/*
 * Copyright 2003-2007 the original author or authors.
 *
 * 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.codehaus.groovy.ast;

import org.codehaus.groovy.GroovyBugError;
import org.codehaus.groovy.util.ListHashMap;

/**
 * Base class for any AST node. This class supports basic information used in all
 * nodes of the AST<ul>
 * <li> line and column number information. Usually a node represents a certain
 * area in a text file determined by a starting position and an ending position.
 * For nodes that do not represent this, this information will be -1. A node can
 * also be configured in its line/col information using another node through 
 * setSourcePosition(otherNode).</li>
 * <li> every node can store meta data. A phase operation or transform can use 
 * this to transport arbitrary information to another phase operation or 
 * transform. The only requirement is that the other phase operation or transform
 * runs after the part storing the information. If the information transport is 
 * done it is strongly recommended to remove that meta data.</li> 
 * </ul>
 * <li> a text representation of this node trough getText(). This was in the 
 * past used for assertion messages. Since the usage of power asserts this 
 * method will not be called for this purpose anymore and might be removed in
 * future versions of Groovy</li>
 * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
 * @author <a href="maito:blackdrag@gmx.org>Jochen "blackdrag" Theodorou</a>
 * @version $Revision$
 */
public class ASTNode {

    private int lineNumber = -1;
    private int columnNumber = -1;
    private int lastLineNumber = -1;
    private int lastColumnNumber = -1;
    private ListHashMap metaDataMap = new ListHashMap(); 

    public void visit(GroovyCodeVisitor visitor) {
        throw new RuntimeException("No visit() method implemented for class: " + getClass().getName());
    }

    public String getText() {
        return "<not implemented yet for class: " + getClass().getName() + ">";
    }

    public int getLineNumber() {
        return lineNumber;
    }

    public void setLineNumber(int lineNumber) {
        this.lineNumber = lineNumber;
    }

    public int getColumnNumber() {
        return columnNumber;
    }

    public void setColumnNumber(int columnNumber) {
        this.columnNumber = columnNumber;
    }

    public int getLastLineNumber() {
        return lastLineNumber;
    }

    public void setLastLineNumber(int lastLineNumber) {
        this.lastLineNumber = lastLineNumber;
    }

    public int getLastColumnNumber() {
        return lastColumnNumber;
    }

    public void setLastColumnNumber(int lastColumnNumber) {
        this.lastColumnNumber = lastColumnNumber;
    }
    
    /**
     * Sets the source position using another ASTNode.
     * The sourcePosition consists of a line/column pair for
     * the start and a line/column pair for the end of the
     * expression or statement 
     * 
     * @param node - the node used to configure the position information
     */
    public void setSourcePosition(ASTNode node) {
        this.columnNumber = node.getColumnNumber();
        this.lastLineNumber = node.getLastLineNumber();
        this.lastColumnNumber = node.getLastColumnNumber();
        this.lineNumber = node.getLineNumber();
    }
    
    /**
     * Gets the node meta data. 
     * 
     * @param key - the meta data key
     * @return the node meta data value for this key
     */
    public Object getNodeMetaData(Object key) {
        return metaDataMap.get(key);
    }
    
    /**
     * Copies all node meta data from one node to the other
     * @param other - the other node
     */
    public void copyNodeMetaData(ASTNode other) {
        metaDataMap.putAll(other.metaDataMap);
    }
    
    /**
     * Sets the node meta data. 
     * 
     * @param key - the meta data key
     * @param value - the meta data value
     * @throws GroovyBugError if key is null or there is already meta 
     *                        data under that key
     */
    public void setNodeMetaData(Object key, Object value) {
        if (key==null) throw new GroovyBugError("Tried to set meta data with null key on "+this+".");
        Object old = metaDataMap.put(key,value);
        if (old!=null) throw new GroovyBugError("Tried to overwrite existing meta data "+this+".");
    }
    
    /**
     * Removes a node meta data entry.
     * 
     * @param key - the meta data key
     * @throws GroovyBugError if the key is null
     */
    public void removeNodeMetaData(Object key) {
        if (key==null) throw new GroovyBugError("Tried to remove meta data with null key "+this+".");
        metaDataMap.remove(key);
        if (metaDataMap.size()==0) metaDataMap=null;
    }
}