Application: gvSIG desktop

package org.gvsig.expressionevaluator.spi;

import java.util.ArrayList;

import java.util.Collection;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import org.gvsig.expressionevaluator.Code;

import org.gvsig.expressionevaluator.Expression;

import org.gvsig.expressionevaluator.ExpressionEvaluator;

import org.gvsig.expressionevaluator.ExpressionEvaluatorLocator;

import org.gvsig.expressionevaluator.ExpressionEvaluatorManager;

import org.gvsig.expressionevaluator.Function;

import org.gvsig.expressionevaluator.SupportToExpression;

import org.gvsig.expressionevaluator.SupportToSymbolTable;

import org.gvsig.expressionevaluator.SymbolTable;

import org.gvsig.tools.ToolsLocator;

import org.gvsig.tools.dynobject.DynStruct;

import org.gvsig.tools.evaluator.AbstractEvaluator;

import org.gvsig.tools.evaluator.Evaluator;

import org.gvsig.tools.evaluator.EvaluatorData;

import org.gvsig.tools.evaluator.EvaluatorException;

import org.gvsig.tools.evaluator.EvaluatorFieldsInfo;

import org.gvsig.tools.exception.BaseException;

import org.gvsig.tools.lang.Cloneable;

import org.gvsig.tools.persistence.PersistenceManager;

import org.gvsig.tools.persistence.PersistentState;

import org.gvsig.tools.persistence.exception.PersistenceException;

import org.gvsig.tools.util.ListBuilder;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

@SuppressWarnings("UseSpecificCatch")

public class BaseExpressionEvaluator 

        extends AbstractEvaluator 

        implements ExpressionEvaluator, Cloneable, SupportToExpression, SupportToSymbolTable

    {

    private static final Logger LOGGER = LoggerFactory.getLogger(BaseExpressionEvaluator.class);

    private static class DescriptionAdapter implements Description {

        Function function;

        public DescriptionAdapter(Function function) {

            this.function = function;

        }

        @Override

        public String getName() {

            return this.function.name();

        }

        @Override

        public String getDescription() {

            return this.function.description();

        }

        @Override

        public String getTemplate() {

            return this.function.template();

        }

        @Override

        public int getDataTypeCategories() {

            switch (this.function.group()) {

                case Function.GROUP_STRING:

                    return Description.DATATYPE_CATEGORY_STRING;

                case Function.GROUP_BOOLEAN:

                    return Description.DATATYPE_CATEGORY_BOOLEAN;

                case Function.GROUP_DATETIME:

                    return Description.DATATYPE_CATEGORY_DATETIME;

                case Function.GROUP_NUMERIC:

                    return Description.DATATYPE_CATEGORY_NUMBER;

                case Function.GROUP_OGC:

                    return Description.DATATYPE_CATEGORY_ALL;

                default:

                    return Description.DATATYPE_CATEGORY_ALL;

            }

        }

    }

    private static class DataSymbolTable extends AbstractSymbolTable {

        EvaluatorData data;

        public DataSymbolTable() {

            super();

        }

        public void setData(EvaluatorData data) {

            this.data = data;

        }

        @Override

        public boolean exists(String name) {

            return data.hasDataValue(name);

        }

        @Override

        public Object value(String name) {

            return data.getDataValue(name);

        }

        @Override

        public Collection<String> localvariables() {

            List<String> names = ListBuilder.create(data.getDataNames());

            return names;

        }

        @Override

        public DataSymbolTable clone() throws CloneNotSupportedException {

            SymbolTable other = super.clone();

            return (DataSymbolTable) other;

        }

    }

    private DataSymbolTable dataSymbolTable;

    private SymbolTable symbolTable;

    private Expression expression;

    private Description[] availableOperators;

    private Description[] availableFunctions;

    public BaseExpressionEvaluator(String source) {

        ExpressionEvaluatorManager manager = ExpressionEvaluatorLocator.getManager();

        this.symbolTable = manager.createSymbolTable();

        this.dataSymbolTable = new DataSymbolTable();

        this.symbolTable.addSymbolTable(this.dataSymbolTable);

        this.expression = manager.createExpression();

        this.expression.setPhrase(source);

