/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
package com.espertech.esper.epl.expression.core;
import com.espertech.esper.epl.expression.visitor.ExprNodeVisitor;
import com.espertech.esper.epl.expression.visitor.ExprNodeVisitorWithParent;
import com.espertech.esper.util.CollectionUtil;
import java.io.StringWriter;
import java.util.Collection;
/**
* Superclass for filter nodes in a filter expression tree. Allow
* validation against stream event types and evaluation of events against filter tree.
*/
public abstract class ExprNodeBase implements ExprNode {
private static final long serialVersionUID = 0L;
private ExprNode[] childNodes;
/**
* Constructor creates a list of child nodes.
*/
public ExprNodeBase() {
childNodes = ExprNodeUtility.EMPTY_EXPR_ARRAY;
}
public abstract void toPrecedenceFreeEPL(StringWriter writer);
public void accept(ExprNodeVisitor visitor) {
if (visitor.isVisit(this)) {
visitor.visit(this);
for (ExprNode childNode : childNodes) {
childNode.accept(visitor);
}
}
}
public void accept(ExprNodeVisitorWithParent visitor) {
if (visitor.isVisit(this)) {
visitor.visit(this, null);
for (ExprNode childNode : childNodes) {
childNode.acceptChildnodes(visitor, this);
}
}
}
public void acceptChildnodes(ExprNodeVisitorWithParent visitor, ExprNode parent) {
if (visitor.isVisit(this)) {
visitor.visit(this, parent);
for (ExprNode childNode : childNodes) {
childNode.acceptChildnodes(visitor, this);
}
}
}
public final void addChildNode(ExprNode childNode) {
childNodes = (ExprNode[]) CollectionUtil.arrayExpandAddSingle(childNodes, childNode);
}
public final void addChildNodes(Collection<ExprNode> childNodeColl) {
childNodes = (ExprNode[]) CollectionUtil.arrayExpandAddElements(childNodes, childNodeColl);
}
public final ExprNode[] getChildNodes() {
return childNodes;
}
public void replaceUnlistedChildNode(ExprNode nodeToReplace, ExprNode newNode) {
// Override to replace child expression nodes that are chained or otherwise not listed as child nodes
}
public void addChildNodeToFront(ExprNode childNode) {
childNodes = (ExprNode[]) CollectionUtil.arrayExpandAddElements(new ExprNode[]{childNode}, childNodes);
}
public void setChildNodes(ExprNode... nodes) {
this.childNodes = nodes;
}
public void setChildNode(int index, ExprNode newNode) {
this.childNodes[index] = newNode;
}
public void toEPL(StringWriter writer, ExprPrecedenceEnum parentPrecedence) {
if (this.getPrecedence().getLevel() < parentPrecedence.getLevel()) {
writer.write("(");
toPrecedenceFreeEPL(writer);
writer.write(")");
} else {
toPrecedenceFreeEPL(writer);
}
}
}