com.google.template.soy.shared.internal.BackendModuleUtils.java Source code

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Here is the source code for com.google.template.soy.shared.internal.BackendModuleUtils.java

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/*
 * Copyright 2009 Google Inc.
 *
 * 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 com.google.template.soy.shared.internal;

import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Sets;
import com.google.template.soy.shared.restricted.SoyFunction;
import com.google.template.soy.shared.restricted.SoyPrintDirective;

import java.util.Map;
import java.util.Set;

/**
 * Utilities for backend modules (TofuModule, JsSrcModule, JavaSrcModule).
 *
 * <p> Important: Do not use outside of Soy code (treat as superpackage-private).
 *
 * @author Kai Huang
 */
public class BackendModuleUtils {

    private BackendModuleUtils() {
    }

    /**
     * Given a backend-specific Soy function type and the set of all Soy function implementations,
     * finds the Soy functions that are implemented for the specific backend and returns them in the
     * form of a map from function name to function.
     *
     * @param backendSpecificSoyFunctionType The backend-specific Soy function type to filter for.
     * @param soyFunctionsSet The set of all Soy functions.
     * @return A map of the relevant backend-specific Soy functions (name to function).
     */
    public static <T extends SoyFunction> Map<String, T> buildBackendSpecificSoyFunctionsMap(
            Class<T> backendSpecificSoyFunctionType, Set<SoyFunction> soyFunctionsSet) {

        ImmutableMap.Builder<String, T> mapBuilder = ImmutableMap.builder();

        Set<String> seenFnNames = Sets.newHashSetWithExpectedSize(soyFunctionsSet.size());

        for (SoyFunction fn : soyFunctionsSet) {
            if (backendSpecificSoyFunctionType.isAssignableFrom(fn.getClass())) {
                String fnName = fn.getName();

                if (seenFnNames.contains(fnName) || ImpureFunction.forFunctionName(fnName) != null) {
                    throw new IllegalStateException(
                            "Found two implementations of " + backendSpecificSoyFunctionType.getSimpleName()
                                    + " with the same function name '" + fnName + "'.");
                }
                seenFnNames.add(fnName);

                mapBuilder.put(fnName, backendSpecificSoyFunctionType.cast(fn));
            }
        }

        return mapBuilder.build();
    }

    /**
     * Given a backend-specific Soy directive type and the set of all Soy directive implementations,
     * finds the Soy directives that are implemented for the specific backend and returns them in the
     * form of a map from directive name to directive.
     *
     * @param backendSpecificSoyDirectiveType The backend-specific Soy directive type to filter for.
     * @param soyDirectivesSet The set of all Soy directives.
     * @return A map of the relevant backend-specific Soy directives (name to directive).
     */
    public static <T extends SoyPrintDirective> Map<String, T> buildBackendSpecificSoyDirectivesMap(
            Class<T> backendSpecificSoyDirectiveType, Set<SoyPrintDirective> soyDirectivesSet) {

        ImmutableMap.Builder<String, T> mapBuilder = ImmutableMap.builder();

        Set<String> seenDirectiveNames = Sets.newHashSetWithExpectedSize(soyDirectivesSet.size());

        for (SoyPrintDirective directive : soyDirectivesSet) {
            if (backendSpecificSoyDirectiveType.isAssignableFrom(directive.getClass())) {
                String directiveName = directive.getName();

                if (seenDirectiveNames.contains(directiveName)) {
                    throw new IllegalStateException(
                            "Found two implementations of " + backendSpecificSoyDirectiveType.getSimpleName()
                                    + " with the same directive name '" + directiveName + "'.");
                }
                seenDirectiveNames.add(directiveName);

                mapBuilder.put(directiveName, backendSpecificSoyDirectiveType.cast(directive));
            }
        }

        return mapBuilder.build();
    }

}