io.datakernel.codegen.ExpressionToString.java Source code

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Here is the source code for io.datakernel.codegen.ExpressionToString.java

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/*
 * Copyright (C) 2015 SoftIndex LLC.
 *
 * 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 io.datakernel.codegen;

import org.objectweb.asm.Label;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.GeneratorAdapter;
import org.objectweb.asm.commons.Method;

import java.util.LinkedHashMap;
import java.util.Map;

import static io.datakernel.codegen.Utils.isPrimitiveType;
import static io.datakernel.codegen.Utils.wrap;
import static org.objectweb.asm.Type.getType;
import static org.objectweb.asm.commons.Method.getMethod;

/**
 * Defines methods which allow to create a string
 */
@SuppressWarnings("PointlessArithmeticExpression")
public final class ExpressionToString implements Expression {
    private String begin = "{";
    private String end = "}";
    private String separator = " ";
    private final Map<Object, Expression> arguments = new LinkedHashMap<>();

    ExpressionToString(Map<String, Expression> arguments) {
        this.arguments.putAll(arguments);
    }

    ExpressionToString() {
    }

    public ExpressionToString add(String label, Expression expression) {
        this.arguments.put(label, expression);
        return this;
    }

    public ExpressionToString add(Expression expression) {
        this.arguments.put(arguments.size() + 1, expression);
        return this;
    }

    public ExpressionToString separator(String separator) {
        this.separator = separator;
        return this;
    }

    public ExpressionToString quotes(String begin, String end) {
        this.begin = begin;
        this.end = end;
        return this;
    }

    public ExpressionToString quotes(String begin, String end, String separator) {
        this.begin = begin;
        this.end = end;
        this.separator = separator;
        return this;
    }

    @Override
    public Type type(Context ctx) {
        return getType(String.class);
    }

    @Override
    public Type load(Context ctx) {
        final GeneratorAdapter g = ctx.getGeneratorAdapter();

        g.newInstance(getType(StringBuilder.class));
        g.dup();
        g.invokeConstructor(getType(StringBuilder.class), getMethod("void <init> ()"));

        boolean first = true;

        for (Object key : arguments.keySet()) {
            String str = first ? begin : separator;
            first = false;
            if (key instanceof String) {
                str += key;
            }
            if (!str.isEmpty()) {
                g.dup();
                g.push(str);
                g.invokeVirtual(getType(StringBuilder.class), getMethod("StringBuilder append(String)"));
                g.pop();
            }

            g.dup();
            final Expression expression = arguments.get(key);
            final Type type = expression.load(ctx);
            if (isPrimitiveType(type)) {
                g.invokeStatic(wrap(type), new Method("toString", getType(String.class), new Type[] { type }));
            } else {
                final Label nullLabel = new Label();
                final Label afterToString = new Label();
                g.dup();
                g.ifNull(nullLabel);
                g.invokeVirtual(type, getMethod("String toString()"));
                g.goTo(afterToString);
                g.mark(nullLabel);
                g.pop();
                g.push(("null"));
                g.mark(afterToString);
            }
            g.invokeVirtual(getType(StringBuilder.class), getMethod("StringBuilder append(String)"));
            g.pop();
        }

        if (!end.isEmpty()) {
            g.dup();
            g.push(end);
            g.invokeVirtual(getType(StringBuilder.class), getMethod("StringBuilder append(String)"));
            g.pop();
        }

        g.invokeVirtual(getType(StringBuilder.class), getMethod("String toString()"));
        return type(ctx);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o)
            return true;
        if (o == null || getClass() != o.getClass())
            return false;

        ExpressionToString that = (ExpressionToString) o;

        if (arguments != null ? !arguments.equals(that.arguments) : that.arguments != null)
            return false;

        return true;
    }

    @Override
    public int hashCode() {
        return (arguments != null ? arguments.hashCode() : 0);
    }
}