com.chadekin.jadys.commons.expression.SqlExpressionHandler.java Source code

Introduction

Here is the source code for com.chadekin.jadys.commons.expression.SqlExpressionHandler.java

Source

/**
 *                     GNU General Public License (GPL)
 *                        version 3.0, 29 June 2007
 *
 * 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 3 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, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 *
 * Copyright (C) 2017 Marc Mamiah.
 * License GPLv3+: GNU GPL version 3
 */
package com.chadekin.jadys.commons.expression;

import java.util.EnumSet;
import java.util.Set;
import java.util.TreeSet;
import java.util.stream.Collectors;
import com.chadekin.jadys.commons.enums.ConditionType;
import com.chadekin.jadys.commons.enums.JadysSqlOperation;
import com.chadekin.jadys.model.SqlExpressionItem;
import org.apache.commons.lang.StringUtils;

/**
 * SqlExpressionHandler
 */
public interface SqlExpressionHandler<T> {

    // Collecting SQL Logical Expression like 'AND', 'OR'
    public static final Set<JadysSqlOperation> LOGICAL_OPERATORS = EnumSet.allOf(JadysSqlOperation.class).stream()
            .filter(operator -> operator.getType() == ConditionType.LOGICAL).collect(Collectors.toSet());

    /**
     * Add an argument to the expression to be included to the actual builder, after verifying it is a valid expression
     * @param arg
     * @return
     */
    public default T addArgument(Object arg) {
        SqlExpressionItem expressionItem = getSqlExpressionItem();
        if (expressionItem == null) {
            setSqlExpressionItem(new SqlExpressionItem());
        }

        if (LOGICAL_OPERATORS.contains(arg)) {
            getSqlExpressionItem().appendLogicalOperator((JadysSqlOperation) arg);
        } else if (arg instanceof JadysSqlOperation) {
            JadysSqlOperation operator = (JadysSqlOperation) arg;
            TreeSet logicalOperators = getSqlExpressionItem().getLogicalOperator();
            if (!logicalOperators.isEmpty() && logicalOperators.last() == JadysSqlOperation.NOT) {
                operator = operator.getOpposite();
                getSqlExpressionItem().getLogicalOperator().remove(JadysSqlOperation.NOT);
            }
            getSqlExpressionItem().setOperator(operator);
        } else if (getSqlExpressionItem().getParam() == null) {
            String parameter = arg == null ? StringUtils.EMPTY : arg.toString();
            getSqlExpressionItem().setParam(parameter);
        } else if (arg == null) {
            setSqlExpressionItem(null);
        } else if (getSqlExpressionItem().getValue() == null) {
            getSqlExpressionItem().setValue(arg);
        }

        if (getSqlExpressionItem() != null && getSqlExpressionItem().isReady()) {
            finalizeExpression();
            setSqlExpressionItem(null);
        }
        return (T) this;
    }

    public void setSqlExpressionItem(SqlExpressionItem expressionItem);

    public SqlExpressionItem getSqlExpressionItem();

    /**
     * Add the resulting expression to the actual builder result
     */
    public void finalizeExpression();

}