Java tutorial
/* Copyright 2014 Immutables Authors and Contributors 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 org.immutables.generator.processor; import com.google.common.base.Optional; import com.google.common.collect.ImmutableList; import com.google.common.collect.Lists; import java.util.Collection; import java.util.List; import javax.lang.model.element.TypeElement; import org.immutables.generator.Intrinsics; import org.immutables.generator.Templates; import org.immutables.generator.processor.ImmutableTrees.ApplyExpression; import org.immutables.generator.processor.ImmutableTrees.AssignGenerator; import org.immutables.generator.processor.ImmutableTrees.Block; import org.immutables.generator.processor.ImmutableTrees.BoundAccessExpression; import org.immutables.generator.processor.ImmutableTrees.Comment; import org.immutables.generator.processor.ImmutableTrees.ConditionalBlock; import org.immutables.generator.processor.ImmutableTrees.ForStatement; import org.immutables.generator.processor.ImmutableTrees.Identifier; import org.immutables.generator.processor.ImmutableTrees.IfStatement; import org.immutables.generator.processor.ImmutableTrees.InvokableDeclaration; import org.immutables.generator.processor.ImmutableTrees.InvokeStatement; import org.immutables.generator.processor.ImmutableTrees.InvokeString; import org.immutables.generator.processor.ImmutableTrees.IterationGenerator; import org.immutables.generator.processor.ImmutableTrees.LetStatement; import org.immutables.generator.processor.ImmutableTrees.ResolvedType; import org.immutables.generator.processor.ImmutableTrees.StringLiteral; import org.immutables.generator.processor.ImmutableTrees.Template; import org.immutables.generator.processor.ImmutableTrees.TextLine; import org.immutables.generator.processor.ImmutableTrees.TransformGenerator; import org.immutables.generator.processor.ImmutableTrees.Unit; import org.immutables.generator.processor.ImmutableTrees.ValueDeclaration; import org.immutables.generator.processor.Trees.Expression; import static org.immutables.generator.StringLiterals.toLiteral; /** * This part is written with simples possible writer in mind. It was decided not to use dependencies * like. Its is possible that in future it will be replaced with self bootstraping, i.e. template * generator will be generated by the same framework which generates templates. */ public final class TemplateWriter extends TreesTransformer<TemplateWriter.Context> { private final TypeElement sourceElement; private final String simpleName; private final SwissArmyKnife knife; public TemplateWriter(SwissArmyKnife knife, TypeElement sourceElement, String simpleName) { this.knife = knife; this.sourceElement = sourceElement; this.simpleName = simpleName; } public CharSequence toCharSequence(Unit unit) { Context context = new Context(); transform(context, unit); return context.builder; } @Override public Unit transform(Context context, Unit value) { context.out("package ", knife.elements.getPackageOf(sourceElement).getQualifiedName(), ";").ln().ln() .out("import static ", Intrinsics.class, ".*;").ln().ln(); context.out("@", SuppressWarnings.class, "(", toLiteral("all"), ")").ln() .out("public class ", simpleName, " extends ", sourceElement.getQualifiedName()).out(" ") .openBrace(); int braces = context.getAndSetPendingBraces(0); Unit unit = super.transform(context, value); writeTemplateDispatch(context); context.getAndSetPendingBraces(braces); context.ln().closeBraces().ln(); return unit; } private void writeTemplateDispatch(Context context) { int initialBraces = context.getAndSetPendingBraces(0); context.out("private class FragmentDispatch extends ", Templates.Fragment.class, "").openBrace().ln() .out("private final int index;").ln().out("FragmentDispatch(int arity, int index)").openBrace().ln() .out("super(arity);").ln().out("this.index = index;").ln().closeBrace().ln() .out("@Override public void run(", Templates.Invokation.class, " invokation)").openBrace().indent() .ln().out("switch (index)").openBrace().ln(); for (int i = 0; i < context.templateIndex.size(); i++) { String templateName = context.templateIndex.get(i); context.out("case ", i, ": _t", i, "__", templateName, "(invokation); break;").ln(); } context.out("default: break;"); context.outdent().ln().closeBraces().ln().getAndSetPendingBraces(initialBraces); } @Override public Template transform(final Context context, final Template template) { String name = template.declaration().name().value(); context.ln().out(template.isPublic() ? "public " : "").out(Templates.Invokable.class).out(" ").out(name) .out("() { return ").out(name).out("; }").ln(); context.out("private "); new DispatchedTemplateLike() { { declaration = template.declaration(); variable = true; } @Override void body() { transformTemplateDeclaration(context, template, template.declaration()); transformTemplateListParts(context, template, template.parts()); } }.generate(context); context.out(";").ln(); return template; } abstract class DispatchedTemplateLike { boolean variable; Trees.InvokableDeclaration declaration; final void generate(Context context) { if (variable) { context.out("final ").out(Templates.Invokable.class).out(" ").out(declaration.name().value()) .out(" = "); } String templateName = declaration.name().value(); int templateIndex = context.indexTemplate(templateName); context.out("new FragmentDispatch(", declaration.parameters().size(), ", ", templateIndex, ");").ln(); context.out("void _t", templateIndex, "__", templateName, "(").out(Templates.Invokation.class) .out(" __) ").openBrace().indent().ln(); int braces = context.getAndSetPendingBraces(0); context.delimit(); body(); context.delimit(); context.getAndSetPendingBraces(braces); context.outdent().ln().closeBraces(); } abstract void body(); } abstract class TemplateLike { boolean variable; Trees.InvokableDeclaration declaration; final void generate(Context context) { if (variable) { context.out("final ").out(Templates.Invokable.class).out(" ").out(declaration.name().value()) .out(" = "); } context.out("new ").out(Templates.Fragment.class).out("(", declaration.parameters().size(), ") ") .openBrace().ln().out("@Override public void run(").out(Templates.Invokation.class).out(" __) ") .openBrace().indent().ln(); int braces = context.getAndSetPendingBraces(0); context.delimit(); body(); context.delimit(); context.getAndSetPendingBraces(braces); context.outdent().ln().closeBraces(); } abstract void body(); } @Override public LetStatement transform(final Context context, final LetStatement statement) { new TemplateLike() { { declaration = statement.declaration(); variable = true; } @Override void body() { context.out("final ").out(Templates.Invokable.class).out(" ") .out(statement.declaration().name().value()).out(" = this;").ln(); transformLetStatementDeclaration(context, statement, statement.declaration()); transformLetStatementListParts(context, statement, statement.parts()); } }.generate(context); context.out(";").delimit(); return statement; } @Override public ForStatement transform(Context context, ForStatement statement) { context.openBrace(); if (statement.useForAccess()) { context.infor().out("final ").out(Templates.Iteration.class).out(" ") .out(context.accessMapper(TypeResolver.ITERATION_ACCESS_VARIABLE)).out(" = new ") .out(Templates.Iteration.class).out("();").ln(); } transformForStatementListDeclaration(context, statement, statement.declaration()); int braces = context.getAndSetPendingBraces(0); context.indent(); if (statement.useDelimit()) { context.delimit(); } transformForStatementListParts(context, statement, statement.parts()); if (statement.useDelimit()) { context.delimit(); } if (statement.useForAccess()) { context.out(context.accessMapper(TypeResolver.ITERATION_ACCESS_VARIABLE)).out(".index++;").ln(); context.out(context.accessMapper(TypeResolver.ITERATION_ACCESS_VARIABLE)).out(".first = false;"); context.outfor(); } context.getAndSetPendingBraces(braces); context.outdent().ln().closeBraces().ln(); if (statement.useDelimit()) { context.delimit(); } return statement; } @Override public InvokeString transform(Context context, InvokeString value) { context.out("$(__, ", value.literal(), ");").ln(); return value; } @Override public InvokeStatement transform(final Context context, final InvokeStatement