org.apache.commons.jexl3.internal.TemplateScript Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.commons.jexl3.internal;
import org.apache.commons.jexl3.JexlContext;
import org.apache.commons.jexl3.JexlInfo;
import org.apache.commons.jexl3.JxltEngine;
import org.apache.commons.jexl3.internal.TemplateEngine.Block;
import org.apache.commons.jexl3.internal.TemplateEngine.BlockType;
import org.apache.commons.jexl3.internal.TemplateEngine.TemplateExpression;
import org.apache.commons.jexl3.parser.ASTJexlScript;
import org.apache.commons.jexl3.JexlException;
import org.apache.commons.jexl3.JexlOptions;
import org.apache.commons.jexl3.parser.ASTArguments;
import org.apache.commons.jexl3.parser.ASTFunctionNode;
import org.apache.commons.jexl3.parser.ASTIdentifier;
import org.apache.commons.jexl3.parser.ASTNumberLiteral;
import org.apache.commons.jexl3.parser.JexlNode;
import java.io.Reader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
/**
* A Template instance.
*/
public final class TemplateScript implements JxltEngine.Template {
/** The prefix marker. */
private final String prefix;
/** The array of source blocks. */
private final Block[] source;
/** The resulting script. */
private final ASTJexlScript script;
/** The TemplateEngine expressions called by the script. */
private final TemplateExpression[] exprs;
/** The engine. */
private final TemplateEngine jxlt;
/**
* Creates a new template from an character input.
* @param engine the template engine
* @param info the source info
* @param directive the prefix for lines of code; can not be "$", "${", "#" or "#{"
since this would preclude being able to differentiate directives and jxlt expressions
* @param reader the input reader
* @param parms the parameter names
* @throws NullPointerException if either the directive prefix or input is null
* @throws IllegalArgumentException if the directive prefix is invalid
*/
public TemplateScript(final TemplateEngine engine,
JexlInfo info,
final String directive,
final Reader reader,
final String... parms) {
if (directive == null) {
throw new NullPointerException("null prefix");
}
final String engineImmediateCharString = Character.toString(engine.getImmediateChar());
final String engineDeferredCharString = Character.toString(engine.getDeferredChar());
if (engineImmediateCharString.equals(directive)
|| engineDeferredCharString.equals(directive)
|| (engineImmediateCharString + "{").equals(directive)
|| (engineDeferredCharString + "{").equals(directive)) {
throw new IllegalArgumentException(directive + ": is not a valid directive pattern");
}
if (reader == null) {
throw new NullPointerException("null input");
}
this.jxlt = engine;
this.prefix = directive;
final List blocks = jxlt.readTemplate(prefix, reader);
final List uexprs = new ArrayList<>();
final StringBuilder strb = new StringBuilder();
int nuexpr = 0;
int codeStart = -1;
int line = 1;
for (int b = 0; b < blocks.size(); ++b) {
final Block block = blocks.get(b);
final int bl = block.getLine();
while(line < bl) {
strb.append("//\n");
line += 1;
}
if (block.getType() == BlockType.VERBATIM) {
strb.append("jexl:print(");
strb.append(nuexpr++);
strb.append(");\n");
line += 1;
} else {
// keep track of first block of code, the frame creator
if (codeStart < 0) {
codeStart = b;
}
final String body = block.getBody();
strb.append(body);
for(int c = 0; c < body.length(); ++c) {
if (body.charAt(c) == '\n') {
line += 1;
}
}
}
}
// create the script
if (info == null) {
info = jxlt.getEngine().createInfo();
}
// allow lambda defining params
final Scope scope = parms == null ? null : new Scope(null, parms);
script = jxlt.getEngine().parse(info.at(1, 1), false, strb.toString(), scope).script();
// seek the map of expression number to scope so we can parse Unified
// expression blocks with the appropriate symbols
final Map minfo = new TreeMap<>();
collectPrintScope(script.script(), minfo);
// jexl:print(...) expression counter
int jpe = 0;
// create the exprs using the intended scopes
for (final Block block : blocks) {
if (block.getType() == BlockType.VERBATIM) {
final JexlNode.Info ji = minfo.get(jpe);
TemplateExpression te;
// no node info means this verbatim is surrounded by comments markers;
// expr at this index is never called
if (ji != null) {
te = jxlt.parseExpression(ji, block.getBody(), scopeOf(ji));
} else {
te = jxlt.new ConstantExpression(block.getBody(), null);
}
uexprs.add(te);
jpe += 1;
}
}
source = blocks.toArray(new Block[blocks.size()]);
exprs = uexprs.toArray(new TemplateExpression[uexprs.size()]);
}
/**
* Private ctor used to expand deferred expressions during prepare.
