net.hasor.dataql.domain.compiler.CompilerStack Maven / Gradle / Ivy

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/*
 * Copyright 2008-2009 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 net.hasor.dataql.domain.compiler;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
/**
 * 编译器用到的栈结构。
 * @author 赵永春([email protected])
 * @version : 2017-03-23
 */
public class CompilerStack {
    private Stack> dataStack = new Stack>();
    public CompilerStack() {
        this.dataStack.push(new ArrayList());
    }
    //
    public void newFrame() {
        this.dataStack.push(new ArrayList());
    }
    public void dropFrame() {
        this.dataStack.pop();
    }
    //
    /** 当前栈中是否存在该元素，如果存在返回位置 */
    public int containsWithCurrent(String target) {
        if (this.dataStack.isEmpty()) {
            return -1;
        } else {
            return this.dataStack.peek().indexOf(target);
        }
    }
    //
    /** 当前栈中是否存在该元素，如果存在返回位置 */
    public ContainsIndex containsWithTree(String target) {
        ContainsIndex index = new ContainsIndex();
        index.depth = -1; // <-无效值
        index.index = -1; // <-无效值
        //
        int stackSize = this.dataStack.size();
        for (int i = 0; i < this.dataStack.size(); i++) {
            index.current = i == 0;
            index.depth = stackSize - i - 1;
            List stringList = this.dataStack.get(index.depth);
            int indexOf = stringList.indexOf(target);
            if (indexOf >= 0) {
                index.index = indexOf;
                return index;
            }
        }
        //
        index.depth = 0;
        return index;
    }
    /** 将 name 压入栈，并返回在栈中的位置 */
    public int push(String target) {
        List nameStack = this.dataStack.peek();
        nameStack.add(target);
        return nameStack.indexOf(target);
    }
    //
    /** 当前深度 */
    public int getDepth() {
        return this.dataStack.size() - 1;
    }
    //
    public static class ContainsIndex {
        public int     depth   = 0;
        public int     index   = 0;
        public boolean current = false;
        //
        public boolean isValid() {
            return this.depth >= 0 && this.index >= 0;
        }
    }
}