) {
        parent.disableScrollbar();
    } else {
        //System.out.println("s " + scrollValue + ", v " + visible
        //       + ", m " + (numberOfPhrases));
        scrollbar.setValues(scrollValue, visible, 0, numberOfPhrases);
        scrollbar.setBlockIncrement(visible - 1);
        scrollbar.setEnabled(true);
    }

    g.drawRect(0,0, canvasSize.width - 1, canvasSize.height - 1);
    }


    // User interaction
    //
    // All interaction with the ResultCanvas is therough mouse clicks, and
    // is handles in this method.  Note we ignore clicks that follow
    // another too closely to avoid problems with slow connections.
    public boolean handleEvent(Event event) {
    
    if (event.id == Event.MOUSE_UP) {

        // ignore actions that occur within 1 second of the last
        Date now = new Date();
        // System.out.println("Click time: " + now.toString());
        if (now.getTime() < (phind.lastQueryEndTime.getTime() + 1000)) {
        System.out.println("Ignoring click - too close to last query.");
        return true;
        }

        // which Item is selected?
        int rowSelected = event.y / lineSpacing;
        int itemSelected = rowSelected + firstPhraseDisplayed;
        ResultItem item = (ResultItem) phrases.elementAt(itemSelected);

        // System.out.println("Select: " + String.valueOf(rowSelected) );
        if (itemSelected <= numberOfPhrases) {
    
        // What do we do with the event?
        // If user clicks on a phrase, we expand the phrase
        // or send the phrase to a search engine (right click)

        if (item.isPhrase()) {
            // Expand the phrase

            phraseSelected = itemSelected;
            update(getGraphics());
      
            parent.lookupPhrase(item.rule, item.toString(), 2);

            if (event.metaDown()) { 
            // Also send to search engine
            if (phind.search_url.equals("none") || phind.search_url.equals("")) {
                System.out.println("No searching in this collection");
            } else {
                URL url;
                try { 
                url = new URL(phind.search_url + "%22" + item.toString() + "%22&");
                phind.getAppletContext().showDocument(url, "phindsearch");
                System.out.println("The query is: " + url.toString());
                } catch (Exception e) { 
                System.out.println("URL error: " + e.toString());
                }
            } 
            }

        } else if (item.isDocument()) {
            // The user clicks on a URL; display it.
            phraseSelected = itemSelected;
            update(getGraphics());

            URL url;
            try {
            String address = phind.library_address 
                + "a=d&c=" + phind.collection 
                + "&d=" + item.rule;
            url = new URL(address);
            System.out.println("URL selected: " + url.toString());
            phind.getAppletContext().showDocument(url, "phindselect");
            } catch (Exception e) {
            System.out.println("URL error: " + e.toString());
            }

        } else if (item.isMorePhrases()){
            // The user clicks on a "get more phrases" marker.
            // We have to send a new query to the host
            parent.lookupPhrase(parent.searchKey, parent.searchPhrase, 3);

        } else if (item.isMoreDocuments()){
            parent.lookupPhrase(parent.searchKey, parent.searchPhrase, 4);


        }
        repaint();
        }
    }
    return true;
    }    
  
}