jetbrains.exodus.query.BinaryOperator.java Source code

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Here is the source code for jetbrains.exodus.query.BinaryOperator.java

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/**
 * Copyright 2010 - 2015 JetBrains s.r.o.
 *
 * 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 jetbrains.exodus.query;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jetbrains.annotations.NotNull;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public abstract class BinaryOperator extends NodeBase {

    private static Log log = LogFactory.getLog(BinaryOperator.class);
    private static boolean isWarnEnabled = log.isWarnEnabled();
    private static final int MAXIMUM_LEGAL_DEPTH = 200;
    private static final int LARGE_DEPTH_LOGGING_FREQ = 10000;
    private static volatile long lastLoggedMillis = 0;

    private NodeBase left;
    private NodeBase right;
    private List<NodeBase> children;
    private final int depth;

    BinaryOperator(@NotNull final NodeBase left, @NotNull final NodeBase right) {
        this.left = getUnderRoot(left);
        this.right = getUnderRoot(right);
        this.left.setParent(this);
        this.right.setParent(this);
        final int leftDepth = left instanceof BinaryOperator ? ((BinaryOperator) left).depth : 1;
        final int rightDepth = right instanceof BinaryOperator ? ((BinaryOperator) right).depth : 1;
        depth = leftDepth < rightDepth ? rightDepth + 1 : leftDepth + 1;
        if (isWarnEnabled && depth >= MAXIMUM_LEGAL_DEPTH && (depth % MAXIMUM_LEGAL_DEPTH) == 0) {
            final long millis = System.currentTimeMillis();
            if (millis - lastLoggedMillis > LARGE_DEPTH_LOGGING_FREQ) {
                lastLoggedMillis = millis;
                log.warn("Binary operator of too great depth", new Throwable());
            }
        }
    }

    public NodeBase getLeft() {
        return left;
    }

    public NodeBase getRight() {
        return right;
    }

    @Override
    public NodeBase replaceChild(final NodeBase child, final NodeBase newChild) {
        if (child == left) {
            setLeft(newChild);
        } else if (child == right) {
            setRight(newChild);
        } else {
            throw new RuntimeException(getClass() + ": can't replace not own child");
        }
        newChild.setParent(this);
        return child;
    }

    @Override
    public Collection<NodeBase> getChildren() {
        if (children == null) {
            final ArrayList<NodeBase> result = new ArrayList<>(2);
            result.add(left);
            result.add(right);
            children = result;
        }
        return children;
    }

    @Override
    protected boolean matchChildren(NodeBase node, NodeBase.MatchContext ctx) {
        final BinaryOperator _node = (BinaryOperator) node;
        if (!(left.match(_node.left, ctx))) {
            return false;
        }
        return right.match(_node.right, ctx);
    }

    void setLeft(NodeBase left) {
        this.left = left;
        if (children != null) {
            children.set(0, left);
        }
    }

    void setRight(NodeBase right) {
        this.right = right;
        if (children != null) {
            children.set(1, right);
        }
    }

    /*package*/
    @Override
    public StringBuilder getHandle(StringBuilder sb) {
        super.getHandle(sb).append('{');
        sb = left.getHandle(sb).append(',');
        return right.getHandle(sb).append('}');
    }
}