XtendFlow/FlowDesignInXtend/src/de/grammarcraft/xtend/annotatedflow/Collector.xtend at Article08FlowDesignInXtend · kuniss/XtendFlow · GitHub

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package de.grammarcraft.xtend.annotatedflow

import de.grammarcraft.xtend.flow.annotations.FunctionUnit
import java.util.List
import java.util.ArrayList
import de.grammarcraft.xtend.flow.annotations.InputPort
import de.grammarcraft.xtend.flow.annotations.OutputPort

@FunctionUnit(
    inputPorts = #[
        @InputPort(name="lower", type=String),
        @InputPort(name="upper", type=String)
    ],
    outputPorts = #[
        @OutputPort(name="output", type=String),
        @OutputPort(name="error", type=String)
    ]
)
class Collector {

    new(String separator) {
        this.separator = separator;
    }

    override processLower(String msg) {
        if (accumulation.length >= 2)
            error.forward(this + ' got more than two input messages; not allowed')
        accumulateInput(msg)
    }

    override processUpper(String msg) {
        if (accumulation.length >= 2)
            error.forward(this + ' got more than two input messages; not allowed')
        accumulateInput(msg)
    }

    var String separator
    val List<String> accumulation = new ArrayList

    // This method implements the semantic of the function unit
    private def accumulateInput(String msg) {
        accumulation.add(msg)
        if (accumulation.length == 2) output.forward(accumulation.join(separator))
    }


}