* @param engine the template engine
* @param thePrefix the directive prefix
* @param theSource the source
* @param theScript the script
* @param theExprs the expressions
*/
TemplateScript(final TemplateEngine engine,
final String thePrefix,
final Block[] theSource,
final ASTJexlScript theScript,
final TemplateExpression[] theExprs) {
jxlt = engine;
prefix = thePrefix;
source = theSource;
script = theScript;
exprs = theExprs;
}
/**
* Gets the scope from an info.
* @param info the node info
* @return the scope
*/
private static Scope scopeOf(final JexlNode.Info info) {
JexlNode walk = info.getNode();
while(walk != null) {
if (walk instanceof ASTJexlScript) {
return ((ASTJexlScript) walk).getScope();
}
walk = walk.jjtGetParent();
}
return null;
}
/**
* Collects the scope surrounding a call to jexl:print(i).
* This allows to later parse the blocks with the known symbols
* in the frame visible to the parser.
* @param node the visited node
* @param minfo the map of printed expression number to node info
*/
private static void collectPrintScope(final JexlNode node, final Map minfo) {
final int nc = node.jjtGetNumChildren();
if (node instanceof ASTFunctionNode && nc == 2) {
// 0 must be the prefix jexl:
final ASTIdentifier nameNode = (ASTIdentifier) node.jjtGetChild(0);
if ("print".equals(nameNode.getName()) && "jexl".equals(nameNode.getNamespace())) {
final ASTArguments argNode = (ASTArguments) node.jjtGetChild(1);
if (argNode.jjtGetNumChildren() == 1) {
// seek the epression number
final JexlNode arg0 = argNode.jjtGetChild(0);
if (arg0 instanceof ASTNumberLiteral) {
final int exprNumber = ((ASTNumberLiteral) arg0).getLiteral().intValue();
minfo.put(exprNumber, new JexlNode.Info(nameNode));
return;
}
}
}
}
for (int c = 0; c < nc; ++c) {
collectPrintScope(node.jjtGetChild(c), minfo);
}
}
/**
* @return script
*/
ASTJexlScript getScript() {
return script;
}
/**
* @return exprs
*/
TemplateExpression[] getExpressions() {
return exprs;
}
@Override
public String toString() {
final StringBuilder strb = new StringBuilder();
for (final Block block : source) {
block.toString(strb, prefix);
}
return strb.toString();
}
@Override
public String asString() {
final StringBuilder strb = new StringBuilder();
int e = 0;
for (final Block block : source) {
if (block.getType() == BlockType.DIRECTIVE) {
strb.append(prefix);
strb.append(block.getBody());
} else {
exprs[e++].asString(strb);
}
}
return strb.toString();
}
@Override
public TemplateScript prepare(final JexlContext context) {
final Engine jexl = jxlt.getEngine();
final JexlOptions options = jexl.options(script, context);
final Frame frame = script.createFrame((Object[]) null);
final TemplateInterpreter.Arguments targs = new TemplateInterpreter
.Arguments(jxlt.getEngine())
.context(context)
.options(options)
.frame(frame);
final Interpreter interpreter = new TemplateInterpreter(targs);
final TemplateExpression[] immediates = new TemplateExpression[exprs.length];
for (int e = 0; e < exprs.length; ++e) {
try {
immediates[e] = exprs[e].prepare(interpreter);
} catch (final JexlException xjexl) {
final JexlException xuel = TemplateEngine.createException(xjexl.getInfo(), "prepare", exprs[e], xjexl);
if (jexl.isSilent()) {
jexl.logger.warn(xuel.getMessage(), xuel.getCause());
return null;
}
throw xuel;
}
}
return new TemplateScript(jxlt, prefix, source, script, immediates);
}
@Override
public void evaluate(final JexlContext context, final Writer writer) {
evaluate(context, writer, (Object[]) null);
}
@Override
public void evaluate(final JexlContext context, final Writer writer, final Object... args) {
final Engine jexl = jxlt.getEngine();
final JexlOptions options = jexl.options(script, context);
final Frame frame = script.createFrame(args);
final TemplateInterpreter.Arguments targs = new TemplateInterpreter
.Arguments(jexl)
.context(context)
.options(options)
.frame(frame)
.expressions(exprs)
.writer(writer);
final Interpreter interpreter = new TemplateInterpreter(targs);
interpreter.interpret(script);
}
@Override
public Set> getVariables() {
final Engine.VarCollector collector = jxlt.getEngine().varCollector();
for (final TemplateExpression expr : exprs) {
expr.getVariables(collector);
}
return collector.collected();
}
@Override
public String[] getParameters() {
return script.getParameters();
}
@Override
public Map getPragmas() {
return script.getPragmas();
}
}