    }

    public BaseExpressionEvaluator(Expression expression) {

        ExpressionEvaluatorManager manager = ExpressionEvaluatorLocator.getManager();

        this.symbolTable = manager.createSymbolTable();

        this.dataSymbolTable = new DataSymbolTable();

        this.symbolTable.addSymbolTable(this.dataSymbolTable);

        this.expression = expression;

    }

    @Override

    public String getName() {

        return "Genereric expression";

    }

    @Override

    public String getDescription() {

        return this.expression.getPhrase();

    }

    @Override

    public String getSQL() {

        return this.expression.getPhrase();

    }

    @Override

    public Expression toExpression() {

        return expression;

    }

    @Override

    public SymbolTable toSymbolTable() {

        return this.symbolTable;

    }

    @Override

    public Object evaluate(EvaluatorData data) throws EvaluatorException {

        this.dataSymbolTable.setData(data);

        Object v = this.expression.execute(this.symbolTable);

        return v;

    }

    @Override

    public EvaluatorFieldsInfo getFieldsInfo() {

        final Set<String> names = new HashSet<>();

        try {

            this.expression.getCode().accept((Object code) -> {

              if (code instanceof Code.Identifier) {

                Code.Identifier identifier = (Code.Identifier) code;

                names.add(identifier.name());

              }

            });

            EvaluatorFieldsInfo info = new EvaluatorFieldsInfo();

            for (String name : names) {

                info.addFieldValue(name);

            }

            return info;

        } catch (BaseException ex) {

            throw new RuntimeException("Can't calculate fields information.", ex);

        }

    }

    @Override

    public Description[] getAvailableOperators() {

        if (availableOperators == null) {

            List<Description> l = new ArrayList<>();

            for (Function function : toSymbolTable()) {

                if (function.isOperator()) {

                    l.add(new DescriptionAdapter(function));

                }

            }

            this.availableOperators = l.toArray(new Description[l.size()]);

        }

        return availableOperators;

    }

    @Override

    public Description[] getAvailableFunctions() {

        if (availableFunctions == null) {

            List<Description> l = new ArrayList<>();

            for (Function function : toSymbolTable()) {

                if (!function.isOperator()) {

                    l.add(new DescriptionAdapter(function));

                }

            }

            this.availableFunctions = l.toArray(new Description[l.size()]);

        }

        return availableFunctions;

    }

    @Override

    public Evaluator clone() throws CloneNotSupportedException {

        BaseExpressionEvaluator other = (BaseExpressionEvaluator) super.clone();

        other.expression = this.expression.clone();

        other.availableFunctions = null;

        other.availableOperators = null;

        if (this.dataSymbolTable != null) {

            other.dataSymbolTable = this.dataSymbolTable.clone();

        }

        if (this.symbolTable != null) {

            other.symbolTable = this.symbolTable.clone();

        }

        return other;

    }

    @Override

    public void saveToState(PersistentState state) throws PersistenceException {

        state.set("expression", expression);

    }

    @Override

    public void loadFromState(PersistentState state) throws PersistenceException {

        expression = (Expression) state.get("expression");

        availableFunctions = null;

        availableOperators = null;

        ExpressionEvaluatorManager manager = ExpressionEvaluatorLocator.getManager();

        this.symbolTable = manager.createSymbolTable();

        this.dataSymbolTable = new DataSymbolTable();

        this.symbolTable.addSymbolTable(this.dataSymbolTable);

    }

    public static void registerPersistence() {

        PersistenceManager manager = ToolsLocator.getPersistenceManager();

        if (manager.getDefinition("DefaultExpressionEvaluator") == null) {

            DynStruct definition = manager.addDefinition(BaseExpressionEvaluator.class,

                    "DefaultExpressionEvaluator", "DefaultExpressionEvaluator persistence definition", null, null);

            definition.addDynFieldObject("expression").setClassOfValue(Expression.class).setMandatory(false);

        }

    }

}