statement) { context.out("$(__, "); transformInvokeStatementAccess(context, statement, statement.access()); transformInvokeStatementListParams(context, statement, statement.params()); if (!statement.parts().isEmpty()) { context.out(", "); new TemplateLike() { { declaration = InvokableDeclaration.builder().name(Identifier.of("")).build(); } @Override void body() { transformInvokeStatementListParts(context, statement, statement.parts()); } }.generate(context); } context.out(");").ln(); return statement; } @Override protected Iterable<Expression> transformInvokeStatementListParams(Context context, InvokeStatement value, List<Expression> collection) { for (Trees.Expression element : collection) { context.out(", "); transformInvokeStatementParams(context, value, element); } return collection; } @Override public AssignGenerator transform(Context context, AssignGenerator generator) { transformAssignGeneratorDeclaration(context, generator, generator.declaration()); // context.out(" = (") // .out(requiredResolvedTypeOfDeclaration(generator.declaration())) // .out(") $("); context.out(" = $cast("); transformAssignGeneratorFrom(context, generator, generator.from()); context.out(");").ln(); return generator; } @Override public TransformGenerator transform(Context context, TransformGenerator generator) { context.out(Collection.class).out("<").out(generator.declaration().containedType().get()).out("> ") .out(generator.declaration().name().value()).out(" = ").out(Intrinsics.class).out(".$collect();") .ln(); int braces = context.getAndSetPendingBraces(0); context.out("for ("); transformTransformGeneratorVarDeclaration(context, generator, generator.varDeclaration()); context.out(" : $in("); transformTransformGeneratorFrom(context, generator, generator.from()); context.out(")) ").openBrace().indent().ln(); if (generator.condition().isPresent()) { context.out("if ($if("); transformTransformGeneratorOptionalCondition(context, generator, generator.condition()); context.out(")) ").openBrace().ln(); } context.out(generator.declaration().name().value()).out(".add("); transformTransformGeneratorTransform(context, generator, generator.transform()); context.out(");"); context.outdent().ln().closeBraces(); context.getAndSetPendingBraces(braces); return generator; } @Override public IterationGenerator transform(Context context, IterationGenerator generator) { context.out("for ("); transformIterationGeneratorDeclaration(context, generator, generator.declaration()); context.out(" : $in("); transformIterationGeneratorFrom(context, generator, generator.from()); context.out(")) ").openBrace().ln(); if (generator.condition().isPresent()) { context.out("if ($if("); transformIterationGeneratorOptionalCondition(context, generator, generator.condition()); context.out(")) ").openBrace().ln(); } return generator; } @Override public ValueDeclaration transform(Context context, ValueDeclaration value) { context.out("final ").out(requiredResolvedTypeOfDeclaration(value)).out(" ").out(value.name().value()); return value; } private Object requiredResolvedTypeOfDeclaration(Trees.ValueDeclaration value) { return ((ResolvedType) value.type().get()).type(); } @Override public TextLine transform(Context context, TextLine line) { if (line.fragment().value().isEmpty()) { if (line.newline()) { context.out("__.ln();").ln(); } } else { context.out("__.out(").out(line.fragment()).out(line.newline() ? ").ln();" : ");").ln(); } return line; } @Override public StringLiteral transform(Context context, StringLiteral value) { context.out(value); return value; } @Override public BoundAccessExpression transform(Context context, BoundAccessExpression value) { ImmutableList<Accessors.BoundAccess> accessList = TypeResolver.asBoundAccess(value.accessor()); StringBuilder expressionBuilder = new StringBuilder(); for (int i = 0; i < accessList.size(); i++) { boolean first = i == 0; boolean last = i != accessList.size() - 1; Accessors.BoundAccess access = accessList.get(i); if (!first) { expressionBuilder.append("."); } String name = access.name; if (first) { name = context.accessMapper(name); } expressionBuilder.append(name).append(access.callable ? "()" : ""); if (access.boxed && last) { expressionBuilder.insert(0, "$("); expressionBuilder.append(")"); } } context.out(expressionBuilder); return value; } @Override public ApplyExpression transform(Context context, ApplyExpression value) { context.out("$("); ApplyExpression expression = super.transform(context, value); context.out(")"); return expression; } @Override protected Iterable<Expression> transformApplyExpressionListParams(Context context, ApplyExpression value, List<Expression> collection) { boolean first = true; for (Trees.Expression element : collection) { if (!first) { context.out(", "); } first = false; transformApplyExpressionParams(context, value, element); } return collection; } private void writeConditionPart(Context context, ConditionalBlock block) { context.out("if ($if("); transformConditionalBlockCondition(context, block, block.condition()); context.out(")) {").indent().ln(); context.delimit(); transformConditionalBlockListParts(context, block, block.parts()); } @Override public IfStatement transform(Context context, IfStatement statement) { context.delimit().ln(); writeConditionPart(context, (ConditionalBlock) statement.then()); for (Trees.ConditionalBlock block : statement.otherwiseIf()) { context.outdent().out("} else "); writeConditionPart(context, (ConditionalBlock) block); } if (statement.otherwise().isPresent()) { context.outdent().ln().out("} else {").indent().ln().delimit(); transform(context, (Block) statement.otherwise().get()); } context.outdent().ln().out("}").ln().delimit(); return statement; } @Override public Comment transform(Context context, Comment value) { context.delimit(); return value; } @Override public InvokableDeclaration transform(Context context, InvokableDeclaration value) { int count = 0; for (Trees.Parameter parameter : value.parameters()) { int paramIndex = count++; String typeName = parameter.type().toString(); context.out("final ", typeName, " ", parameter.name().value()).out(" = "); if (typeName.equals(String.class.getName())) { context.out("__.param(", paramIndex, ").toString();").ln(); } else if (typeName.equals(Boolean.class.getName())) { context.out("$if(__.param(", paramIndex, "));").ln(); } else if (typeName.equals(Object.class.getName())) { context.out("__.param(", paramIndex, ");").ln(); } else { context.out("$cast(__.param(", paramIndex, "));").ln(); } } return super.transform(context, value); } static class Context { final List<String> templateIndex = Lists.newArrayListWithExpectedSize(100); final StringBuilder builder = new StringBuilder(); private int indentLevel; private int bracesToClose; private int forLevels; Context infor() { forLevels++; return this; } Context delimit() { // Avoid delimits on a top level when there's not surrounding template if (indentLevel > 0) { out("__.dl();"); } return this; } Context outfor() { forLevels--; return this; } Context indent() { indentLevel++; return this; } Context outdent() { indentLevel--; return this; } Context out(Object... objects) { for (Object object : objects) { out(object); } return this; } int indexTemplate(String template) { int index = templateIndex.size(); templateIndex.add(template); return index; } public String accessMapper(String identifer) { if (TypeResolver.ITERATION_ACCESS_VARIABLE.equals(identifer)) { return "_it" + forLevels; } return identifer; } int getAndSetPendingBraces(int bracesToClose) { int value = this.bracesToClose; this.bracesToClose = bracesToClose; return value; } Context closeBraces() { for (int i = 0; i < bracesToClose; i++) { builder.append('}'); } bracesToClose = 0; return this; } Context openBrace() { builder.append('{'); bracesToClose++; return this; } Context closeBrace() { builder.append('}'); bracesToClose--; return this; } Context out(Object object) { if (object instanceof Optional<?>) { object = ((Optional<?>) object).orNull(); } if (object instanceof Class<?>) { object = ((Class<?>) object).getCanonicalName(); } if (object instanceof CharSequence) { builder.append((CharSequence) object); return this; } builder.append(String.valueOf(object)); return this; } Context ln() { builder.append('\n'); for (int i = 0; i < indentLevel; i++) { builder.append(" "); } return this; } } }