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package com.datastax.data.dataset;

import com.datastax.data.dataset.event.DataTableEventAdapter;
import com.datastax.data.dataset.event.RowChangeEvent;
import com.datastax.data.dataset.event.TableChangeEvent;
import net.sf.jga.fn.EvaluationException;
import net.sf.jga.fn.Generator;
import net.sf.jga.fn.adaptor.Constant;
import net.sf.jga.parser.GeneratorRef;
import net.sf.jga.parser.ParseException;
import net.sf.jga.parser.UncheckedParseException;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.HashSet;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;


public class DataValue {
    
    
    protected static final String DEFAULT_NAME_PREFIX = "DataValue";
    
    
    private static final NameGenerator NAMEGEN = new NameGenerator(DEFAULT_NAME_PREFIX);
    
    
    private static final Logger LOG = Logger.getLogger(DataValue.class.getName());

    
    
    private PropertyChangeSupport pcs = new PropertyChangeSupport(this);

    
    private DataSet dataSet;
    
    
    private String name;
   
    
    private String expression;
    private Generator exprImpl;

    
    private Class type = Void.TYPE;
    
    
    public DataValue(DataSet ds) {
        assert ds != null;
        this.dataSet = ds;
        name = NAMEGEN.generateName(this);
    }
    
    
    public DataValue(DataSet ds, String name) {
        this(ds);
        if (name != null) {
            setName(name);
        }
    }
    
    
    public void setName(String name) {
        if (this.name != name) {
            assert DataSetUtils.isValidName(name);
            String oldName = this.name;
            this.name = name;
            pcs.firePropertyChange("name", oldName, name);
        }
    }

    
    public String getName() {
        return name;
    }

    
    public DataSet getDataSet() {
        return dataSet;
    }
    
    
    void removeFromDataSet() {
        dataSet = null;
        if (exprImpl != null) {
            Parser.unregister(exprImpl, listener, sources);
        }
    }
    
    
    public String getExpression() {
        return expression;
    }
    
    
    public void setExpression(String expression) {
        if (expression == null) {
            expression = "";
        }
    
        if ( !(expression.equals(this.expression))) {
            if (exprImpl != null) {
                Parser.unregister(exprImpl, listener, sources);
                exprImpl = null;
            }
            
            String oldExpression = this.expression;
            this.expression = expression;
            pcs.firePropertyChange("expression", oldExpression, expression);
        }
    }
    

    
    

    
    
    public Object getValue() {
        assert dataSet != null;
        if (exprImpl == null) {
            parseExpression();
        }
   
        
        try {
            return exprImpl == null ? null : exprImpl.gen();
        } catch (EvaluationException e) {
            LOG.log(Level.WARNING, "Cannot evaluate \""+expression+"\": returning null. {1}",
                    new Object[]{expression, e.getMessage()});
            return null;
        }
    }


    
    public Class getType() {
        if (exprImpl == null) {
            parseExpression();
        }
   
        return type;
    }

    
    private void setType(Class type) {
        if (type == null) {
            String msg = "A DataValue's type may not be null";
            throw new IllegalArgumentException(msg);
        }
        
        if (this.type != type) {
            Class oldType = this.type;
            this.type = type;
            pcs.firePropertyChange("type", oldType, type);
        }
    }


    public String toString() {
        return "Value " +getName()+" == " +getExpression();
    }

    
    Parser getParser() {
        return dataSet.getParser();
    }

    
    
    
    
    
    private boolean isParsing = false;
    
    private void parseExpression() {
        if (exprImpl != null)
            return;
        
        if (expression == null || expression.equals("")) {
            exprImpl = new Constant