/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 2008 jOpenDocument, by ILM Informatique. All rights reserved.
 * 
 * The contents of this file are subject to the terms of the GNU
 * General Public License Version 3 only ("GPL").  
 * You may not use this file except in compliance with the License. 
 * You can obtain a copy of the License at http://www.gnu.org/licenses/gpl-3.0.html
 * See the License for the specific language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each file.
 * 
 */

package org.jopendocument.dom.template.engine;

import org.jopendocument.dom.template.TemplateException;

import java.util.Map;

public abstract class DataModel {

    public abstract void put(String name, Object value);

    /**
     * Copies all of the mappings from the specified map to this. This implementation simply calls
     * {@link #put(String,Object) put(k, v)} once for each entry in the specified map.
     * 
     * @param toMerge mappings to be stored.
     */
    public void putAll(Map<? extends String, ?> toMerge) {
        for (final Map.Entry<? extends String, ?> e : toMerge.entrySet()) {
            this.put(e.getKey(), e.getValue());
        }
    }

    protected abstract Object _eval(String expression) throws Exception;

    public final Object eval(String expression) throws TemplateException {
        try {
            return this._eval(expression);
        } catch (Throwable t) {
            throw new TemplateException("invalid expression: \"" + expression + "\"", t);
        }
    }

    /**
     * Copy this engine and especially its bindings.
     * 
     * @return an independant copy of this.
     */
    public abstract DataModel copy();
}
