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4 files changed, 353 insertions, 0 deletions

diff --git a/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelBuilder.java b/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelBuilder.java
new file mode 100644
index 00000000000..a0b1be20df6
--- /dev/null
+++ b/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelBuilder.java
@@ -0,0 +1,119 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.model.builder.xml;
+
+import com.yahoo.component.AbstractComponent;
+import com.yahoo.config.model.ConfigModel;
+import com.yahoo.config.model.ConfigModelContext;
+import com.yahoo.config.model.ConfigModelInstanceFactory;
+import com.yahoo.config.model.ConfigModelRepo;
+import com.yahoo.config.model.api.ConfigModelPlugin;
+import com.yahoo.config.model.deploy.DeployState;
+import com.yahoo.config.model.producer.AbstractConfigProducer;
+import org.w3c.dom.Element;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.List;
+
+/**
+ * Builds a config model using DOM parsers
+ *
+ * @author vegardh
+ * @since 5.1.10
+ */
+public abstract class ConfigModelBuilder<MODEL extends ConfigModel> extends AbstractComponent implements ConfigModelPlugin {
+
+    private Class<MODEL> configModelClass;
+
+    public ConfigModelBuilder(Class<MODEL> configModelClass) {
+        this.configModelClass = configModelClass;
+    }
+
+    /**
+     * Method that must return the XML elements this builder handles. Subclasses must implement this in order to
+     * get called when one of the elements have been encountered when parsing.
+     *
+     * @return A list of elements that this builder handles.
+     */
+    public abstract List<ConfigModelId> handlesElements();
+
+    /**
+     * Convenience hook called from {@link #build}. Implement this method to build a config model.
+     *
+     * @param spec The XML element that this builder should handle.
+     * @param modelContext A model context that contains the application package and other data needed by the
+     *                     config model constructor.
+     */
+    public abstract void doBuild(MODEL model, Element spec, ConfigModelContext modelContext);
+
+    /**
+     * Builds an instance of this component model.
+     * This calls instantiate(...), instance.setUp(...), doBuild(instance, ...).
+     *
+     * @param deployState a global deployment state used for this model.
+     * @param parent the root config producer this should be added to
+     * @param spec the XML element this is constructed from
+     */
+    public final MODEL build(DeployState deployState, ConfigModelRepo configModelRepo, AbstractConfigProducer parent, Element spec) {
+        ConfigModelContext context = ConfigModelContext.create(deployState, configModelRepo, parent, getIdString(spec));
+        return build(new DefaultModelInstanceFactory(), spec, context);
+    }
+
+    /**
+     * Builds an instance of this component model.
+     * This calls instantiate(...), instance.setUp(...), doBuild(instance, ...).
+     *
+     * @param factory A factory capable of creating models.
+     * @param spec the XML element this is constructed from
+     * @param context A context object containing various data used by builders.
+     */
+    public MODEL build(ConfigModelInstanceFactory<MODEL> factory, Element spec, ConfigModelContext context) {
+        MODEL model = factory.createModel(context);
+        doBuild(model, spec, context);
+        return model;
+    }
+
+    public Class<MODEL> getModelClass() {
+        return configModelClass;
+    }
+
+    private static String getIdString(Element spec) {
+        String idString = XmlHelper.getIdString(spec);
+        if (idString == null || idString.isEmpty()) {
+            idString = spec.getTagName();
+        }
+        return idString;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (!(other instanceof ConfigModelBuilder)) {
+            return false;
+        }
+        ConfigModelBuilder otherBuilder = (ConfigModelBuilder) other;
+        List<ConfigModelId> thisIds = this.handlesElements();
+        List<ConfigModelId> otherIds = otherBuilder.handlesElements();
+        if (thisIds.size() != otherIds.size()) {
+            return false;
+        }
+        for (int i = 0; i < thisIds.size(); i++) {
+            if (!thisIds.get(i).equals(otherIds.get(i))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+
+    private class DefaultModelInstanceFactory implements ConfigModelInstanceFactory<MODEL> {
+        @Override
+        public MODEL createModel(ConfigModelContext context) {
+            try {
+                Constructor<MODEL> constructor = configModelClass.getConstructor(ConfigModelContext.class);
+                return constructor.newInstance(context);
+            } catch (NoSuchMethodException | InvocationTargetException | InstantiationException | IllegalAccessException e) {
+                throw new RuntimeException("Error constructing model '" + configModelClass.getName() + "'", e);
+            }
+        }
+    }
+}
diff --git a/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelId.java b/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelId.java
new file mode 100644
index 00000000000..fca114757ec
--- /dev/null
+++ b/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelId.java
@@ -0,0 +1,94 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.model.builder.xml;
+
+import com.yahoo.component.Version;
+
+/**
+ * A {@link ConfigModelId} describes an element handled by a {@link ConfigModelBuilder}.
