org.structr.core.parser.ArrayExpression.java Source code

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Here is the source code for org.structr.core.parser.ArrayExpression.java

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/**
 * Copyright (C) 2010-2016 Structr GmbH
 *
 * This file is part of Structr <http://structr.org>.
 *
 * Structr 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.
 *
 * Structr 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 Structr.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.structr.core.parser;

import java.util.Collection;
import org.apache.commons.collections.CollectionUtils;
import org.structr.common.error.FrameworkException;
import org.structr.core.GraphObject;
import org.structr.schema.action.ActionContext;

/**
 *
 *
 */

public class ArrayExpression extends Expression {

    @Override
    public String toString() {

        final StringBuilder buf = new StringBuilder();

        buf.append("[");

        for (final Expression expr : expressions) {
            buf.append(expr.toString());
        }
        buf.append("]");

        return buf.toString();
    }

    @Override
    public void add(final Expression expression) throws FrameworkException {

        if (!expressions.isEmpty()) {
            throw new FrameworkException(422, "Invalid expression: expected ], found another expression.");
        }

        super.add(expression);
    }

    @Override
    public Object evaluate(final ActionContext ctx, final GraphObject entity) throws FrameworkException {

        switch (expressions.size()) {

        case 0:
            throw new FrameworkException(422, "Invalid expression: expected expression, found ].");

        case 1:
            final Object value = expressions.get(0).evaluate(ctx, entity);
            if (value instanceof Number) {

                return ((Number) value).intValue();
            }
        }

        return null;
    }

    @Override
    public Object transform(final ActionContext ctx, final GraphObject entity, final Object value)
            throws FrameworkException {

        if (value == null) {
            return null;
        }

        final Integer index = (Integer) evaluate(ctx, entity);
        if (index != null) {

            if (value instanceof Collection || value.getClass().isArray()) {

                try {

                    // silently ignore array index errors
                    return CollectionUtils.get(value, index);

                } catch (ArrayIndexOutOfBoundsException ignore) {
                }

            } else {

                throw new FrameworkException(422,
                        "Invalid expression: expected collection, found " + value.getClass().getSimpleName() + ".");
            }

        } else {

            throw new FrameworkException(422, "Invalid expression: invalid array index: null.");
        }

        return null;
    }
}