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package net.sf.cuf.state.ui;

import net.sf.cuf.state.State;

import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.JTextComponent;

/**
 * The SwingDocumentState class models a State with the Document of a
 * Swing JTextField or JTextComponent as the state source. The value
 * of the state is determined by comparing the Document's string with
 * a user-defined string. If the string matches the document, the
 * state is true.
 * To avoid a "broadcast storm" of firing SwingDocumentState's, a
 * SwingDocumentState can be switched to "silent", in that case it
 * ignores all changes.
 */
public class SwingDocumentState extends AbstractSwingState implements State, DocumentListener
{
    /** content we compare the model to, never null */
    private String            mContent;
    /** the docment model we are watching, never null */
    private Document          mDocument;

    /**
     * Creates a new state, using the handed text field as its state source.
     * If the content  of the text field matches "" (= it is empty), then the
     * state is true.
     * @param pTextField text field we take the document from
     */
    public SwingDocumentState(final JTextComponent pTextField)
    {
        this(pTextField, "");
    }

    /**
     * Creates a new state, using the handed text field as its state source.
     * If the content  of the text field matches pContent, then the state is
     * true
     * @param pTextField text field we take the document from
     * @param pContent string to compare to
     */
    public SwingDocumentState(final JTextComponent pTextField, final String pContent)
    {
        super();
        if (pTextField==null)
        {
            throw new IllegalArgumentException("textfield must not be null");
        }
        if (pContent==null)
        {
            throw new IllegalArgumentException("compare content must not be null");
        }
        mContent= pContent;

        // initially set the state according to the document
        mDocument= pTextField.getDocument();
        mIsEnabled   = getInternalState();
        mName    = pTextField.getName();
        if (mName==null)
        {
            mName= "";
        }

        mDocument.addDocumentListener(this);
    }

    /**
     * Sets the string we compare the document against.
     * @param pContent string we compare our document to, must not be null
     */
    public void setCompareContent(final String pContent)
    {
        if (pContent==null)
        {
            throw new IllegalArgumentException("compare content must not be null");
        }
        mContent= pContent;
        checkStateChange();
    }

    /**
     * Updates the compare content from the current value of the document.
     */
    public void updateCompareFromDocument()
    {
        //noinspection EmptyCatchBlock
        try
        {
            mContent= mDocument.getText( 0, mDocument.getLength());
        }
        catch (BadLocationException ignored) {}
        checkStateChange();
    }

    /**
     * Check the document state.
     * @return true of our compare content matches the Document
     */
    protected boolean getInternalState()
    {
        String documentContent= null;

        //noinspection EmptyCatchBlock
        try
        {
            documentContent= mDocument.getText(0, mDocument.getLength());
        }
        catch (BadLocationException ignored) {}

        return mContent.equals(documentContent);
    }

    /**
     * Set the source of the state as the reason for a change.
     */
    protected void setReason()
    {
        mReason= mDocument;
    }

    /**
     * Gives notification that there was an insert into the document.  The
     * range given by the DocumentEvent bounds the freshly inserted region.
     *
     * @param pEvent the document event
     */
    public void insertUpdate(final DocumentEvent pEvent)
    {
        checkStateChange();
    }

    /**
     * Gives notification that a portion of the document has been
     * removed.  The range is given in terms of what the view last
     * saw (that is, before updating sticky positions).
     *
     * @param pEvent the document event
     */
    public void removeUpdate(final DocumentEvent pEvent)
    {
        checkStateChange();
    }

    /**
     * Gives notification that an attribute or set of attributes changed.
     *
     * @param pEvent the document event
     */
    public void changedUpdate(final DocumentEvent pEvent)
    {
        checkStateChange();
    }
}