+ *
+ * @author lulf
+ * @since 5.1
+ */
+public class ConfigModelId implements Comparable<ConfigModelId> {
+
+    private final String name;
+    private final Version version;
+    private final String stringValue;
+
+    private ConfigModelId(String name, Version version) {
+        this.name = name;
+        this.version = version;
+        this.stringValue = toStringValue();
+    }
+
+    /**
+     * Create id with a name and version
+     * @param tagName Name of the id
+     * @param tagVersion Version of the id
+     * @return A ConfigModelId instance
+     */
+    public static ConfigModelId fromNameAndVersion(String tagName, String tagVersion) {
+        return new ConfigModelId(tagName, Version.fromString(tagVersion));
+    }
+
+    /**
+     * Create id with given name, using default version 1.
+     *
+     * @param tagName Name of the id
+     * @return A ConfigModelId instance
+     */
+    public static ConfigModelId fromName(String tagName) {
+        return new ConfigModelId(tagName, new Version(1));
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        if (!(object instanceof ConfigModelId)) return false;
+        ConfigModelId other = (ConfigModelId)object;
+        return this.name.equals(other.name) && this.version.equals(other.version);
+    }
+
+    @Override
+    public int compareTo(ConfigModelId other) {
+        if (other == this) return 0;
+        int cmp = this.name.compareTo(other.name);
+        if (cmp == 0) {
+            cmp = this.version.compareTo(other.version);
+        }
+        return cmp;
+    }
+
+    @Override
+    public String toString() {
+        return stringValue;
+    }
+
+    @Override
+    public int hashCode() {
+        return stringValue.hashCode();
+    }
+
+    /**
+     * Return the XML element name.
+     * @return the name of the config model
+     */
+    public String getName() {
+        return name;
+    }
+
+    /**
+     * Return the XML element version.
+     * @return the version of the config model
+     */
+    Version getVersion() {
+        return version;
+    }
+
+    private String toStringValue() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(name);
+        sb.append(".");
+        sb.append(version);
+        return sb.toString();
+    }
+}
diff --git a/config-model/src/main/java/com/yahoo/config/model/builder/xml/XmlHelper.java b/config-model/src/main/java/com/yahoo/config/model/builder/xml/XmlHelper.java
new file mode 100644
index 00000000000..924d888b0d0
--- /dev/null
+++ b/config-model/src/main/java/com/yahoo/config/model/builder/xml/XmlHelper.java
@@ -0,0 +1,135 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.model.builder.xml;
+
+import com.yahoo.component.ComponentId;
+import com.yahoo.component.ComponentSpecification;
+import com.yahoo.log.LogLevel;
+import com.yahoo.text.XML;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.xml.sax.InputSource;
+import org.xml.sax.SAXException;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import java.io.IOException;
+import java.io.Reader;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Optional;
+import java.util.logging.Logger;
+
+
+/**
+ * Static methods for helping dom building
+ *
+ * @author <a href="mailto:bratseth@yahoo-inc.com">Jon Bratseth</a>
+ */
+public final class XmlHelper {
+    private static final Logger log = Logger.getLogger(XmlHelper.class.getPackage().toString());
+
+
+    private static final String idReference = "idref";
+    // Access to this needs to be synchronized (as it is in getDocumentBuilder() below)
+    public static final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+
+    static {
+        XmlHelper.factory.setNamespaceAware(true);
+        // if use jdom and jaxen this will fail badly:
+        XmlHelper.factory.setXIncludeAware(true);
+    }
+
+    private XmlHelper() {}
+
+    public static String nullIfEmpty(String attribute) {
+        if (attribute.isEmpty())
+            return null;
+        else
+            return attribute;
+    }
+
+    /**
+     * For searchers inside search chains, the id may be both a reference and an id at once, or just a reference.
