org.drools.ide.common.server.util.DataEnumLoader Maven / Gradle / Ivy

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/**
 * Copyright 2010 JBoss Inc
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.drools.ide.common.server.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

import org.mvel2.MVEL;

/**
 * Use mvel to load up map/list of valid items for fields - used by the Guided rule editor.
 */
public class DataEnumLoader {

	private final List errors;
	private final Map data;

	/**
	 * This is the source of the asset, which is an MVEL map (minus the outer "[") of course.
	 */
	public DataEnumLoader(String mvelSource) {
		errors = new ArrayList();
		this.data = loadEnum(mvelSource);
	}

	private Map loadEnum(String mvelSource) {

        if (mvelSource == null || (mvelSource.trim().equals( "" ))) {
            return Collections.emptyMap();
        }
        if (mvelSource.startsWith("=")) {
        	mvelSource = mvelSource.substring(1);
        } else {
        	mvelSource = "[ " + addCommasForNewLines(mvelSource) + " ]";
        }
		final Object mvelData;
		try {
			mvelData = MVEL.eval(mvelSource, new HashMap());
		} catch (RuntimeException e) {
			addError("Unable to load enumeration data.");
			addError(e.getMessage());
			addError("Error type: " + e.getClass().getName());
			return Collections.emptyMap();
		}
		if (!(mvelData instanceof Map)) {
			addError("The expression is not a map, it is a " + mvelData.getClass().getName());
			return Collections.emptyMap();
		}
		Map map = (Map) mvelData;
        Map newMap = new HashMap();
		for (Map.Entry entry: map.entrySet()) {
			String key = entry.getKey();
			Object list = entry.getValue();
			if (!(list instanceof List || list instanceof String)) {
				if (list == null) {
					addError("The item with " + key + " is null.");
				} else {
					addError("The item with " + key + " is not a list or a string, it is a " + list.getClass().getName());
				}
				return Collections.emptyMap();
			} else if (list instanceof String) {
				newMap.put(key, new String[] {(String)list});
			} else {
				List items = (List) list;
				String[] newItems = new String[items.size()];
				for (int i = 0; i < items.size(); i++) {
					Object listItem = items.get(i);
					if (!(listItem instanceof String)) {
						newItems[i] = listItem.toString();
					} else {
						newItems[i] = (String) listItem;
					}
				}
				newMap.put(key, newItems);
			}
		}
		return newMap;
	}

	public static String addCommasForNewLines(String mvelSource) {
        StringTokenizer st = new StringTokenizer(mvelSource, "\r\n");
        StringBuilder buf = new StringBuilder();
        while(st.hasMoreTokens()) {
            String line = st.nextToken().trim();
            if (st.hasMoreTokens() && line.endsWith( "," )) {
                buf.append( line );
            } else {
                buf.append( line );
                if (st.hasMoreTokens()) {
                    buf.append( "," );
                }
            }
            if (st.hasMoreTokens()) {
                buf.append( "\n" );
            }
        }
        return buf.toString();
    }

    private void addError(String string) {
		this.errors.add(string);
	}

	/**
	 * Return a list of any errors found.
	 */
	public List getErrors() {
		return this.errors;
	}

    public boolean hasErrors() {
        return this.errors.size() > 0;
    }

	/**
	 * Return the map of Fact.field to List (of Strings).
	 */
	public Map getData() {
		return this.data;
	}

}