+     * In other cases, it is clear which one it is from context, so I think the difference is not worth bothering users
+     * with, unless they are XML purists in which case they will have the option of writing this correctly.
+     * - Jon
+     */
+    public static String getIdString(Element element) {
+        String idString = element.getAttribute("id");
+        if (idString == null || idString.trim().equals(""))
+            idString = element.getAttribute(idReference);
+        if (idString == null || idString.trim().equals(""))
+            idString = element.getAttribute("ident");
+        return idString;
+    }
+
+    public static ComponentId getId(Element element) {
+        return new ComponentId(getIdString(element));
+    }
+
+    public static ComponentSpecification getIdRef(Element element) {
+        return new ComponentSpecification(getIdString(element));
+    }
+
+    public static Document getDocument(Reader reader) {
+        Document doc;
+        try {
+            doc = getDocumentBuilder().parse(new InputSource(reader));
+        } catch (SAXException | IOException e) {
+            throw new IllegalArgumentException(e);
+        }
+        return doc;
+    }
+
+    public static List<String> splitAndDiscardEmpty(String field, String regex) {
+        List<String> ret = new ArrayList<>();
+        for (String t : field.split(regex)) {
+            if (!t.isEmpty()) {
+                ret.add(t);
+            }
+        }
+        return ret;
+    }
+
+    public static List<String> spaceSeparatedSymbols(String field) {
+        return splitAndDiscardEmpty(field, " ");
+    }
+
+    public static Collection<String> spaceSeparatedSymbolsFromAttribute(Element spec, String name) {
+        return spaceSeparatedSymbols(spec.getAttribute(name));
+    }
+
+    public static Collection<String> valuesFromElements(Element parent, String elementName) {
+        List<String> symbols = new ArrayList<>();
+        for (Element symbol : XML.getChildren(parent, elementName)) {
+            symbols.add(XML.getValue(symbol).trim());
+        }
+        return symbols;
+    }
+
+    public static boolean isReference(Element element) {
+        return element.hasAttribute(idReference);
+    }
+
+    /**
+     * Creates a new XML document builder.
+     *
+     * @return A new DocumentBuilder instance, or null if we fail to get one.
+     */
+    public static synchronized DocumentBuilder getDocumentBuilder() {
+        try {
+            DocumentBuilder docBuilder = factory.newDocumentBuilder();
+            log.log(LogLevel.DEBUG, "XML parser now operational!");
+            return docBuilder;
+        } catch (ParserConfigurationException e) {
+            log.log(LogLevel.WARNING, "No XML parser available - " + e);
+            return null;
+        }
+    }
+
+    public static Optional<String> getOptionalAttribute(Element element, String name) {
+        return Optional.ofNullable(element.getAttribute(name)).filter(s -> !s.isEmpty());
+    }
+}
diff --git a/config-model/src/main/java/com/yahoo/config/model/builder/xml/package-info.java b/config-model/src/main/java/com/yahoo/config/model/builder/xml/package-info.java
new file mode 100644
index 00000000000..6ce400dc922
--- /dev/null
+++ b/config-model/src/main/java/com/yahoo/config/model/builder/xml/package-info.java
@@ -0,0 +1,5 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+@ExportPackage
+package com.yahoo.config.model.builder.xml;
+
+import com.yahoo.osgi.annotation.ExportPackage;